Display device

Abstract

In an organic EL display device having a proximity sensor, a decrease in display quality caused by irradiation with IR light is suppressed. A light-shielding portion is provided in the organic EL display device having a proximity sensor, and the light-shielding portion prevents IR light from irradiating a channel layer of a first initialization transistor, which is provided in a pixel circuit to initialize a voltage applied to a control terminal of a driving transistor. The first initialization transistor preferably has a double-gate structure. In addition, the first initialization transistor may have an LDD structure (including a single-sided LDD structure).

Description

Technical Field

[0001] The following disclosure relates to a display device including a proximity sensor. Background Art

[0002] In recent years, organic EL display devices including pixel circuits having organic EL elements have been put into practical use. An organic EL element, also known as an OLED (Organic Light-Emitting Diode), is a self-emitting display element that emits light with a brightness corresponding to the current flowing through it. Thus, since the organic EL element is a self-emitting display element, an organic EL display device can be easily thinned, reduced in power consumption, and increased in brightness compared to a liquid crystal display device that requires a backlight and color filters.

[0003] Regarding the above-described organic EL display device, in recent years, the mounting of a proximity sensor for detecting the presence or absence of an object at a proximity position has been promoted. A proximity sensor mounted on an organic EL display device typically includes an emitting portion that emits IR light (infrared light) from the back surface of the display portion, and a light receiving portion that receives the reflected light of the IR light. The presence or absence of an object at a proximity position is determined based on the magnitude of the current generated according to the amount of the reflected light received by the light receiving portion.

[0004] An invention regarding the above-described display device including a proximity sensor has been disclosed in Japanese Patent Application Laid-Open No. 2009-223896. In the display device disclosed in Japanese Patent Application Laid-Open No. 2009-223896, a structure in which an infrared sensor as a proximity sensor is built in a display panel is adopted. In addition, as content related to the configuration of the following embodiment, in Japanese Patent Application Laid-Open No. 2013-38441, it is described that a light shielding layer is provided so that light from a light source is not incident on the channel region of a thin film transistor, although this description is regarding a radiation detection device.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-223896

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2013-38441 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] However, regarding an organic EL display device equipped with a proximity sensor, a degradation in display quality becomes a problem. Regarding this problem, attention is focused on the case of using a pixel circuit (a pixel circuit including one organic EL element 61, seven transistors T1 to T7 (a first initialization transistor T1, a threshold voltage compensation transistor T2, a write control transistor T3, a driving transistor T4, a power supply control transistor T5, a light emission control transistor T6, a second initialization transistor T7), and one holding capacitor Ca) 60 as shown in Figure 17 and the following description will be made.

[0011] In addition, in this specification, for convenience, the state in which a data signal (display data) is being written into the pixel circuit 60 (the state in which the threshold voltage compensation transistor T2 and the write control transistor T3 are conductive) is referred to as "scan on", and the state in which a data signal is not being written into the pixel circuit 60 (the state in which the threshold voltage compensation transistor T2 and the write control transistor T3 are non-conductive) is referred to as "scan off". Also, for convenience, the state in which a driving current is supplied to the organic EL element 61 (the state in which the power supply control transistor T5 and the light emission control transistor T6 are conductive) is referred to as "emission on", and the state in which a driving current is not supplied to the organic EL element 61 (the state in which the power supply control transistor T5 and the light emission control transistor T6 are non-conductive) is referred to as "emission off". In addition, the area of the entire display section irradiated with IR light emitted from the emission section of the proximity sensor is referred to as the "IR light irradiation area (infrared light irradiation area)".

[0012] Hereinafter, attention is focused on the pixel circuit 60 within the IR light irradiation area. When IR light is being irradiated, compared with when IR light is not being irradiated, the on-currents and off-currents of all the transistors T1 to T7 increase. Regarding this, depending on the irradiation timing of the IR light, the influence on display and the like is different.

[0013] First, the influence on display and the like when IR light is irradiated in the scan-off state will be described. In this case, since the off-currents of the first initialization transistor T1 and the threshold voltage compensation transistor T2 increase, the potential of the control node NG changes (the voltage between both ends of the holding capacitor Ca changes). Specifically, the potential of the control node NG drops. As a result, when it becomes the emission-on state, the driving current passing through the power supply control transistor T5, the driving transistor T4, and the light emission control transistor T6 will relatively increase, and the characteristics of the driving transistor T4 change. Figure 18 is a diagram for explaining an example of the change in the current-voltage characteristics when IR light is irradiated on a thin-film transistor. In Figure 18In [the figure], the characteristics are shown when the drain-source voltage Vds is set to -10V and a certain test LTPS-TFT (a thin-film transistor using low-temperature polysilicon in the channel layer) is used in the saturation region. The solid line 901 shows the characteristics of the case where the thin-film transistor is not irradiated with IR light, and the thick dashed line 902 shows the characteristics of the case where the thin-film transistor is irradiated with IR light. From the dashed-line part marked with the reference numeral 90, it can be understood that: by the irradiation of IR light, the cut-off current increases significantly.

[0014] In addition, although the on-current or cut-off current of all transistors increases, the increase in the cut-off current of the first initialization transistor T1 and the threshold voltage compensation transistor T2 has a great impact on the display brightness. In this regard, in the case of a thin-film transistor having a top-gate structure, since IR light is emitted from the back surface of the display unit, the IR light irradiates the channel region of the thin-film transistor. As a result, holes and electrons are excited, and the cut-off current increases significantly.

[0015] When the drive current increases as described above, the emission brightness of the organic EL element 61 becomes higher than the original brightness, so the display of the corresponding part is visually recognized as a bright spot (the pixel of the corresponding part will be high-brightness). Figure 19 is a schematic diagram for explaining the high-brightness of the pixel. As Figure 19 shown, a cover glass 91 is provided on the front surface of the organic EL module 92, and a protective sheet 93 is provided on the back surface of the organic EL module 92. A proximity sensor 94 is provided in contact with the protective sheet 93. The proximity sensor 94 includes an emitting portion 941 that emits infrared light and a light-receiving portion 942 that receives the reflected light of the infrared light. Since the organic EL element in the organic EL module 92 emits light, the lighting light is emitted from the display surface. In the IR light irradiation region, as described above, along with the increase in the cut-off current of the first initialization transistor T1 and the threshold voltage compensation transistor T2, the drive current increases, so that the lighting light becomes high-brightness.

[0016] Furthermore, after the potential of the control node NG changes due to the irradiation of IR light, even if the IR light is turned off, the potential of the control node NG remains in the changed state. Therefore, even after the IR light is turned off, a brightness display that is significantly different from the desired brightness display is performed. Refer to Figure 20 and Figure 21 to illustrate this. Figure 20 The thick dashed line 903 in Figure 21 and the thick dashed line 905 in Figure 20 show the optical response of the display brightness in the case where no IR light is irradiated, Figure 21 and the solid line 904 in Figure 20In the case of, the display is "white gray level value = 255 (maximum gray level)", and in Figure 21 the case of, the display is "white gray level value = 48". In addition, the irradiation of IR light is performed at a timing when the pulse width of the IR light is set to 1.9 ms and the duty ratio is set to 2.09% with scanning off and emission on. According to Figure 20 the thick dashed line 903, it can be understood that when the display of "white gray level value = 255" is performed, if there is no irradiation of IR light, the display brightness is maintained at about 1,000 cd / m 2 . As Figure 20 the solid line 904 shows, when the display of "white gray level value = 255" is performed, the display brightness rises to about 2,700 cd / m 2 at the irradiation timing of the IR light, and after the IR light is turned off, the display brightness slightly decreases but is maintained at about 2,500 cd / m 2 until the start time of the next frame. In addition, according to Figure 21 the thick dashed line 905, it can be understood that when the display of "white gray level value = 48" is performed, if there is no irradiation of IR light, the display brightness is maintained at about 30 cd / m 2 . As Figure 21 the solid line 906 shows, when the display of "white gray level value = 48" is performed, the display brightness rises to about 1,400 cd / m 2 at the irradiation timing of the IR light, and this display brightness is maintained until the start time of the next frame. As described above, after the IR light is turned off, a brightness display that is significantly different from the desired brightness display is also performed.

[0017] In addition, when the drive current increases as described above, afterimages are generated at corresponding parts due to high current stress after the IR light is turned off. These afterimages may be visually recognized as white dots or black dots when the IR light is not irradiated depending on the surrounding brightness or the intensity of the IR light. That is, the afterimages become a cause of deterioration in display quality.

[0018] Next, the influence on display and the like when the IR light is irradiated when scanning is on will be described. In this case, during the period when the data signal is being written, the conduction currents of the write control transistor T3, the drive transistor T4, and the threshold voltage compensation transistor T2 relatively increase. Therefore, the data signal cannot be correctly written, and the desired gray level display cannot be performed until the next data signal is written (until the next frame period). For example, when a solid image is to be displayed, the display of the corresponding part becomes a state different from the display around it. When using Figure 17In the case of the pixel circuit 60 shown (when the driving transistor T4 is a P-channel transistor), the brightness of the corresponding part becomes lower than the brightness of the surroundings, and is instantaneously visually recognized by the viewer as a black dot stain (dirt). In this way, the display quality deteriorates.

[0019] Figure 22 is a timing chart for explaining the irradiation timing of conventional IR light. However, Figure 22 the waveforms shown are an example, and it is assumed that the areas of rows 1 to 6 in the display unit are IR light irradiation areas. The period during which the scan signal SCAN is maintained at a high level is the scan-off period, and the period during which the scan signal SCAN is maintained at a low level is the scan-on period. The period during which the light emission control signal EM is maintained at a high level is the emission-off period, and the period during which the light emission control signal EM is maintained at a low level is the emission-on period. In Figure 22 the example shown, IR light is irradiated during the periods indicated by the arrows labeled P91, P92, and P93. In this way, the irradiation of conventional IR light is not synchronized with the driving operation for image display, but is performed at an arbitrary timing. When IR light is irradiated at an arbitrary timing like this, for example, the pixel circuit 60 of the first row is irradiated with IR light at any of the timings in the following (1) to (7).

[0020] (1) During the scan-on and emission-off periods

[0021] (2) During the scan-off and emission-off periods

[0022] (3) During the scan-off and emission-on periods

[0023] (4) The period spanning from the above (1) to the above (2)

[0024] (5) The period spanning from the above (2) to the above (3)

[0025] (6) The period spanning from the above (3) to the above (2)

[0026] (7) The period spanning from the above (2) to the above (1)

[0027] The optical responses of the display brightness are different from each other in the cases of the above (1) to (7). Therefore, sometimes the pixels in the IR light irradiation area become high-brightness, and sometimes the brightness of the pixels in the IR light irradiation area is lower than the brightness of the surrounding pixels. In this way, the display quality deteriorates. For example, short-term afterimages are generated in the high-brightness pixels. And, during the period when IR light is not irradiated, in the IR light irradiation area, this afterimage (white afterimage or black afterimage) is visually recognized as a speckle. In addition, long-term afterimages are generated due to the accumulation of IR light irradiation, causing irreparable display defects.

[0028] Accordingly, an object of the following disclosure is to suppress a decrease in display quality caused by irradiation with IR light in a display device including a proximity sensor.

[0029] Solutions for Solving the Problems

[0030] A display device according to some embodiments of the present disclosure includes a pixel circuit including a display element driven by current, and includes:

[0031] A display unit including: the pixel circuits arranged in multiple rows and multiple columns; a plurality of data signal lines for supplying data signals to the pixel circuits in corresponding columns; a plurality of scan signal lines for controlling writing of the data signals to the pixel circuits in corresponding rows; a plurality of light emission control lines for controlling whether to supply current to the display elements included in the pixel circuits in corresponding rows; a first power supply line for supplying a high-level power supply voltage; a second power supply line for supplying a low-level power supply voltage; and an initialization power supply line for supplying an initialization voltage; and

[0032] A proximity sensor including an emission unit that emits infrared light from the back surface of the display unit and a light receiving unit that receives reflected light of the infrared light.

[0033] Each pixel circuit includes:

[0034] A control node;

[0035] The display element having a first terminal and a second terminal connected to the second power supply line;

[0036] A driving transistor having a control terminal connected to the control node, a first conduction terminal, and a second conduction terminal, and arranged in series with the display element;

[0037] A light emission control transistor having a control terminal connected to one of the plurality of light emission control lines, a first conduction terminal, and a second conduction terminal, and arranged in series with the display element;

[0038] A holding capacitor having one end connected to the first power supply line and the other end connected to the control node;

[0039] A writing control transistor having a control terminal connected to one of the plurality of scan signal lines, a first conduction terminal connected to one of the plurality of data signal lines, and a second conduction terminal connected to the first conduction terminal of the driving transistor;

[0040] A threshold voltage compensation transistor having a control terminal connected to one of the plurality of scan signal lines, a first conduction terminal connected to the second conduction terminal of the driving transistor, and a second conduction terminal connected to the control node; and

[0041] A first initialization transistor having a control terminal connected to one of the plurality of scan signal lines, a first conduction terminal connected to the control node, and a second conduction terminal connected to the initialization power supply line,

[0042] A first light-shielding portion is provided to prevent the infrared light from irradiating the channel layer of the first initialization transistor.

[0043] Advantages of the Invention

[0044] According to some embodiments of the present disclosure, in a display device, a first light-shielding portion is provided to prevent the infrared light from irradiating the channel layer of the first initialization transistor in the pixel circuit. Therefore, even if the infrared light is emitted from the proximity sensor for sensing, the infrared light will not irradiate the channel layer of the first initialization transistor, and thus the cut-off current of the first initialization transistor will not increase. Therefore, it is possible to suppress the change in the voltage of the control terminal of the driving transistor due to the irradiation of the infrared light. As a result, it is possible to suppress the degradation of the display quality. As described above, in the display device, the degradation of the display quality caused by the irradiation of the infrared light is suppressed as compared with the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a circuit diagram showing the configuration of the pixel circuit of the n-th row and the m-th column in the first embodiment.

[0046] Figure 2 It is a block diagram showing the overall configuration of the organic EL display device according to the above first embodiment.

[0047] Figure 3 It is a diagram for explaining the position where the proximity sensor is provided in the above first embodiment.

[0048] Figure 4 It is a diagram for explaining the IR light irradiation area in the above first embodiment.

[0049] Figure 5 It is a block diagram showing the functional configuration of the proximity sensor in the above first embodiment.

[0050] Figure 6 It is a layout diagram of the pixel circuit in the above first embodiment.

[0051] Figure 7It is a diagram for explaining the arrangement position of the light-shielding portion of the first initialization transistor in the above-described first embodiment.

[0052] Figure 8 It is Figure 7 a cross-sectional view taken along line A-B.

[0053] Figure 9 It is a schematic cross-sectional view for explaining the LDD structure in the above-described first embodiment.

[0054] Figure 10 It is a diagram for explaining the arrangement of the light-shielding portion in the case where the LDD structure is adopted in the above-described first embodiment.

[0055] Figure 11 It is a diagram for explaining the arrangement of the light-shielding portion in the case where the single-sided LDD structure is adopted in the above-described first embodiment.

[0056] Figure 12 It is a timing chart for explaining the operation of the pixel circuit in the above-described first embodiment.

[0057] Figure 13 It is a timing chart for explaining the irradiation timing of the IR light in the above-described first embodiment.

[0058] Figure 14 It is a circuit diagram showing the configuration of the pixel circuit at the n-th row and m-th column in the second embodiment.

[0059] Figure 15 It is a diagram for explaining the arrangement position (first example) of the light-shielding portion of the threshold voltage compensation transistor in the above-described second embodiment.

[0060] Figure 16 It is a diagram for explaining the arrangement position (second example) of the light-shielding portion of the threshold voltage compensation transistor in the above-described second embodiment.

[0061] Figure 17 It is a circuit diagram showing a configuration example of the pixel circuit at the n-th row and m-th column in the prior art.

[0062] Figure 18 It is a diagram for explaining an example of the change in the current-voltage characteristics when the thin film transistor is irradiated with IR light.

[0063] Figure 19 It is a schematic diagram for explaining the high-brightness of the pixel.

[0064] Figure 20 It is a diagram for explaining the influence of the irradiation of IR light on the display brightness.

[0065] Figure 21This is a diagram for explaining the influence of IR light irradiation on display brightness.

[0066] Figure 22 This is a timing diagram for explaining the irradiation timing of conventional IR light. Detailed implementation mode

[0067] Hereinafter, the implementation mode will be described with reference to the accompanying drawings. In addition, hereinafter, it is assumed that i and j are integers of 2 or more, m is an integer of 1 or more and i or less, and n is an integer of 1 or more and j or less.

[0068] <1. First Embodiment>

[0069] <1.1 Overall Configuration>

[0070] Figure 2 This is a block diagram showing the overall configuration of the organic EL display device according to the first embodiment. As Figure 2 shown, the organic EL display device includes a host 100, a display control circuit 200, a source driver (data signal line driver circuit) 300, a gate driver (scan signal line driver circuit) 400, an emission driver (light emission control line driver circuit) 500, a display unit 600, and a proximity sensor 700. In addition, in this embodiment, a gate driver 400 and an emission driver 500 are formed in the organic EL panel 6 including the display unit 600. That is, the gate driver 400 and the emission driver 500 are monolithic. However, a configuration in which the gate driver 400 and the emission driver 500 are not monolithic can also be adopted.

[0071] In the display unit 600, i data signal lines D(1) to D(i) and (j + 1) scan signal lines SCAN(0) to SCAN(j) orthogonal to them are provided. Further, in the display unit 600, j emission control lines EM(1) to EM(j) are provided in a one-to-one correspondence with j scan signal lines SCAN(1) to SCAN(j) other than the scan signal line SCAN(0). The scan signal lines SCAN(0) to SCAN(j) and the emission control lines EM(1) to EM(j) are parallel to each other. Moreover, in the display unit 600, i×j pixel circuits 60 are provided corresponding to the intersection points of the i data signal lines D(1) to D(i) and the j scan signal lines SCAN(1) to SCAN(j). By providing the i×j pixel circuits 60 in this way, an i-column×j-row pixel matrix is formed in the display unit 600. In addition, hereinafter, the scan signals respectively supplied to the (j + 1) scan signal lines SCAN(0) to SCAN(j) may also be denoted by the reference numerals SCAN(0) to SCAN(j), the emission control signals respectively supplied to the j emission control lines EM(1) to EM(j) may also be denoted by the reference numerals EM(1) to EM(j), and the data signals respectively supplied to the i data signal lines D(1) to D(i) may also be denoted by the reference numerals D(1) to D(i).

[0072] In addition, power supply lines (not shown) common to all the pixel circuits 60 are provided in the display unit 600. More specifically, a power supply line for supplying a high-level power supply voltage ELVDD for driving the organic EL element (hereinafter, referred to as "high-level power supply line"), a power supply line for supplying a low-level power supply voltage ELVSS for driving the organic EL element (hereinafter, referred to as "low-level power supply line"), and a power supply line for supplying an initialization voltage Vini (hereinafter, referred to as "initialization power supply line") are provided. In addition, the high-level power supply line is denoted by the same reference numeral ELVDD as the high-level power supply voltage, the low-level power supply line is denoted by the same reference numeral ELVSS as the low-level power supply voltage, and the initialization power supply line is denoted by the same reference numeral Vini as the initialization voltage. The high-level power supply voltage ELVDD, the low-level power supply voltage ELVSS, and the initialization voltage Vini are supplied from a power supply circuit (not shown). In the present embodiment, the first power supply line is realized by the high-level power supply line ELVDD, and the second power supply line is realized by the low-level power supply line ELVSS.

[0073] In addition, as described later, in the present embodiment, two adjacent light emission control lines EM are grouped together, and the same waveform of light emission control signals is provided to the two light emission control lines EM in the same group. Therefore, the number of light emission control lines EM in the display unit 600 can also be set to (j / 2), and one light emission control line EM is branched into two light emission control lines EM near the pixel circuit 60.

[0074] Hereinafter, the operation of each component shown will be described. The host computer 100 supplies the image data DAT and the timing signal group (horizontal synchronization signal, vertical synchronization signal, etc.) TG to the display control circuit 200. In addition, the host computer 100 controls the operation of the proximity sensor 700 (for example, controls the emission timing of the IR light), and receives the result data obtained by sensing (data indicating whether an object exists at the proximity position) from the proximity sensor 700. Figure 2 The display control circuit 200 receives the image data DAT and the timing signal group TG transmitted from the host computer 100, and outputs a digital video signal DV, a source control signal SCTL for controlling the operation of the source driver 300, a gate control signal GCTL for controlling the operation of the gate driver 400, and a transmitter driver control signal EMCTL for controlling the operation of the transmitter driver 500. The source control signal SCTL includes a source start pulse signal, a source clock signal, a latch strobe signal, and the like. The gate control signal GCTL includes a gate start pulse signal, a gate clock signal, and the like. The transmitter driver control signal EMCTL includes a transmitter start pulse signal, a transmitter clock signal, and the like.

[0075] The source driver 300 is connected to the i data signal lines D(1) to D(i). The source driver 300 receives the digital video signal DV and the source control signal SCTL output from the display control circuit 200, and applies data signals to the i data signal lines D(1) to D(i). The source driver 300 includes an i-bit shift register (not shown), a sampling circuit, a latch circuit, and i D / A converters, etc. The shift register has i registers connected in cascade. The shift register sequentially transfers the pulse of the source start pulse signal supplied to the register of the first stage from the input end to the output end based on the source clock signal. Corresponding to the transfer of this pulse, sampling pulses are output from each stage of the shift register. The sampling circuit stores the digital video signal DV based on this sampling pulse. The latch circuit takes in and holds the digital video signal DV of one row amount stored in the sampling circuit according to the latch strobe signal. The D / A converters are provided corresponding to the respective data signal lines D(1) to D(i). The D / A converters convert the digital video signal DV held in the latch circuit into an analog voltage. This converted analog voltage is applied as a data signal to all the data signal lines D(1) to D(i) all at once.

[0076] The source driver 300 is connected to the i data signal lines D(1) to D(i). The source driver 300 receives the digital video signal DV and the source control signal SCTL output from the display control circuit 200, and applies data signals to the i data signal lines D(1) to D(i). The source driver 300 includes an i-bit shift register (not shown), a sampling circuit, a latch circuit, and i D / A converters, etc. The shift register has i registers connected in cascade. The shift register sequentially transfers the pulse of the source start pulse signal supplied to the register of the first stage from the input end to the output end based on the source clock signal. Corresponding to the transfer of this pulse, sampling pulses are output from each stage of the shift register. The sampling circuit stores the digital video signal DV based on this sampling pulse. The latch circuit takes in and holds the digital video signal DV of one row amount stored in the sampling circuit according to the latch strobe signal. The D / A converters are provided corresponding to the respective data signal lines D(1) to D(i). The D / A converters convert the digital video signal DV held in the latch circuit into an analog voltage. This converted analog voltage is applied as a data signal to all the data signal lines D(1) to D(i) all at once.

[0077] The gate driver 400 is connected to (j + 1) scan signal lines SCAN(0) to SCAN(j). The gate driver 400 is composed of a shift register, a logic circuit, etc. The gate driver 400 drives the (j + 1) scan signal lines SCAN(0) to SCAN(j) based on the gate control signal GCTL output from the display control circuit 200.

[0078] The emission driver 500 is connected to j light emission control lines EM(1) to EM(j). The emission driver 500 is composed of a shift register, a logic circuit, etc. The emission driver 500 drives the j light emission control lines EM(1) to EM(j) based on the emission driver control signal EMCTL output from the display control circuit 200.

[0079] The proximity sensor 700 detects the presence or absence of an object at a position close to the organic EL display device. In addition, details of the proximity sensor 700 will be described later.

[0080] As described above, the i data signal lines D(1) to D(i), the (j + 1) scan signal lines SCAN(0) to SCAN(j), and the j light emission control lines EM(1) to EM(j) are driven, so that an image based on the image data DAT is displayed on the display unit 600. In addition, it is determined whether there is an object at a position close to the organic EL display device by the detection of the proximity sensor 700.

[0081] <1.2 Proximity Sensor>

[0082] Figure 3 is a diagram for explaining the position where the proximity sensor 700 is provided. In addition, in Figure 3 the dashed line marked with the reference numeral 65 indicates the housing of the organic EL display device. The proximity sensor 700 is provided on the back surface of the display unit 600 on one end side in the extending direction of the data signal lines D(1) to D(i). Since the proximity sensor 700 is configured in this way, in the present embodiment, in Figure 4 the area indicated by the arrow marked with the reference numeral 601 becomes the IR light irradiation area. Here, it is assumed that the areas of the first to sixth rows in the display unit 600 are the IR light irradiation areas 601.

[0083] Figure 5 is a block diagram showing the functional configuration of the proximity sensor 700. As Figure 5As shown, the proximity sensor 700 includes a control unit 70, a light emitting unit 72, a light receiving unit 74, and an AD conversion unit 76. The light emitting unit 72 emits IR light (infrared light) from the back surface of the display unit 600. The light emitting unit 72 is constituted by, for example, an infrared LED, and emits IR light upon receiving supply of current from the control unit 70. The light receiving unit 74 receives the reflected light of the IR light emitted from the light emitting unit 72. The light receiving unit 74 is constituted by, for example, a photodiode, and generates a measurement current corresponding to the amount of received light. The AD conversion unit 76 performs AD conversion based on this measurement current and outputs a digital signal. The control unit 70 controls the emission timing of the IR light from the light emitting unit 72. Specifically, the control unit 70 supplies a prescribed current to the light emitting unit 72 at the timing of causing the light emitting unit 72 to emit IR light. Further, the control unit 70 determines whether an object exists at a position close to the organic EL display device based on the digital signal output from the AD conversion unit 76.

[0084] In addition, two or more proximity sensors 700 may be provided in the organic EL display device. However, also in such a case, it is assumed that only one proximity sensor 700 emits IR light.

[0085] <1.3 Pixel Circuit and Light Shielding Portion>

[0086] <1.3.1 Configuration of Pixel Circuit>

[0087] Next, the configuration of the pixel circuit 60 in the display unit 600 will be described. Figure 1 FIG. is a circuit diagram showing the configuration of the pixel circuit 60 at the n-th row and the m-th column. This pixel circuit 60 includes one organic EL element (organic light emitting diode) 61 as a display element (a display element driven by current), seven transistors (typically thin film transistors) T1 to T7 (a first initialization transistor T1, a threshold voltage compensation transistor T2, a write control transistor T3, a drive transistor T4, a power supply control transistor T5, a light emission control transistor T6, a second initialization transistor T7), and one holding capacitor Ca. The holding capacitor Ca is a capacitive element including two electrodes (a first electrode and a second electrode). The transistors T1 to T7 are P-channel type transistors. The first initialization transistor T1 and the threshold voltage compensation transistor T2 have a double gate structure in which two transistors are connected in series. By adopting such a double gate structure, an effect of improving the breakdown voltage of the transistor or reducing the cut-off current can be obtained.

[0088] Regarding Figure 1 For the configuration shown, the node connected to the first conduction terminal of the first initialization transistor T1, the second conduction terminal of the threshold voltage compensation transistor T2, the control terminal of the drive transistor T4, and the second electrode of the holding capacitor Ca is referred to as the “control node”. The control node is denoted by the reference numeral NG.

[0089] In addition, Figure 1 The configuration shown is an example and is not limited thereto. For example, a pixel circuit composed only of N-channel transistors can also be adopted, and a pixel circuit in which P-channel transistors and N-channel transistors are mixed can also be adopted. In addition, the first initialization transistor T1 and the threshold voltage compensation transistor T2 may not have a double-gate structure. In addition, for example, a configuration without the second initialization transistor T7 among the seven transistors can also be adopted.

[0090] For the first initialization transistor T1, its control terminal is connected to the scan signal line SCAN(n - 1) of the (n - 1)-th row, the first conduction terminal is connected to the control node NG, and the second conduction terminal is connected to the initialization power supply line Vini. For the threshold voltage compensation transistor T2, its control terminal is connected to the scan signal line SCAN(n) of the n-th row, the first conduction terminal is connected to the second conduction terminal of the driving transistor T4 and the first conduction terminal of the light emission control transistor T6, and the second conduction terminal is connected to the control node NG. For the write control transistor T3, its control terminal is connected to the scan signal line SCAN(n) of the n-th row, the first conduction terminal is connected to the data signal line D(m) of the m-th column, and the second conduction terminal is connected to the first conduction terminal of the driving transistor T4 and the second conduction terminal of the power supply control transistor T5. For the driving transistor T4, its control terminal is connected to the control node NG, the first conduction terminal is connected to the second conduction terminal of the write control transistor T3 and the second conduction terminal of the power supply control transistor T5, and the second conduction terminal is connected to the first conduction terminal of the threshold voltage compensation transistor T2 and the first conduction terminal of the light emission control transistor T6.

[0091] For the power supply control transistor T5, its control terminal is connected to the light emission control line EM(n) of the n-th row, the first conduction terminal is connected to the high-level power supply line ELVDD and the first electrode of the holding capacitor Ca, and the second conduction terminal is connected to the second conduction terminal of the write control transistor T3 and the first conduction terminal of the drive transistor T4. For the light emission control transistor T6, its control terminal is connected to the light emission control line EM(n) of the n-th row, the first conduction terminal is connected to the first conduction terminal of the threshold voltage compensation transistor T2 and the second conduction terminal of the drive transistor T4, and the second conduction terminal is connected to the first conduction terminal of the second initialization transistor T7 and the anode terminal (the first terminal) of the organic EL element 61. For the second initialization transistor T7, its control terminal is connected to the scan signal line SCAN(n) of the n-th row, the first conduction terminal is connected to the second conduction terminal of the light emission control transistor T6 and the anode terminal of the organic EL element 61, and the second conduction terminal is connected to the initialization power supply line Vini. For the holding capacitor Ca, its first electrode is connected to the high-level power supply line ELVDD and the first conduction terminal of the power supply control transistor T5, and the second electrode is connected to the control node NG. For the organic EL element 61, its anode terminal is connected to the second conduction terminal of the light emission control transistor T6 and the first conduction terminal of the second initialization transistor T7, and the cathode terminal (the second terminal) is connected to the low-level power supply line ELVSS.

[0092] <1.3.2 Light-shielding portion>

[0093] In the present embodiment, a light-shielding portion 81 (see Figure 1 ) is provided to prevent the channel layer of the first initialization transistor T1 from being irradiated with IR light (IR light emitted from the emission portion 72 of the proximity sensor 700). This will be described below. In addition, the first light-shielding portion is realized by the light-shielding portion 81.

[0094] Figure 6 is a layout diagram of the pixel circuit 60. Regarding Figure 6 , contact holes for electrically connecting the wiring of a certain layer and the wiring of other layers are formed in the portion of the thick circle. In addition, one of the two transistors constituting the first initialization transistor T1 having a double-gate structure is labeled with reference numeral T1a, and the other transistor is labeled with reference numeral T1b. Similarly, one of the two transistors constituting the threshold voltage compensation transistor T2 having a double-gate structure is labeled with reference numeral T2a, and the other transistor is labeled with reference numeral T2b. According to Figure 6For example, it can be understood that the scan signal line SCAN and the emission control line EM are disposed on the same layer, the initialization power supply line Vini and the high-level power supply line ELVDD extending in the left-right direction in the figure are disposed on the same layer, and the data signal line D and the high-level power supply line ELVDD extending in the up-down direction in the figure are disposed on the same layer. In addition, the layout diagram shown here is an example and is not limited thereto.

[0095] Figure 7 is Figure 6 An enlarged view of the vicinity of one first initialization transistor T1 in the layout diagram shown. The metal wiring 89 and the high-level power supply line ELVDD are disposed on the same layer. The wiring (the wiring formed by making the semiconductor layer conductive through a prescribed process) 88, the source electrode and the drain electrode of the transistor T1a, and the source electrode and the drain electrode of the transistor T1b are disposed on the same layer. In the above configuration, for example, a light-shielding portion 81 is provided in the region within the thick frame marked with the reference numeral 66. Thus, in the present embodiment, one light-shielding portion 81 is provided in an island shape corresponding to the pixel circuit 60.

[0096] Figure 8 is Figure 7 A cross-sectional view taken along line A-B of. As Figure 8 shown, an insulating film 802 and an insulating film 803 are formed on the substrate 801. A semiconductor layer 83a and a semiconductor layer 83b are formed on the insulating film 803. The semiconductor layers 83a and 83b are the same layer as the above-mentioned wiring 88 and function as a channel region or a drain and source region through processing. A gate insulating film 804 is formed so as to cover these semiconductor layers 83a and 83b and the insulating film 803, and a metal wiring serving as the scan signal line SCAN is formed on the gate insulating film 804. An insulating film 805 is formed on the metal wiring serving as the scan signal line SCAN, and a metal wiring 89 and a metal wiring serving as the high-level power supply line ELVDD are formed on the insulating film 805. And, an insulating film 806 is formed so as to cover the metal wiring 89, the metal wiring serving as the high-level power supply line ELVDD, and the insulating film 805, and an insulating film 807 is formed on the insulating film 806. Here, as Figure 8 shown, a light-shielding portion 81 is formed on the insulating film 802 in order to prevent IR light (IR light emitted from the emission portion 72 of the proximity sensor 700) from irradiating the semiconductor layers 83a and 83b. That is, the light-shielding portion 81 is provided in order to prevent IR light from irradiating the channel layer of the first initialization transistor T1.

[0097] In addition, as a member for embodying the light-shielding portion 81, for example, a plate-like metal member having the same material as the scan signal line SCAN, a plate-like resin member having the property of absorbing IR light, a plate-like resin member having the property of scattering IR light, etc. can be adopted.

[0098] In addition, on the basis of using a metal member as the member that embodies the light-shielding portion 81, a configuration can be adopted in which the metal member (light-shielding portion 81) is electrically connected to the first conduction terminal or the second conduction terminal of the first initialization transistor T1. Thus, the light-shielding portion 81 functions as a back gate electrode, and stabilization of the characteristics of the first initialization transistor T1 can be achieved.

[0099] In addition, it is preferable that the light-shielding portion 81 is provided not only for the first initialization transistor T1 within the IR light irradiation region 601 but for all the first initialization transistors T1 within the display portion 600. The reason is that homogenization of characteristics or sharing of manufacturing processes can be achieved.

[0100] Here, the reason for providing the light-shielding portion 81 only for the first initialization transistor T1 among the seven transistors T1 to T7 within the pixel circuit 60 will be described. The organic EL display device according to the present embodiment includes a proximity sensor 700. In order to realize the sensing of the proximity sensor 700, it is necessary to transmit IR light from the back surface to the front surface of the display portion 600, and further transmit the reflected light from the front surface of the display portion 600 to the back surface (specifically, the light-receiving portion 74). Therefore, it is preferable that the aperture ratio (the ratio of the area where circuit elements or wirings are provided in the entire area of the pixel circuit 60) is high. However, in the pixel circuit of the organic EL display device, the density of transistors or wirings is significantly higher than that of the pixel circuit of the liquid crystal display device. For example, for a certain pixel circuit with a pixel density of 500 ppi, its aperture ratio is about 10%. In addition, because there are a plurality of wiring gaps (for example, 0.1 to 5.0 μm) whose sizes are close to the wavelength of IR light (for example, 940 nm), diffraction or scattering of IR light occurs. As a result, the IR light traveling from the back surface to the front surface of the display portion 600 is greatly attenuated. Based on the above situation, a configuration in which the light-shielding portion is provided for most of the pixel circuit 60 or a configuration in which the light-shielding portion is provided for all the transistors within the pixel circuit 60 cannot be adopted. In addition, when a back gate electrode is provided for a transistor, a metal electrode layer with a sufficient width is required to ensure the contact area. Therefore, the transistors for which the light-shielding portion is provided in high-definition pixels are limited. In view of the above aspects, it is preferable to provide the light-shielding portion for the transistor that has the greatest impact on the display due to the irradiation of IR light. Specifically, it is preferable to provide the light-shielding portion for the following transistor: the conduction terminal of the transistor is connected to a holding capacitor Ca that is used to hold a voltage throughout the frame period after a data signal is written to the pixel circuit 60. Therefore, as described above, the light-shielding portion 81 is provided only for the first initialization transistor T1 among the seven transistors T1 to T7 within the pixel circuit 60.

[0101] <1.3.3 LDD Structure>

[0102] As described above, an increase in the cut-off current of the first initialization transistor T1 causes a deterioration in display quality. Therefore, in order to suppress the increase in the cut-off current, an LDD structure can be adopted for the first initialization transistor T1. This will be described below. In addition, LDD is an abbreviation for "Lightly Doped Drain".

[0103] Figure 9 is a cross-sectional schematic diagram for explaining the LDD structure. The gate electrode 84 is formed on the gate insulating film 85 in the same manner as in a general structure. Below the gate insulating film 85, an LDD region 87 containing a low concentration of impurities is provided between the channel region (channel layer) 83 and the drain and source regions 86 containing a high concentration of impurities. According to this LDD structure, an effect of reducing the drain electric field and decreasing the leakage current can be obtained.

[0104] When the structure of the first initialization transistor T1 adopts the LDD structure, for example, as Figure 10 shown, a light-shielding portion 81 may be provided in such a manner that the entire channel region (channel layer) 83 is shielded from light.

[0105] Alternatively, a structure called a "single-sided LDD structure" in which only an LDD region 87 is provided on the drain side can be adopted for the first initialization transistor T1. In this case, a light-shielding portion 81 may be provided in such a manner that the entire channel region (channel layer) 83 is shielded from light, or as Figure 11 shown, a light-shielding portion 81 may be provided in such a manner that the region on the source side in the entire channel region (channel layer) 83 is shielded from light. In this way, a single-sided LDD structure in which the first initialization transistor T1 has an LDD structure only on one side of the first conduction terminal side or the second conduction terminal side can be adopted. In this case, a light-shielding portion 81 can be provided on the side of the first conduction terminal side or the second conduction terminal side that does not have an LDD structure.

[0106] <1.3.4 Operation of Pixel Circuit>

[0107] Next, the operation of the pixel circuit 60 will be described with reference to Figure 12 Here, attention is focused on the pixel circuits 60 in the n-th row and the (n + 1)-th row that are provided with the same waveform of the emission control signals EM(n) and EM(n + 1).

[0108] During the period before the moment immediately preceding time t00 (i.e., before approaching time t00), the scan signals SCAN(n-1), SCAN(n), and SCAN(n+1) are at a high level, and the light emission control signals EM(n) and EM(n+1) are at a low level. At this time, in both the pixel circuit 60 of the n-th row and the pixel circuit 60 of the (n+1)-th row, the power supply control transistor T5 and the light emission control transistor T6 are in an on state, and the organic EL element 61 emits light according to the magnitude of the drive current.

[0109] When it becomes time t00, the light emission control signals EM(n) and EM(n+1) change from a low level to a high level. As a result, in both the pixel circuit 60 of the n-th row and the pixel circuit 60 of the (n+1)-th row, the power supply control transistor T5 and the light emission control transistor T6 become in an off state. As a result, the supply of current to the organic EL element 61 is blocked, and the organic EL element 61 becomes in an extinguished state.

[0110] When it becomes time t01, the scan signal SCAN(n-1) changes from a high level to a low level. As a result, in the pixel circuit 60 of the n-th row, the first initialization transistor T1 becomes in an on state, and the gate voltage (voltage of the control node NG) of the drive transistor T4 is initialized. That is, the gate voltage of the drive transistor T4 in the pixel circuit 60 of the n-th row becomes equal to the initialization voltage Vini.

[0111] When it becomes time t02, the scan signal SCAN(n-1) changes from a low level to a high level. As a result, in the pixel circuit 60 of the n-th row, the first initialization transistor T1 becomes in an off state. In addition, at time t02, the scan signal SCAN(n) changes from a high level to a low level. As a result, in the pixel circuit 60 of the n-th row, the threshold voltage compensation transistor T2, the write control transistor T3, and the second initialization transistor T7 become in an on state. Since the threshold voltage compensation transistor T2 and the write control transistor T3 become in an on state, the data signal D(m) is supplied to the control node NG via the write control transistor T3, the drive transistor T4, and the threshold voltage compensation transistor T2. As a result, the holding capacitor Ca is charged. In addition, since the second initialization transistor T7 becomes in an on state, the anode voltage of the organic EL element 61 is initialized based on the initialization voltage Vini. In the pixel circuit 60 of the (n+1)-th row, since the scan signal SCAN(n) changes from a high level to a low level, the first initialization transistor T1 becomes in an on state, and the gate voltage of the drive transistor T4 is initialized. That is, the gate voltage of the drive transistor T4 in the pixel circuit 60 of the (n+1)-th row becomes equal to the initialization voltage Vini.

[0112] When it becomes time t03, the scan signal SCAN(n) changes from a low level to a high level. As a result, in the pixel circuit 60 of the n-th row, the threshold voltage compensation transistor T2, the write control transistor T3, and the second initialization transistor T7 become in an off state. At this time, in the pixel circuit 60 of the (n + 1)-th row, the first initialization transistor T1 becomes in an off state. Further, at time t03, the scan signal SCAN(n + 1) changes from a high level to a low level. As a result, in the pixel circuit 60 of the (n + 1)-th row, the threshold voltage compensation transistor T2, the write control transistor T3, and the second initialization transistor T7 become in an on state. Since the threshold voltage compensation transistor T2 and the write control transistor T3 become in an on state, the data signal D(m) is supplied to the control node NG via the write control transistor T3, the drive transistor T4, and the threshold voltage compensation transistor T2. As a result, the holding capacitor Ca is charged. Further, since the second initialization transistor T7 becomes in an on state, the anode voltage of the organic EL element 61 is initialized based on the initialization voltage Vini.

[0113] When it becomes time t04, the scan signal SCAN(n + 1) changes from a low level to a high level. As a result, in the pixel circuit 60 of the (n + 1)-th row, the threshold voltage compensation transistor T2, the write control transistor T3, and the second initialization transistor T7 become in an off state. Further, at time t04, the light emission control signals EM(n) and EM(n + 1) change from a high level to a low level. As a result, in both the pixel circuit 60 of the n-th row and the pixel circuit 60 of the (n + 1)-th row, the power supply control transistor T5 and the light emission control transistor T6 become in an on state, and a drive current corresponding to the charging voltage of the holding capacitor Ca is supplied to the organic EL element 61. As a result, in both the pixel circuit 60 of the n-th row and the pixel circuit 60 of the (n + 1)-th row, the organic EL element 61 emits light according to the magnitude of the drive current. After that, during the entire period until the next light emission control signals EM(n) and EM(n + 1) change from a low level to a high level, in both the pixel circuit 60 of the n-th row and the pixel circuit 60 of the (n + 1)-th row, the organic EL element 61 emits light.

[0114] <1.4 Control of the irradiation timing of IR light (infrared light)>

[0115] Figure 13 is a timing chart for explaining the irradiation timing of IR light. According to Figure 13 it can be understood that, in the present embodiment, the light emission control signals having the same waveform are provided to every two light emission control lines EM. That is, the light emission control signals having the same waveform are provided to two adjacent light emission control lines EM as a group.

[0116] As described above, in the present embodiment, in the pixel circuit 60 of the n-th row, the gate voltage of the driving transistor T4 (the voltage of the control node NG) is initialized during the period when the scan signal SCAN(n - 1) is at a low level (refer to Figure 1 and Figure 12 ). Further, as described above, in the present embodiment, the regions of the first to sixth rows within the display unit 600 are the IR light irradiation regions 601. Regarding this IR light irradiation region 601, it can be understood from the waveform of the scan signal SCAN shown in Figure 13 that in the pixel circuit 60 of the first row, the gate voltage of the driving transistor T4 is initialized during the period from time t11 to time t12, and in the pixel circuit 60 of the sixth row, the gate voltage of the driving transistor T4 is initialized during the period from time t16 to time t17. Further, according to Figure 13 , it can be understood that the writing of the data signal to the pixel circuits 60 within the IR light irradiation region 601 is performed sequentially row by row during the period from time t12 to time t18.

[0117] Here, in the present embodiment, the gate voltage of the driving transistor T4 is not initialized in all the pixel circuits 60 within the IR light irradiation region 601, and IR light is irradiated (IR light is emitted from the emission unit 72 of the proximity sensor 700) during the period when the data signal is not written in all the pixel circuits 60 within the IR light irradiation region 601. That is, in Figure 13 , IR light is irradiated during at least a part of the period indicated by the arrows labeled with reference numerals P1, P2, and P3. Regarding this, during the period indicated by the arrows labeled with reference numerals P1, P2, and P3, even if the conduction current of the transistor without the light shielding portion increases due to the irradiation of the IR light, the influence of the increase in the conduction current on the display is small. Therefore, by irradiating the IR light during such a period, the difference in the luminance characteristics between the pixels within the IR light irradiation region 601 and the pixels outside the IR light irradiation region 601 is suppressed from becoming large, and the degradation of the display quality caused by the irradiation of the IR light is suppressed.

[0118] As described above, the emission unit 72 of the proximity sensor 700 emits IR light during the period when the first initialization transistor T1 in all the pixel circuits 60 within the IR light irradiation region 601 is in the cut-off state and the writing control transistor T3 in all the pixel circuits 60 within the IR light irradiation region 601 is in the cut-off state.

[0119] In addition, in the present embodiment, two light emission control lines EM are set as a group. However, the number of light emission control lines EM equal to the number of rows included in the IR light irradiation region 601 may be set as a group. In the above example where the region of the first to sixth rows in the display unit 600 is the IR light irradiation region 601, six light emission control lines EM may be set as a group, and the same waveform light emission control signal may be provided to the six light emission control lines EM in the same group. In addition, for each row, a period during which emission is turned off is provided for writing a data signal. However, a period during which emission is turned off for the purpose of dimming or the like, which is different from when writing a data signal, may be provided.

[0120] <1.5 Effect>

[0121] According to the present embodiment, in the organic EL display device, the light shielding portion 81 is provided to prevent the IR light from irradiating the channel layer of the first initialization transistor T1 in the pixel circuit 60. Therefore, even if IR light is emitted from the proximity sensor 700 for sensing, the IR light does not irradiate the channel layer of the first initialization transistor T1, and thus the cut-off current of the first initialization transistor T1 does not increase. Accordingly, the variation in the gate voltage (voltage of the control node NG) of the driving transistor T4 caused by the irradiation of the IR light is suppressed, and thus the degradation of the display quality is suppressed. In addition, since the light shielding portion 81 is provided only for one transistor out of the seven transistors in the pixel circuit 60, the decrease in the aperture ratio is suppressed and the accuracy of sensing is maintained. As described above, in the organic EL display device provided with the proximity sensor, the degradation of the display quality caused by the irradiation of the IR light is suppressed as compared with the prior art.

[0122] In addition, according to the present embodiment, the first initialization transistor T1 and the threshold voltage compensation transistor T2 have a double gate structure. Therefore, compared with the case of adopting a general structure, the cut-off currents of the first initialization transistor T1 and the threshold voltage compensation transistor T2 become smaller. Thereby, the variation in the gate voltage of the driving transistor T4 is effectively suppressed, and the degradation of the display quality is effectively suppressed. In addition, by adopting the LDD structure for the structure of the first initialization transistor T1, the cut-off current can be further reduced.

[0123] <2. Second Embodiment>

[0124] The second embodiment of the present invention will be described. In addition, mainly only the differences from the above-described first embodiment will be described below.

[0125] <2.1 Configuration>

[0126] In the above-described first embodiment, the light shielding portion 81 is provided corresponding only to the first initialization transistor T1 out of the seven transistors in the pixel circuit 60. In contrast, in the present embodiment, asFigure 14 As shown, in addition to providing the light-shielding portion 81 corresponding to the first initialization transistor T1, a light-shielding portion 82 corresponding to the threshold voltage compensation transistor T2 is also provided. Further, the first conduction terminal of the first initialization transistor T1 is electrically connected to the second electrode of the holding capacitor Ca. Additionally, the second conduction terminal of the threshold voltage compensation transistor T2 is also electrically connected to the second electrode of the holding capacitor Ca. Thus, in the present embodiment, light-shielding portions are provided for transistors (the first initialization transistor T1 and the threshold voltage compensation transistor T2) whose one conduction terminal is connected to the second electrode of the holding capacitor Ca. As described above, in the organic EL display device according to the present embodiment, there are provided: a light-shielding portion 81 that prevents IR light from irradiating the channel layer of the first initialization transistor T1 in the pixel circuit 60; and a light-shielding portion 82 that prevents IR light from irradiating the channel layer of the threshold voltage compensation transistor T2 in the pixel circuit 60. Considering the manufacturing process, it is preferable that the light-shielding portion 81 and the light-shielding portion 82 are formed of the same material on the same layer. Further, the first light-shielding portion is realized by the light-shielding portion 81, and the second light-shielding portion is realized by the light-shielding portion 82.

[0127] Figure 15 and Figure 16 is Figure 6 an enlarged view near one threshold voltage compensation transistor T2 in the layout diagram shown. In Figure 15 a first example of the arrangement position of the light-shielding portion 82 is shown, and in Figure 16 a second example of the arrangement position of the light-shielding portion 82 is shown. In the first example, the light-shielding portion 82 is provided in the region within the thick frame marked with reference numeral 67 in Figure 15 . That is, the light-shielding portion 82 is L-shaped to match the shape of the wiring (including the wiring of the semiconductor layer) 88 at the portion where the threshold voltage compensation transistor T2 exists. In the second example, the light-shielding portion 82 is provided in the region within the thick frame marked with reference numeral 68 in Figure 16 . That is, the light-shielding portion 82 has a rectangular shape.

[0128] Similar to the structure of the first initialization transistor T1, for the structure of the threshold voltage compensation transistor T2, a general LDD structure or a single-sided LDD structure can also be adopted. When the general LDD structure is adopted for the structure of the threshold voltage compensation transistor T2, the light-shielding portion 82 may be provided in such a manner that the entire channel region (channel layer) is shielded from light. When the single-sided LDD structure is adopted for the structure of the threshold voltage compensation transistor T2, the light-shielding portion 82 may be provided in such a manner that the entire channel region is shielded from light, or may be provided in such a manner that the region on the source side in the entire channel region (channel layer) is shielded from light.

[0129] <2.2 Effects>

[0130] ​According to the present embodiment, it is possible to prevent the channel layers of the first initialization transistor T1 and the threshold voltage compensation transistor T2 in the pixel circuit 60 from being irradiated with IR light. Therefore, even if IR light is emitted from the proximity sensor 700 for sensing, the cutoff currents of the first initialization transistor T1 and the threshold voltage compensation transistor T2 do not increase. Thus, compared with the first embodiment described above, the variation in the gate voltage (voltage of the control node NG) of the driving transistor T4 caused by the irradiation of IR light is effectively suppressed. That is, the degradation of the display quality caused by the irradiation of IR light is effectively suppressed.

[0131] <3. Others>

[0132] In the above embodiments, an organic EL display device has been exemplified, but the present invention is not limited thereto. If it is a display device that includes a proximity sensor and uses a current-driven display element, the present invention can also be applied to an inorganic EL display device, a QLED (Quantum Dot Light Emitting Diodes) display device, and the like.

[0133] Explanation of Reference Numerals

[0134] 6… Organic EL panel

[0135] 60… Pixel circuit

[0136] 61… Organic EL element

[0137] 72… (Emitting part of the proximity sensor)

[0138] 74… (Light receiving part of the proximity sensor)

[0139] 81, 82… Light shielding part

[0140] 300… Source driver (data signal line driving circuit)

[0141] 400… Gate driver (scan signal line driving circuit)

[0142] 500… Emission driver (light emission control line driving circuit)

[0143] 600… Display unit

[0144] 601… IR light irradiation area

[0145] 700… Proximity sensor

[0146] D(1)~D(i)… Data signal line, data signal

[0147] EM(1)~EM(j)… Light emission control line, light emission control signal

[0148] SCAN(1) to SCAN(j)… Scan signal lines, scan signals

[0149] NG… Control node

[0150] T1… First initialization transistor

[0151] T2… Threshold voltage compensation transistor

[0152] T3… Write control transistor

[0153] T4… Driving transistor

[0154] T5… Power supply control transistor

[0155] T6… Light emission control transistor

[0156] T7… Second initialization transistor.

Claims

1. A display device includes a pixel circuit including a display element driven by current, characterized in that, Comprising: A display unit, including: the pixel circuits arranged in multiple rows and multiple columns; a plurality of data signal lines for supplying data signals to the pixel circuits in corresponding columns; a plurality of scan signal lines for controlling the writing of the data signals into the pixel circuits in corresponding rows; a plurality of light emission control lines for controlling whether to supply current to the display elements included in the pixel circuits in corresponding rows; a first power supply line for supplying a high-level power supply voltage; a second power supply line for supplying a low-level power supply voltage; And an initialization power supply line for supplying an initialization voltage; and A proximity sensor, including an emitting portion for emitting infrared light from the back surface of the display unit and a light receiving portion for receiving the reflected light of the infrared light, Each pixel circuit includes: A control node; The display element having a first terminal and a second terminal connected to the second power supply line; A driving transistor having a control terminal connected to the control node, a first conduction terminal, and a second conduction terminal, and being arranged in series with the display element; A light emission control transistor having a control terminal connected to one of the plurality of light emission control lines, a first conduction terminal, and a second conduction terminal, and being arranged in series with the display element; A holding capacitor having one end connected to the first power supply line and the other end connected to the control node; A writing control transistor having a control terminal connected to one of the plurality of scan signal lines, a first conduction terminal connected to one of the plurality of data signal lines, and a second conduction terminal connected to the first conduction terminal of the driving transistor; A threshold voltage compensation transistor having a control terminal connected to one of the plurality of scan signal lines, a first conduction terminal connected to the second conduction terminal of the driving transistor, and a second conduction terminal connected to the control node; And A first initialization transistor having a control terminal connected to one of the plurality of scan signal lines, a first conduction terminal connected to the control node, and a second conduction terminal connected to the initialization power supply line, A first light-shielding portion for preventing the infrared light from irradiating the channel layer of the first initialization transistor is provided, The emitting portion emits the infrared light during a period when the first initialization transistors in all the pixel circuits within the infrared light irradiation region irradiated by the infrared light are in an off state and the writing control transistors in all the pixel circuits within the infrared light irradiation region are in an off state.

2. The display device according to claim 1, wherein The light-shielding portion for preventing the infrared light from irradiating the channel layer of the transistors included in the pixel circuit is the first light-shielding portion provided in an island shape corresponding to the pixel circuit and only one.

3. The display device according to claim 1, wherein A second light-shielding portion for preventing the infrared light from irradiating the channel layer of the threshold voltage compensation transistor is provided.

4. The display device according to claim 3, wherein The first light-shielding portion and the second light-shielding portion are formed of the same material on the same layer.

5. The display device according to any one of claims 1 to 4, characterized in that For the entire display portion, the first light-shielding portion is provided for each pixel circuit.

6. The display device according to any one of claims 1 to 4, characterized in that The first initialization transistor has an LDD structure.

7. The display device according to claim 6, characterized in that The first initialization transistor has an LDD structure only on one side of the first conduction terminal side or the second conduction terminal side, The first light-shielding portion is provided on the side that does not have an LDD structure among the first conduction terminal side or the second conduction terminal side.

8. The display device according to any one of claims 1 to 4, characterized in that The first initialization transistor has a double-gate structure composed of two transistors connected in series.

9. The display device according to any one of claims 1 to 4, characterized in that The first light-shielding portion is a metal member and is electrically connected to the first conduction terminal or the second conduction terminal of the first initialization transistor.

10. The display device according to any one of claims 1 to 4, characterized in that The first light-shielding portion is a plate-shaped metal member made of the same material as the plurality of scan signal lines.

11. The display device according to any one of claims 1 to 4, characterized in that The first light-shielding portion is a plate-shaped resin member having the property of absorbing the infrared light.

12. The display device according to any one of claims 1 to 4, characterized in that The first light-shielding portion is a plate-shaped resin member having the property of scattering the infrared light.

13. The display device according to any one of claims 1 to 4, characterized in that The first conduction terminal of the light emission control transistor is connected to the second conduction terminal of the drive transistor, The second conduction terminal of the light emission control transistor is connected to the first terminal of the display element, Each pixel circuit includes a power supply control transistor, and the power supply control transistor has: a control terminal connected to one of the plurality of light emission control lines; a first conduction terminal connected to the first power supply line; and a second conduction terminal connected to the first conduction terminal of the drive transistor.

14. The display device according to claim 13, characterized in that Each pixel circuit includes a second initialization transistor, and the second initialization transistor has: A control terminal connected to one of the plurality of scan signal lines; a first conduction terminal connected to the first terminal of the display element; and a second conduction terminal connected to the initialization power supply line.

Images