transistor

Abstract

Even with a reduced current supplied to the electroluminescent element, the pixel area can be increased. Suppress. [Solution] A switch transistor, a first drive transistor, and an electroluminescent A first drive transistor and an electroluminescent element are placed between the first drive transistor and the electroluminescent element. It comprises two drive transistors. The gate of the second drive transistor is at the power supply potential. It is given. Also, the second drive is provided by the first drive transistor and the second drive transistor. Controlling the drain current of the dynamic transistor and the current value supplied to the electroluminescent element. Control.

Description

[Technical Field]

[0001] One aspect of the present invention relates to a display device, and also to an electronic device. [Background technology]

[0002] In recent years, technological developments related to increasing the resolution of display devices have been progressing.

[0003] Examples of the above-mentioned display devices include electroluminescent display devices (also known as EL display devices). Examples include (see, for example, Patent Document 1). The above EL display device is electroluminescent A light-emitting diode (also called an EL element) and a drive transistor that controls the amount of current supplied to the EL element. It is equipped with Ta and.

[0004] To make the above EL display device higher resolution, one can increase the number of pixels and thus the resolution. In EL display devices, the aim is to reduce variations in brightness characteristics between multiple pixels, and It is necessary to increase the operating speed of the drive circuit. Therefore, the electric field that constitutes the EL display device As an effect transistor, it has high field-effect mobility and low variation in electrical characteristics. It is preferable to use a DISTA, for example, an electric channel formed in a single-crystal silicon layer. It is preferable to use a field-effect transistor.

[0005] On the other hand, for a given panel size, increasing the number of pixels increases the area per pixel. It gets smaller. The amount of current required for an EL element is determined by its area. Therefore, the pixel area As the size of the EL element decreases, the area of ​​the EL element also decreases, so it is necessary to reduce the amount of current supplied to the EL element. There is a way to reduce the amount of current supplied to the EL element, for example, by changing the drive transistor's soaring power. The current flowing between the source and the drain (also referred to as the drain current) should be reduced.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In a conventional display device, with the increase in high definition, by reducing the amount of current supplied to the EL element, there was a problem that the pixel area would increase. Therefore, the high definition of the display device was hindered from being achieved. The reason for this will be explained below.

[0008] In a conventional display device, without increasing the manufacturing process and while maintaining the characteristics of other field-effect transistors (such as field-effect mobility, threshold voltage, or electrical characteristic variations, etc.), to reduce the drain current of the driving transistor, it is necessary to increase the channel length of the driving transistor and narrow the channel width. Since the channel width can only be narrowed to a certain value due to the limit of processing accuracy, it is necessary to increase the channel length of the driving transistor to reduce the drain current of the driving transistor. When the channel length of the driving transistor increases, naturally the pixel area will increase. Therefore, it is difficult to increase the channel length of the driving transistor while the area per pixel is decreasing due to high definition. current. area expands. In view of the above problems, in one aspect of the present invention, one of the problems is to suppress the expansion of the pixel area even when the current supplied to the EL element is reduced.

[0009] In view of the above problems, in one aspect of the present invention, one of the problems is to suppress the expansion of the pixel area even when the current supplied to the EL element is reduced. [[ID=​

Means for Solving the Problem

[0010] In one aspect of the present invention, a pixel circuit of a display device is configured by a switching transistor, a first driving transistor, an EL element, and a second driving transistor provided between the first driving transistor and the EL element.

[0011] The first driving transistor has a gate to which the potential of a data signal is applied via the switching transistor, and controls the value of the drain current according to the potential of the data signal.

[0012] The second driving transistor is formed in the same process as the first driving transistor and has the same conductivity type. Also, a power supply potential is applied to the gate of the second driving transistor. The above power supply potential is preferably a constant potential.

[0013] The first driving transistor and the second driving transistor have a function of controlling the current value supplied to the EL element.

[0014] Furthermore, in one aspect of the present invention, when the first driving transistor is in the linear region, the first driving transistor and the second driving transistor control the drain current of the second driving transistor in the saturation region so that the maximum value of the drain current of the second driving transistor, denoted as Id when the first driving transistor is in the linear region, satisfies the following formula (1). max

[0015]

Equation

[0016] However, in formula (1), L1 is the channel length of the first driving transistor, and L2 is the second driving​​​​​​​​​ Transistor channel length, W is the channel width of the first drive transistor, μ is the first drive The field-effect mobility (Vg) of a transistor is the gate-source of the first driving transistor. The voltage between Vth and Cox is the threshold voltage of the first drive transistor. This represents the sum of the gate capacitance of the first transistor and the gate capacitance of the second drive transistor.

[0017] As described above, in one aspect of the present invention, the first drive transistor and the second drive transistor Therefore, the second drive transistor in the saturation region satisfies the above equation (1). The value of the drain current is controlled to reduce the current supplied to the EL element.

[0018] Furthermore, in one aspect of the present invention, a display device equipped with the above-mentioned pixel circuit is provided in the housing of an electronic device. It forms a panel that can be kicked. [Effects of the Invention]

[0019] In one aspect of the present invention, the first drive transistor and the second drive transistor are used to perform the second By reducing the drain current of the drive transistor, the current supplied to the EL element is reduced. Also, the sum of the channel length of the first drive transistor and the channel length of the second drive transistor The channel length can be reduced to less than that of conventional drive transistors. Therefore, the pixel area can be increased. This can suppress it. [Brief explanation of the drawing]

[0020] [Figure 1] A circuit diagram used to explain the circuit configuration of a display device. [Figure 2] A circuit diagram illustrating the circuit configuration of the comparative example display device. [Figure 3]This figure shows the calculated change in drain current when the source and drain voltages of a transistor are changed. [Figure 4] This figure shows the calculated change in drain current when the source and drain voltages of a transistor are changed. [Figure 5] Planar schematic and cross-sectional schematic diagrams showing examples of active matrix substrate structures. [Figure 6] A schematic cross-sectional diagram showing an example of the structure of a display device. [Figure 7] A block diagram showing an example configuration of a display device. [Figure 8] A diagram used to explain electronic devices. [Modes for carrying out the invention]

[0021] Examples of embodiments of the present invention will be described below. Note that these examples will not deviate from the spirit and scope of the present invention. It is easy for a person skilled in the art to change the content of the embodiment without modification. Therefore, for example, this invention The details are not limited to those described in the embodiments below.

[0022] Furthermore, the contents of each embodiment can be combined with each other as appropriate. The contents can be substituted for each other as appropriate.

[0023] Furthermore, ordinal numbers such as 1st, 2nd, etc. are added to avoid confusion of the constituent elements, and each constituent element The number is not limited to ordinal numbers.

[0024] (Embodiment 1) In this embodiment, an example of a display device according to one aspect of the present invention will be described with reference to Figures 1 to 7. ru.

[0025] First, the circuit configuration of the pixel circuit in the display device of this embodiment will be explained using Figure 1. Figure 1 is a circuit diagram showing the circuit configuration of the pixel circuit.

[0026] As shown in Figure 1, the display device of this embodiment is a field-effect transistor, which is a switched transistor. A transistor 110, a first drive transistor 111 which is a field-effect transistor, and a capacitor Element 130, EL element (electroluminescent element) 120, and field effect transistor It includes a second drive transistor 112, which is a ta.

[0027] One of the source and drain of the switch transistor 110 is connected to a data signal line DL. The potential of the data signal is supplied by the switch transistor 110. The gate signal potential is supplied to the terminal via the gate signal line GL. By making the ZISTA 110 a double-gate transistor, the transistor's off-voltage is The current can be reduced, but is not limited to this. Also, in Figure 1, the switch transistor 110 While this is an N-channel transistor, it is not limited to this, and a P-channel transistor is also an N-channel transistor. It may be present. The switch transistor 110 is the data of the data signal held in the pixel circuit. It has a function to control whether or not to rewrite the data.

[0028] One of the source and drain of the first drive transistor 111 is connected to the first power supply line P The first power supply potential VP1 is supplied via SL1. Also, the first drive transistor 11 The gate of 1 is connected to the other side of the source and drain of the switch transistor 110. The gate and switch transistor of the first drive transistor 111 are connected. The source and drain of the 110 do not necessarily have to be directly connected. The gate potential of the drive transistor 111 is controlled by a data signal. That would be fine. Also, the first drive transistor 111 is not limited to a P-channel type transistor. It is not specified and may be an N-channel transistor. The first drive transistor 111 is It has a function to control the amount of current supplied to the EL element 120.

[0029] A capacitive potential is applied to one of the pair of electrodes of the capacitive element 130 via the capacitance line CsL. Furthermore, the other of the pair of electrodes of the capacitive element 130 is connected to the first drive transistor 11. It is connected to gate 1. Note that the capacitive element 130 is a MOS capacitor, and the capacitance line CsL and the A power line PSL1 is connected, and a first power potential VP1 is supplied as the capacitance potential. It is not limited to this. For example, the capacitance potential is set without connecting the capacitance line CsL and the first power line PSL1. A potential different from the first power supply potential VP1 may be applied. Also, the capacitive element 130 is not necessarily required. It is not necessary to provide it. The capacitive element 130 is used when data of the data signal is written to the pixel circuit. In this case, the retaining capacity that holds the charge accumulated in the gate of the first drive transistor 111 It functions as a quantity.

[0030] One of the anode and cathode of the EL element 120 is connected via the second power line PSL2. Then a second power supply potential VP2 is applied. Note that the EL element 120 is not limited to sequentially stacked EL elements. The EL elements are not fixed and may be stacked in reverse. The EL element 120 is a second drive transistor It has the function of emitting light with a brightness corresponding to the drain current of the TA112.

[0031] The second drive transistor 112 is formed by the same process as the first drive transistor 111. Furthermore, it is a transistor of the same conductivity type. The second drive transistor 112 has One of the source and drain of the first drive transistor 111 is the source and drain of the first drive transistor 111. It is connected to the other side. Also, the source and drain of the second drive transistor 112 The other end is connected to the other end of the anode and cathode of the EL element 120. The gate of the 2 drive transistor 112 is connected to the third power line PSL3. A power supply potential VP3 is provided. The third power supply potential VP3 is preferably a constant potential. Furthermore, if the amplitude is within a certain range, it can be considered to be a constant potential. The transistor 112 is not limited to P-channel transistors, but also N-channel transistors. This may also be the case. Furthermore, the channel length of the first drive transistor 111 may be the same as that of the second drive transistor The configuration is not limited to one longer than the channel length of the zista 112, but also includes the second drive transistor 112. Even if the channel length is longer than the channel length of the first drive transistor 111, The second drive transistor 112 has the function of controlling the amount of current supplied to the EL element 120. It has.

[0032] Next, an example of a driving method for the display device shown in Figure 1 will be described. In this case, the first power supply potential is The first power supply is set to a high potential, and the second power supply is set to a low potential.

[0033] First, the potential of the gate signal line GL is set by the potential of the gate signal, and the switch transistor Turn on 110. Also, set the potential of the data signal line DL based on the potential of the data signal. do.

[0034] At this time, the gate potential of the first drive transistor 111 is equal to the potential of the data signal. This is what happens. At this time, the drain current of the first drive transistor 111 is Id 111 Let's assume that.

[0035] Also, according to the drain current of the first drive transistor 111, the second drive transistor 112 operates in the saturation region. At this time, the drain current of the second drive transistor 112 is defined as Id 112 .

[0036] The drain current (Id 112 ) of the second drive transistor 112 in the saturation region is obtained by the following mathematical formula (2).

[0037]

Equation

[0038] In mathematical formula (2), L 112 is the channel length of the second drive transistor 112, W 112 is the channel width of the second drive transistor 112, μ 112 is the field effect mobility of the second drive transistor 112, Vg is the voltage between the gate and the source of the second drive transistor 112, Vth 112 is the threshold voltage of the second drive transistor 112, and Cox is the gate capacitance of the second drive 112 transistor 112, respectively. 112 represents the gate capacitance of the second drive transistor 112.

[0039] The drain current of the second drive transistor 112 in the saturation region can be regarded as equal to the drain current of the first drive transistor 111. That is, the luminance of the EL element 120 becomes a value corresponding to the potential of the data signal.

[0040] Even when the EL element 120 deteriorates, the second drive transistor 112 is saturated By operating within the specified region, fluctuations in the current value supplied to the EL element 120 can be suppressed.

[0041] Furthermore, in the display device of this embodiment, when the first drive transistor 111 is in the linear region, Id is the maximum value of the drain current of the second drive transistor 112 in the saturation region. 112m ax In that case, Id 112max The second drive transistor satisfies the following equation (3). The drain current of the zista 112 is controlled by the first drive transistor 111 and the second drive transistor Controlled by TA112.

[0042]

number

[0043] In formula (3), L 111 The channel length of the first drive transistor 111 is L. 112 is the second The channel length of the drive transistor 112, W 111 The first drive transistor 111 Channel width, μ 111 Vg is the field-effect mobility of the first drive transistor 111. 111 is the The voltage between the gate and source of the drive transistor 111, Vth 111 is the first drive threshold voltage of transistor 111, Cox Z The first drive transistor 111 and the second drive transistor This represents the sum of the gate capacities of the transistors 112.

[0044] The right-hand side of equation (3) above represents the first drive transistor 111 and the second drive transistor shown in Figure 1. Transistor 112 is considered together with the third drive transistor, and the third drive transistor One of the source and drain of the element is connected to the first power line PSL1, and the other is connected to the EL element. The other side of the anode and cathode of child 120 is connected to the third drive transistor. The channel length is the channel length of the first drive transistor 111 and the second drive transistor as shown in Figure 1. The third drive transistor in the saturation region, when it is the sum of the channel lengths of ZISTA 112 This is equivalent to the formula for calculating the drain current.

[0045] In the display device of this embodiment, the first drive transistor 111 and the second drive transistor The sta 112 is formed by the same process and has the same conductivity type. Therefore, the first drive The field-effect mobility and threshold voltage of the transistor 111 and the second drive transistor 112 are the same. If so, the channel length of the first drive transistor 111 and the second drive transistor The channel length of TA112, the amplitude of the data signal, and the first power supply potential VP1 to the third power supply potential V By appropriately setting the value of P3, etc., the second drive transition satisfies equation (3). The drain current of the first drive transistor 111 can be controlled. Channel length, channel length of the second drive transistor 112, amplitude of the data signal, first power supply The value of the third power potential VP3 is set according to the values ​​of the second power potential VP2 and the second power potential VP1. This controls the drain current of the second drive transistor 112 so as to satisfy equation (3). It is preferable to control it. Furthermore, if equation (3) is satisfied, the first drive transistor 111 may be operated in the saturation region.

[0046] Furthermore, the EL element 120 has a brightness corresponding to the drain current of the second drive transistor 112. It emits light. As a result, the pixel circuit enters a light-emitting state (display state). After that, it switches By turning off the transistor 110, the gate of the first drive transistor 111 is turned off. Because the potential can be maintained, the luminescence state can be sustained.

[0047] Here, the first drive transistor 111 and the second drive transistor satisfy equation (3) The channel length of ZISTA 112 will be explained in comparison with the display device of the comparative example.

[0048] First, the circuit configuration of the pixel circuit in the comparative example display device will be explained using Figure 2. Figure 2 is a circuit diagram showing the circuit configuration of the pixel circuit.

[0049] As shown in Figure 2, the comparative example display device has the first drive transistor 111 and shown in Figure 1. This configuration includes a drive transistor 211 instead of the second drive transistor 112. At this time, one of the source and drain of the drive transistor 211 is connected to the first power supply Given position VP1, the source and the other drain of the drive transistor 211 are E It is connected to the other side of the anode and cathode of the L element 120. Also, the drive transistor 21 The gate of 1 is connected to the other side of the source and drain of the switch transistor 110. Connected.

[0050] Next, in the second drive transistor 112 shown in Figure 1, the source and drain voltages (d Also called the drain voltage. The change in drain current when the voltage is changed, and the drive traction shown in Figure 2. Figure 3 shows the change in drain current when the drain voltage is changed in the inverter 211. This will be explained using Figure 4. Figures 3 and 4 show the second drive transistor 112 shown in Figure 1. In this context, the change in drain current when the drain voltage is changed, and the drive transistor shown in Figure 2. In the ZISTRA 211, the change in drain current when the drain voltage is changed was calculated. This figure shows the results. In Figures 3 and 4, the horizontal axis is drain voltage and the vertical axis is drain This is electric current. Note that the above calculation was performed using Silvaco's SMARTSPICE Ver3.16.1. 2. This calculation uses R, and the calculation model is the RPI model with LEVEL=36. Furthermore, the drive transistor 211, the first drive transistor 111, and the second drive transistor In each of the lampistors 112, the μ in the formula for calculating the current in the saturation region Vth and Cox are set based on the parameter conditions of the calculation software. The same value. Also, the drive transistor 211, the first drive transistor 111, and the second The channel width of each drive transistor 112 is set to 1 μm. Also, see Figures 3 and 4. Therefore, the drain voltage is in the range of -10V to 2V, and the potential of the data signal is -0.6V. A second drive transistor 211 and a second drive transistor with different values ​​in 0.2V increments within the range of up to 2V. This shows the drain current value for 112.

[0051] Figure 3(A) shows the drive transistor when the channel length of the drive transistor 211 is 46.9 μm. Figure 3(B) shows the drain current of the first drive transistor 1 The channel length of 11 is 30.9 μm, and the channel length of the second drive transistor 112 is Drain current of the second drive transistor 112 and drive transistor 21 when the diameter is 16 μm. The channel length of 1, the channel length (L1) of the first drive transistor 111 and the second drive The second drive transistor 11 when the sum of the channel lengths (L2) of the transistors 112 is equal. This is a diagram showing the drain current of transistor 2. Also, in the other parts, the drive transistor 211 The configuration is assumed to be the same as that of the first drive transistor 111. Also, see Figure 3(A) In the calculations explained using (B), the value of the first power supply potential VP1 is set to 2.1V, and the third The value of the power supply potential VP3 is set to 0.6V. Also, the second power supply potential VP2 in each calculation is The values ​​are the same. In this case, for example, in the uppermost curve of Figure 3(B), the drain voltage The saturation region is when the voltage is 0.1V or less.

[0052] As shown in Figures 3(A) and (B), the channel length of the drive transistor 211 and the first drive The sum of the channel length of the first drive transistor 111 and the channel length of the second drive transistor 112 is When equal, in the saturation region, the maximum value Id of the drain current of the drive transistor 211 211max The maximum value Id of the drain current of the second drive transistor 112 is greater than the value Id 112m ax This is because the first drive transistor 111 operates in the linear region, and the second drive The dynamic transistor 112 lowers the drain current value of the first drive transistor 111. Therefore, when the drain current of the second drive transistor 112 is reduced... Even in combination, channel length expansion is suppressed.

[0053] Furthermore, Figure 4(A) shows the third power supply potential VP compared to the calculation explained using Figure 3(B). The diagram shows the drain current of the second drive transistor 112 when only the value of 3 is changed. Yes. At this time, the value of the third power supply potential VP3 is set to 0.4V.

[0054] As shown in Figure 4(A), even when the third power supply potential is changed, the drive transistor Maximum drain current Id of TA211 211maxThe second drive transistor 112 Maximum drain current Id 112max That's lower.

[0055] Furthermore, Figure 4(B) shows the first drive transition in comparison with the calculation explained using Figure 3(B). The channel length of the second drive transistor 112 is made longer than the channel length of the star 111. This figure shows the drain current of the second drive transistor 112 when only the minute differs. In this case, the channel length of the first drive transistor 111 is set to 16 μm, and the second drive transistor The channel length of transistor 112 is set to 30.9 μm. Therefore, the channel of drive transistor 211 Channel length, channel length of the first drive transistor 111 and the second drive transistor 11 The sum of the channel lengths of the two is equal.

[0056] As shown in Figure 4(B), the second drive transistor has a channel length greater than that of the first drive transistor 111. The channel length of transistor 112 is increased, and the channel length of drive transistor 211 is also increased. The channel length of the first drive transistor 111 and the channel length of the second drive transistor 112 Even when the sum of the values ​​is equal, the maximum drain current of the drive transistor 211 shown in Figure 2 Value Id 211max The drain current of the second drive transistor 112 shown in Figure 1 is the maximum Large value ID 112max The value is lower. Therefore, the drain current of the second drive transistor 112 is lower. Even when the flow rate is reduced, the expansion of the channel length is suppressed.

[0057] From Figures 3 and 4, the drain current of the second drive transistor 112 in the saturation region is as follows: It can be seen that channel length expansion can be suppressed when the maximum value satisfies equation (3).

[0058] As explained using Figures 3 and 4, the first drive transistor 111 and the second drive transistor The transistor 112 controls the drain current of the second drive transistor 112 in the saturation region. The drain current of the second drive transistor 112 is set such that the maximum value of the current satisfies equation (3). By controlling this, even if the drain current of the second drive transistor 112 is reduced, The channel length of the first drive transistor 111 and the second drive transistor 112 is increased. It can be suppressed.

[0059] Next, an example of the structure of the display device of this embodiment will be described.

[0060] The display device in this embodiment includes a switch transistor 110 and a first drive transistor. Semiconductor elements such as 111, a capacitive element 130, and a second drive transistor 112 are provided. A first substrate (also called an active matrix substrate), a second substrate, and the first substrate It includes an electroluminescent element provided between the first and second substrates.

[0061] First, Figure 5 shows an example of the structure of the active matrix substrate in the display device of this embodiment. This will be explained using the following. Figures 5(A) and 5(B) show the structure of the active matrix substrate, respectively. These are schematic plan and cross-sectional drawings illustrating the fabrication example. Also, Figure 5(B) is shown in Figure 5(A). This is a schematic cross-sectional view of line segment AB. Note that Figure 5 includes components that differ from the actual dimensions. Also, for convenience, in Figure 5(B), one of the active matrix substrates shown in Figure 5(A) is shown. Parts have been omitted. Also, the double wavy line is an abbreviation symbol.

[0062] The active matrix substrate shown in Figure 5(A) consists of a substrate 510, an insulating layer 511, and a semiconductor Layers 513a and 513b, insulating layer 517, conductive layers 518a to 518d, insulating layer 5 It includes 19 and conductive layers 520a to 520d.

[0063] The insulating layer 511 is provided on one plane of the substrate 510.

[0064] The insulating layer 511 functions, for example, as an underlayer.

[0065] Each of the semiconductor layers 513a and 513b is provided on a portion of the insulating layer 511.

[0066] The semiconductor layer 513a has impurity regions 514a to 514d and impurity region 515. Furthermore, a switch transistor 110 is placed between the impurity region 514a and the impurity region 514b. A filament formation region 516a is provided, and between the impurity region 514b and the impurity region 514c, A channel formation region 516b of the switch transistor 110 is provided. Also, an impurity region 5 15 is located between the impurity region 514c and the impurity region 514d.

[0067] Furthermore, the semiconductor layer 513b has impurity regions 514e to 514g. The channel formation region of the first drive transistor 111 is between region 514e and impurity region 514f. A region 516c is provided, and a second drive transistor is placed between the impurity region 514f and the impurity region 514g. A channel-forming region 516d is provided in the inverter 112. The channel length of 6c is longer than the channel length of the channel-forming region 516d.

[0068] The impurity regions 514a to 514g and impurity region 515 are impurities that impart a P-type conductivity. This is a region where pure elements are added, and the impurity concentration in impurity region 515 is the same as in impurity region 514. The impurity concentration is higher than a to 514g. Note that the capacitance line CsL and the first power line PSL1 are When a potential different from the first power supply potential VP1 is applied as a capacitive potential without connection, the semiconductor By omitting the doping of impurity elements into layer 513a and eliminating the impurity region 515, a capacitive element is created. 130 can be formed. The semiconductor layer 513a forms the channel of the switch transistor 110. It functions as one of a pair of electrodes in the layer and the capacitive element 130. Layer 513b is the channel formation layer for the first drive transistor 111, and the second drive transistor It functions as a channel-forming layer for ZISTA 112.

[0069] The insulating layer 517 is provided on the semiconductor layers 513a and 513b. Gate insulating layer of switch transistor 110, gate insulating layer of first drive transistor 111 The layers consist of a gate insulating layer for the second drive transistor 112 and a dielectric layer for the capacitive element 130. It has the function of being functional.

[0070] Each of the conductive layers 518a to 518d is provided on a portion of the insulating layer 517.

[0071] The conductive layer 518a is superimposed on the channel-forming regions 516a and 516b via the insulating layer 517. The conductive layer 518a has the function of a gate of the switch transistor 110. do.

[0072] The conductive layer 518b is superimposed on the impurity region 515 via the insulating layer 517. It functions as the other of the pair of electrodes that the capacitive element 130 has.

[0073] The conductive layer 518c is superimposed on the channel-forming region 516c via the insulating layer 517. 518c functions as the gate of the first drive transistor 111.

[0074] The conductive layer 518d is superimposed on the channel-forming region 516d via the insulating layer 517. 518d functions as the gate of the second drive transistor 112.

[0075] The insulating layer 519 is provided on the insulating layer 517 via conductive layers 518a to 518d. The insulating layer 519 functions as a planarization layer.

[0076] Each of the conductive layers 520a to 520d is provided on a portion of the insulating layer 519.

[0077] The conductive layer 520a has an impurity region at the first opening that penetrates the insulating layers 517 and 519. It is adjacent to 514a.

[0078] The conductive layer 520b is in contact with the conductive layer 518b at a second opening that penetrates the insulating layer 519. Furthermore, the conductive layer 520b has a third opening that penetrates the insulating layers 517 and 519. It is adjacent to the impurity region 514e.

[0079] The conductive layer 520c has an impurity region at the fourth opening that penetrates the insulating layers 517 and 519. It is in contact with 514d. Also, the conductive layer 520c is in contact with the fifth opening that penetrates the insulating layer 519. It then comes into contact with the conductive layer 518c.

[0080] The conductive layer 520d has an impurity region at the sixth opening that penetrates the insulating layers 517 and 519. It comes into contact with 514g.

[0081] Furthermore, an example of the structure of the display device of this embodiment will be explained with reference to Figure 6. This is a schematic cross-sectional diagram showing an example of the structure of a display device in the application form. Note that the EL element 120 is above The structure is not limited to one that emits light in the planar direction; a structure that emits light in the downward direction is also acceptable.

[0082] The display device shown in Figure 6 includes, in addition to the active matrix substrate shown in Figure 5, an insulating layer 521, A conductive layer 522, an insulating layer 523, a light-emitting layer 524, a conductive layer 525, a substrate 530, and It includes a color layer 531, an insulating layer 532, and an insulating layer 540.

[0083] The insulating layer 521 is provided on top of the insulating layer 519 and the conductive layers 520a to 520d.

[0084] The conductive layer 522 is provided on top of the insulating layer 521. The conductive layer 522 is in contact with the conductive layer 520d at the seventh opening that penetrates the EL element 1. 20 has the function of an anode. Also, in the display device shown in Figure 6, conductive layer 5 22, capacitance is formed by the insulating layer 521 and the conductive layers 520a to 520d respectively. This is also a good approach. This allows, for example, the suppression of fluctuations in the first power supply potential VP1.

[0085] The insulating layer 523 is provided on top of the conductive layer 522.

[0086] The light-emitting layer 524 is in contact with the conductive layer 522 at an eighth opening provided in the insulating layer 523. The light-emitting layer 524 functions as the light-emitting layer of the EL element 120.

[0087] The conductive layer 525 is provided in contact with the light-emitting layer 524. The conductive layer 525 is located on the EL element 12 It possesses the function of a cathode, as 0 does.

[0088] The colored layer 531 is provided on one plane of the substrate 530. The colored layer 531 is from the light-emitting layer 524. It functions as a color filter that transmits light of a specific wavelength.

[0089] The insulating layer 532 is provided on one plane of the substrate 530 via the colored layer 531.

[0090] The insulating layer 540 is provided between the insulating layer 532 and the conductive layer 525.

[0091] Furthermore, each component is explained below.

[0092] Substrates 510 and 530 can be, for example, a glass substrate, a silicon substrate, or plastic. A substrate can be used.

[0093] As the insulating layer 511, for example, a layer containing an oxide insulating material can be used, for example, an oxide A layer containing materials such as silicon oxide, silicon nitride, or silicon nitride can be used. It is possible. Furthermore, the insulating layer 511 can be constructed by laminating layers of a material applicable to the insulating layer 511. It can also be done this way.

[0094] For example, single-crystal semiconductor layers can be used as semiconductor layers 513a and 513b. For example, a single-crystal silicon layer can be used.

[0095] Here, examples of the formation of semiconductor layers 513a and 513b are described below.

[0096] For example, prepare a first semiconductor substrate and a second semiconductor substrate with an insulating layer formed on its upper surface. Oh, an impurity element that imparts an N-type or P-type conductivity to the first semiconductor substrate is added in advance. Alternatively, an oxide insulating layer or a nitride insulating layer may be formed on the first semiconductor substrate beforehand. stomach.

[0097] For example, an oxide insulating film is formed by thermal oxidation, CVD, or sputtering. By doing so, an insulating layer can be formed on the second semiconductor substrate.

[0098] Furthermore, an ion beam consisting of ions accelerated by an electric field is injected into the second semiconductor substrate, A brittle region is formed in a region at a certain depth from the surface of the semiconductor substrate. By adjusting the energy, ion mass and charge, ion incidence angle, etc., the above embrittlement region Adjust the depth of the area.

[0099] For example, ions are injected into the semiconductor substrate using an ion doping device or an ion implantation device. It is possible to enter.

[0100] Furthermore, as the ions to be irradiated, one or more of hydrogen or helium can be used. Yes, it is possible. For example, when irradiating with hydrogen ions using an ion doping device, the irradiated ions On, H3 + By increasing the ratio, the efficiency of ion irradiation can be improved. It is possible. Specifically, H + H2 + H3 + H3 + The percentage is 50% or more ( Preferably, the percentage should be 80% or more.

[0101] Furthermore, the first semiconductor substrate and the second semiconductor are connected via an insulating layer provided on the second semiconductor substrate. The substrates are bonded together. Note that if an insulating layer is also provided on the first semiconductor substrate, the second semiconductor The first semiconductor is connected via an insulating layer provided on the substrate and an insulating layer provided on the first semiconductor substrate. The first semiconductor substrate and the second semiconductor substrate are bonded together. The insulating layer provided between the conductive substrates becomes the insulating layer 511.

[0102] Furthermore, heat treatment is performed to separate the second semiconductor substrate using the embrittlement region as a cleavage plane. Therefore, a semiconductor layer can be formed on the insulating layer 511. Note that the surface of the above semiconductor layer By irradiating it with laser light, the flatness of the surface of the semiconductor layer can be improved. Furthermore, by etching a portion of the semiconductor layer, semiconductor layers 513a and 513b It can form.

[0103] However, this is not limited to the above, and for example, semiconductors using methods such as the smartcut method or the SIMOX method. Layers 513a and 513b can also be formed. In addition, insulating isolation regions can be formed on a single-crystal semiconductor substrate. Even if the semiconductor region formed by creating the region is used as semiconductor layers 513a and 513b good.

[0104] The impurity regions 514a to 514g and impurity region 515 are, for example, semiconductor layer 513a and It is formed by adding impurity elements that impart a conductivity type to 513b. For example, N-channel type In the case of transistors, impurity elements (such as phosphorus) that impart the N-type conductivity are added. In the case of a P-channel transistor, an impurity element (for example, boron) imparts the P-type conductivity. Add (do).

[0105] Examples of insulating layer 517 include silicon oxide, silicon nitride, silicon oxynitride, and silicon nitride. Silicon oxide, aluminum oxide, aluminum nitride, aluminum oxide nitride, aluminum oxide nitride A layer containing materials such as luminium or hafnium oxide can be used. The insulating layer 517 can also be constructed by laminating layers applicable to layer 517.

[0106] Examples of conductive layers 518a to 518d include molybdenum, titanium, chromium, tantalum, Magnesium, silver, tungsten, aluminum, copper, neodymium, or scandium A layer of material containing metal materials such as can be used. Also, conductive layers 518a to 518 As for d, a layer containing a conductive metal oxide can also be used. For example, indium oxide (In2O3), tin oxide (SnO2), zinc oxide (Zn O), Indium tin oxide (In2O3-SnO2, sometimes abbreviated as ITO) , metal oxides such as indium zinc oxide (In2O3-ZnO), or silicon, acid Silicon oxide and a metal oxide containing nitrogen can be used. Also, conductive layers 518a to By laminating layers of material applicable to 518d, conductive layers 518a to 518d are formed. It can also be done this way.

[0107] Examples of insulating layer 519 include silicon oxide, silicon nitride, silicon oxynitride, and silicon nitride. Silicon oxide, aluminum oxide, aluminum nitride, aluminum oxide nitride, aluminum oxide nitride A layer containing materials such as luminium or hafnium oxide can be used. The insulating layer 519 can also be constructed by laminating layers applicable to layer 519.

[0108] Examples of conductive layers 520a to 520d include molybdenum, titanium, chromium, tantalum, Magnesium, silver, tungsten, aluminum, copper, neodymium, ruthenium, or scallop A layer of material containing metallic materials such as dium can be used. Also, conductive layer 520a For layer 520d, a layer containing a conductive metal oxide can also be used. Examples of oxides include indium oxide (In2O3), tin oxide (SnO2), and phosphate oxide. Lead (ZnO), indium tin oxide (In2O3-SnO2, abbreviated as ITO) (There are), metal oxides such as indium-zinc oxide (In2O3-ZnO), or silica A metal oxide containing condensate, silicon oxide, and nitrogen can be used. Also, a conductive layer 52 The conductive layers 520a to 520d are constructed by laminating layers of material applicable to 0a to 520d. It is possible to achieve this.

[0109] For example, an organic insulating layer or an inorganic insulating layer can be used as the insulating layer 521.

[0110] Examples of conductive layer 522 include molybdenum, titanium, chromium, tantalum, magnesium, Silver, tungsten, aluminum, copper, neodymium, ruthenium, or scandium, etc. A layer of material containing a metallic material can be used. Furthermore, materials applicable to the conductive layer 522... The conductive layer 522 can also be formed by stacking layers.

[0111] For example, an organic insulating layer or an inorganic insulating layer can be used as the insulating layer 523.

[0112] The light-emitting layer 524 may be, for example, a light-emitting layer using a light-emitting material that emits light of a specific color. This can be used. Furthermore, a lamination of light-emitting layers that emit light exhibiting different color characteristics can be used. The light-emitting layer 524 may be constructed using the following: the light-emitting material may be a fluorescent material or a phosphorescent material. The electroluminescent material can be used. In addition, multiple electroluminescent materials can be used. A light-emitting material may be constructed using a material containing a luminescent material. For example, a material that emits blue light. A layer of fluorescent material, a layer of first phosphorescent material that emits orange light, and a layer of orange light By stacking layers of a second phosphorescent material that emits light, a light-emitting layer that emits white light is formed. Also, as an electroluminescent material, organic electroluminescent material Alternatively, an inorganic electroluminescent material can be used. In addition to the above-mentioned light-emitting layer, For example, one or more of the hole injection layer, hole transport layer, electron injection layer, and electron transport layer are provided. A field-emitting layer may be constructed.

[0113] As the conductive layer 525, for example, a layer of a light-transmitting metal oxide can be used. Examples of metal oxides include indium oxide (In2O3), tin oxide (SnO2), and acid Zinc oxide (ZnO), indium tin oxide (In2O3-SnO2, abbreviated as ITO) In some cases, metal oxides such as indium zinc oxide (In2O3-ZnO), or Silicon, silicon oxide, and the metal oxide containing nitrogen can be used. The conductive layer 525 can also be constructed by laminating layers of materials applicable to 525.

[0114] The colored layer 531 can be, for example, light of a wavelength that produces red light, light of a wavelength that produces green light, or blue light. A layer that transmits light of a wavelength exhibiting this characteristic and contains dyes or pigments can be used. As 531, a dye or pigment that transmits light exhibiting the color cyan, magenta, or yellow. A layer containing a dye may also be used. For example, if a dye is included, the colored layer 531 may be, for example, photolithography. If formed using a graphic, printing, or inkjet method and containing pigment, the colored layer 531 is formed using photolithography, printing, electrodeposition, or electrophotography. For example, by using the inkjet method, it is possible to manufacture at room temperature, manufacture at a low vacuum, or It can be manufactured on large substrates. Furthermore, it can be manufactured without using a resist mask. This allows for a reduction in manufacturing costs and the number of manufacturing steps.

[0115] For example, the insulating layer 532 can be a layer of a material applicable to the insulating layer 517. Alternatively, the insulating layer 532 may be constructed by laminating layers of a material applicable to the insulating layer 532. Note that the insulating layer 532 does not necessarily have to be provided, but by providing the insulating layer 532 This makes it possible to suppress the intrusion of impurities from the colored layer 531 into the EL element 120.

[0116] For example, a layer of resin material can be used as the insulating layer 540. The insulating layer 540 may be constructed by laminating layers of applicable materials.

[0117] As shown in Figures 5 and 6, in the display device of this embodiment, a specific color is used as the EL element 120. An EL element 120 that emits monochromatic light exhibiting the following light, and of the light emitted by the EL element 120, The structure includes a colored layer that transmits light of a specific wavelength. By using the above structure, A full-color image can be created without forming multiple EL elements 120 that emit light of different colors from each other. Because it can display this information, the manufacturing process can be simplified and the yield can be improved. For example, since the EL element 120 can be fabricated without using a metal mask, The manufacturing process becomes easier. Also, image contrast can be improved. Furthermore, EL This improves the quality of element 120 and enhances the reliability of EL element 120.

[0118] Furthermore, in the display device of this embodiment, the structure of the EL element 120 is such that a transistor is used. By creating a structure in which light is extracted through a substrate that does not have an element, the element The area above the designated region can also be used as a light-emitting region, thereby improving the aperture ratio. ru.

[0119] Furthermore, an example of the configuration of the display device of this embodiment will be explained with reference to Figure 7. This is a block diagram showing an example configuration of a display device.

[0120] The display device shown in Figure 7 has multiple pixels arranged in an X row and Y column (where X and Y are natural numbers greater than or equal to 2). The track 910, the first data signal line DL_1 to the Y data signal line DL_Y, and the first G The gate signal lines GL_1 to the Xth gate signal lines GL_X, the first power line PSL1, and the second It includes a third power line PSL2 and a third power line PSL3.

[0121] For each of the multiple pixel circuits 910, for example, the circuit configuration shown in Figure 1 can be applied. Yes, it's possible. For example, three types of pixels for red (R) display, green (G) display, and blue (B) display. A single pixel can be formed by path 910. The horizontal resolution of the display device in this embodiment is 8 It is preferable that the pixel density is 00 ppi or higher, for example, 800 ppi or more and 1000 ppi or less. It is preferable to do so.

[0122] At this time, in each of the multiple pixel circuits 910, the switch transistor 110 is The source and drain of the data signal line are the first data signal line DL_1 to the Y data signal line. It is connected to one of the DL_Y. Also, the gate of the switch transistor 110 is It is connected to one of the gate signal lines GL_1 through X, from gate signal line GL_X.

[0123] Furthermore, one of the source and drain of the first drive transistor 111 is connected to the first power supply. It is connected to line PSL1.

[0124] Furthermore, the other electrode of the pair of electrodes of the capacitive element 130 is connected to the first power line via the capacitance line CsL. Connects to PSL1.

[0125] Furthermore, one of the anode and cathode of the EL element 120 is connected to the second power line PSL2. Connected.

[0126] Furthermore, the gate of the second drive transistor 112 is connected to the third power line PSL3. It can be done.

[0127] The potential of the first data signal line DL_1 to the Y data signal line DL_Y is determined by the drive circuit 901 It is controlled by, for example, an analog switch, a latching circuit, and an operator. It can be constructed using an amplifier.

[0128] The potential of the first gate signal line GL_1 to the Xth gate signal line GL_X is determined by the drive circuit 902 It is controlled by the following. The drive circuit 902 is controlled by the same process as the pixel circuit 910, and the pixel cycle The circuit 902 may be formed on the same substrate as the path 910. The drive circuit 902 may use, for example, a shift register. It can be constructed using this method.

[0129] Furthermore, the first power potential VP1 is supplied to the first power line PSL1, and the second power line PSL2 The second power potential VP2 is supplied to the third power line PSL3, and the third power supply is supplied to the third power line PSL3. The potential VP3 can be generated by the power supply circuit 903. Furthermore, the power supply circuit 903 drives the drive circuit 90 Power supply voltage is supplied to 1 and the drive circuit 902. Note that the power supply circuit 903 supplies power to the pixel circuit 910 It may also be formed on a separate circuit board and connected by wiring or the like.

[0130] Each of the multiple pixel circuits 910 is electrically connected to a common third power line PSL3. This eliminates the need for separate drive circuits, allowing for a simpler circuit configuration.

[0131] As explained with reference to Figure 7, in the display device of this embodiment, multiple pixel circuits 910 are shared By electrically connecting to the third power line, a common third power potential is supplied. Therefore, in each pixel circuit 910, without using a separate drive circuit, the second drive transistor The current value supplied to the EL element 120 can be controlled by 112.

[0132] (Embodiment 2) In this embodiment, the housing is equipped with a panel configured using the display device of Embodiment 1 described above. An example of a sub-device will be explained using Figure 8.

[0133] The electronic device shown in Figure 8(A) is an example of a portable information terminal.

[0134] The electronic device shown in Figure 8(A) consists of a housing 1011 and a panel 101 provided on the housing 1011. It is equipped with 2, a button 1013, and a speaker 1014.

[0135] Furthermore, the housing 1011 has connection terminals for connecting external devices, such as the electronic equipment shown in Figure 8(A). One or more of the buttons shown in Figure 8(A) for operating the electronic device may be provided.

[0136] Panel 1012 has the functions of a display panel and a touch panel. For example, a panel is used which is constructed by layering a touch panel on the display device shown in Embodiment 1. It is possible.

[0137] Button 1013 is provided on the housing 1011. For example, Button 101 3 is provided so that pressing Button 1013 can control whether the electronic device is turned on or not.

[0138] Speaker 1014 is provided on the housing 1011. Speaker 1014 has a function of outputting sound.

[0139] In addition, a microphone may be provided on the housing 1011. By providing a microphone, for example, the electronic device shown in FIG. 8 ( A) can function as a telephone.

[0140] The electronic device shown in FIG. 8 (A) has a function as one or more of, for example, a telephone, an e-book, a personal computer, and a gaming machine.

[0141] The electronic device shown in FIG. 8 (B) is an example of a foldable information terminal.

[0142] The electronic device shown in FIG. 8 (B) includes a housing 1021a, a housing 1021b, a panel 1022a provided on the housing 1021a, a panel 1 022b provided on the housing 1021b, a shaft portion 1023, a button 1024, a connection terminal 1025, a recording medium insertion portion 1026, and a speaker 1027.

[0143] The housing 1021a and the housing 1021b are connected by a shaft portion 1023. <000090​​​​​​​​​​​​ In the electronic device shown in FIG. 8(B), since there is a shaft portion 1023, for example, by moving the housing 1021a or the housing 1021b and superimposing the housing 1021a on the housing 1021b, the electronic device can be folded.

[0146] The button 1024 is provided on the housing 1021b. Note that the button 102 4 may be provided on the housing 1021a. For example, by providing a button 1024 having a function as a power button, it is possible to control whether to supply power to the circuit in the electronic device by pressing the button 1024.

[0147] The connection terminal 1025 is provided on the housing 1021a. Note that the connection terminal 1 025 may be provided on the housing 1021b. Also, a plurality of connection terminals 1025 may be provided on one or both of the housing 1021a and the housing 102 1b. The connection terminal 1025 is a terminal for connecting the electronic device shown in FIG. 8(B) to other devices.

[0148] The recording medium insertion portion 1026 is provided on the housing 1021a. Note that the recording medium insertion portion 1026 may be provided on the housing 1021b. Also, a plurality of recording medium insertion portions 1026 may be provided on one or both of the housing 102 1a and the housing 1021b. For example, by inserting a card-type recording medium into the recording medium insertion portion, data can be read from the card-type recording medium into the electronic device, or data in the electronic device can be written to the card-type recording medium.

[0149] The speaker 1027 is provided on the housing 1021b. The speaker 1027 has a function of outputting sound. Note that the speaker 1027 may be provided on the housing 102 1a instead of the housing 1021b. ​​

[0150] A microphone may be provided in either housing 1021a or housing 1021b. This allows, for example, the electronic device shown in Figure 8(B) to function as a telephone.

[0151] The electronic devices shown in Figure 8(B) include, for example, telephones, e-readers, personal computers, and It functions as one or more gaming machines.

[0152] The electronic device shown in Figure 8(C) is an example of a stationary information terminal. The terminal consists of a housing 1031, a panel 1032 provided on the housing 1031, and a button 1033 It is equipped with a speaker 1034.

[0153] Panel 1032 has the functions of a display panel and a touch panel. For example, a panel configured by stacking the display device and touch panel of Embodiment 1 can be applied. .

[0154] The panel 1032 can also be installed on the deck portion 1035 of the housing 1031.

[0155] Furthermore, the housing 1031 includes a ticket output unit for outputting tickets, a coin slot, and one of the banknote insertion units. Alternatively, multiple options may be provided.

[0156] Button 1033 is provided on the housing 1031. For example, it has the function of a power button. By providing a button 1033, pressing the button 1033 activates the circuitry within the electronic device. It can control whether or not power is supplied.

[0157] The speaker 1034 is located in the enclosure 1031. The speaker 1034 outputs sound. It has the function of doing so.

[0158] The electronic device shown in FIG. 8(C) is, for example, an automated teller machine, an information communication terminal (also referred to as a multimedia station) for placing orders such as tickets, or has a function as a gaming machine. has.

[0159] FIG. 8(D) is an example of an installed information terminal. The electronic device shown in FIG. 8(D) includes a housing 1041, a panel 1042 provided on the housing 1041, a support base 1043 that supports the housing 1041, buttons 1044, connection terminals 1045, and speakers 1046. 3, buttons 1044, connection terminals 1045, and speakers 1046.

[0160] Note that one or more connection terminals for connecting to an external device to the housing 1041 and one or more buttons for operating the electronic device shown in FIG. 8(D) may be provided. The electronic device shown in FIG. 8(C) is, for example, an automated teller machine, an information communication terminal (also referred to as a multimedia station) for placing orders such as tickets, or has a function as a gaming machine.

[0161] The panel 1042 has a function as a display panel. As the panel 1042, the display device of Embodiment 1 can be applied. Further, a touch panel may be overlaid on the display device of Embodiment 1 to add a function as a touch panel to the panel 1042.

[0162] The buttons 1044 are provided on the housing 1041. For example, by providing a button 1044 having a function as a power button, it is possible to control whether to supply power to the circuit in the electronic device by pressing the button 1044.

[0163] The connection terminals 1045 are provided on the housing 1041. The connection terminals 1045 are terminals for connecting the electronic device shown in FIG. 8(D) to other devices. For example, by connecting the electronic device shown in FIG. 8(D) and a personal computer through the connection terminals 1045, The system can display an image on panel 1042 corresponding to the data signal input from the computer. Yes, it is possible. For example, the panel 1042 of the electronic device shown in Figure 8(D) is connected to the panel of the electronic device. If it's larger than the 360 Yes.

[0164] The speaker 1046 is provided in the enclosure 1041. The speaker 1046 outputs sound. It has the function of doing so.

[0165] The electronic devices shown in Figure 8(D) include, for example, an output monitor, a personal computer, or a television. It functions as a John device.

[0166] As explained with reference to Figure 8, by using the display device of Embodiment 1 as a panel, the electronic device The panel on the container can be made with high resolution. [Explanation of symbols]

[0167] 110 Switch Transistors 111 First drive transistor 112 Second drive transistor 120 EL elements 130 Capacitive elements 211 drive transistors 510 circuit board 511 Insulating layer 513a Semiconductor layer 513b Semiconductor layer 514a Impurity region 514b Impurity region 514c Impurity region 514d Impurity region 514e Impurity region 514f Impurity region 514g impurity area 515 Impurity region 516a Channel formation region 516b Channel formation region 516c Channel formation region 516d Channel formation region 517 Insulating layer 518a conductive layer 518b Conductive layer 518c conductive layer 518d conductive layer 519 Insulating layer 520a conductive layer 520b conductive layer 520c conductive layer 520d conductive layer 521 Insulating layer 522 Conductive layer 523 Insulating layer 524 Emitting layer 525 Conductive layer 530 circuit boards 531 Colored layer 532 Insulating layer 540 Insulating layer 901 Drive Circuit 902 Drive Circuit 903 Power supply circuit 910 pixel circuit 1011 cabinet 1012 Panel 1013 Button 1014 Speaker 1021a Enclosure 1021b enclosure 1022a Panel 1022b Panel 1023 Shaft 1024 buttons 1025 Connection terminal 1026 Recording medium insertion section 1027 Speakers 1031 Casing 1032 Panel 1033 buttons 1034 Speakers 1035 Deck section 1041 cabinet 1042 Panel 1043 Support stand 1044 buttons 1045 Connection terminal 1046 Speakers

Claims

[Claim 1] Having a first insulating layer on the substrate, The semiconductor layer is located on the first insulating layer, The semiconductor layer has a gate insulating layer, Having a gate electrode on the gate insulating layer, The gate electrode is a transistor that crosses the semiconductor layer twice.

Images