JP2009169070A - Color image display device, shadow mask, and method of manufacturing color image display device using shadow mask - Google Patents

Abstract

In a full-color display device, a high aperture ratio of a pixel can be realized by using a high-intensity shadow mask.
When focusing on the same colors of R, G, and B, the pixel array section is arranged by shifting the subpixel position in the horizontal direction for each row, so that when viewed by color, any color has a stripe structure. The sub-pixel positions of the same color are arranged in an oblique direction without adopting. The corresponding shadow mask 620A is arranged so that the openings 622 are arranged in a line in an oblique direction. Since the interval portion 624 that bridges in an oblique direction is provided for each pixel, the strength of the mask can be increased and a high-strength mask that can improve the deflection can be obtained. A decrease in the aperture ratio due to vapor deposition for forming the light emitting layer can be suppressed, and a high aperture ratio can be achieved with high strength in a high-definition panel.
[Selection] Figure 6A

Description

  The present invention relates to a color image display device having a pixel array section in which pixel circuits (also referred to as pixels) having electro-optical elements (also referred to as display elements and light-emitting elements) are arranged in a matrix, and a method for manufacturing the same. And a shadow mask used in the manufacturing method.

  As a display element of a pixel, there is a display device using an electro-optical element whose luminance changes depending on an applied voltage or a flowing current. For example, a liquid crystal display element is a typical example of an electro-optical element whose luminance changes depending on an applied voltage, and an organic electroluminescence (Organic Electro Luminescence, Organic EL, Organic) (Light Emitting Diode, OLED; hereinafter referred to as “organic EL”) A typical example is an element. The organic EL display device using the latter organic EL element is a so-called self-luminous display device using an electro-optic element which is a self-luminous element as a pixel display element.

  An organic EL element is an electro-optical element utilizing a phenomenon that light is emitted when an electric field is applied to an organic thin film. Since the organic EL element can be driven with a relatively low applied voltage (for example, 10 V or less), the power consumption is low. Further, since the organic EL element is a self-luminous element that emits light by itself, an auxiliary illumination member such as a backlight that is required in a liquid crystal display device is not required, and the weight and thickness can be easily reduced. Furthermore, since the response speed of the organic EL element is very high (for example, about several μs), an afterimage at the time of displaying a moving image does not occur. Because of these advantages, development of a flat self-luminous display device using an organic EL element as an electro-optical element has become active recently (see, for example, Patent Documents 1 to 6).

JP-A-2005-197202 Japanese Patent Laid-Open No. 05-299177 JP 2006-113376 A JP 2005-155853 A JP 2003-316291 A JP 2005-345766 A

  By the way, in a display device using a current-driven electro-optic element, typically an organic EL element, for example, three primary colors (sub-pixels) are formed on each electro-optic element (subpixel) that emits white light. R, G, and B) color separation filters are formed to form a single pixel for color display and a combination of electro-optic elements (sub-pixels) that emit light in each of the three primary colors (R, G, and B). It can be roughly divided into methods for forming one pixel for color display.

  In the case of the latter method, it is necessary to form the light emitting layer for each color by separately coloring pigments (for example, three primary colors of R, G, and B) within a narrow range. In order to separate the colors, generally, a thin metal plate (shadow mask) provided with openings is placed in front of the substrate, and dyes are vapor-deposited in order only on the openings, and light emitting layers for each color. The shadow mask method for forming the film is employed.

  Although details will be described in the embodiment, as a mask used in the shadow mask method, all the vertical sub-pixels of a certain color are collectively provided with slit-like openings, and the openings are provided at a pixel pitch in the horizontal direction. A mask (hereinafter also referred to as a slit mask) or a mask (hereinafter referred to as a vertical stripe) in which an opening is provided for each vertical subpixel of a certain color and arranged in a vertical stripe shape, and the openings are provided at a pixel pitch in the horizontal direction. Each pixel is also referred to as a mask).

  However, the slit mask is liable to be loosened, which makes it difficult to achieve horizontal alignment accuracy. As a countermeasure for this problem, if the aperture is designed to be small in consideration of mask misalignment, the pixel aperture ratio decreases.

  On the other hand, in order to achieve a high aperture ratio with high definition, a mask for each vertical stripe pixel is desirable. In this mask, intervals are provided between the openings provided for each vertical sub-pixel, so that the intervals form a bridge in the horizontal direction, and the mask strength is significantly increased compared to the slit mask. On the other hand, there is a difficulty that the interval portion lowers the pixel aperture ratio.

  The present invention has been made in view of the above circumstances, and a manufacturing method using a high-strength mask is employed when a shadow mask method is employed to form a light emitting layer for each color to achieve full color display devices. Another object is to provide a mechanism that can improve the pixel aperture ratio of a display device.

  In one embodiment of the color image display device according to the present invention, the position of one electro-optical element of the same color is sequentially shifted in the horizontal direction of the pixel array portion, and the position of the electro-optical element of the same color is oblique. Are arranged in a row. In other words, when focusing on color pixels by color, the sub-pixel positions of the color are arranged in a row diagonally from the upper left to the lower right direction or from the upper right to the lower left direction, and no color adopts a stripe structure. Characterized by points.

  A corresponding shadow mask for separately coating the light emitting layer of the color image display device by color is provided with an opening having a shape and a size corresponding to the light emitting layer of the electro-optic element for a certain color. Are arranged in a line so as to correspond to the diagonal direction of the pixel array portion. In terms of a mask in which an opening corresponding to one subpixel is provided for each pixel, one opening is similar to a mask for each vertical stripe pixel corresponding to the size of the opening of one electro-optic element. However, it differs in that each opening is arranged so as to correspond to the diagonal direction of the pixel array portion.

  When such a shadow mask is used to separately coat the light emitting layer of the electro-optical element by color, each of the openings of the shadow mask is positioned at the position of the light emitting layer of the electro-optical element of a desired color of one pixel for color display. In the film-forming step for forming a light-emitting layer of the desired color, the horizontal direction of the pixel array unit is changed every time the desired color is switched. In addition, the position of the opening of the shadow mask is shifted by the arrangement pitch of the electro-optic elements.

  By arranging the subpixel positions (positions of the light emitting layer of the electro-optic element) in the pixel array section in an oblique line, the distance between the pixels in the vertical direction can be narrowed to the limit. In addition, the shadow mask has an interval between the openings arranged in an oblique direction, so that a sufficiently large distance between the openings in the vertical direction and the horizontal direction can be secured, and the interval parts arranged in the oblique direction are provided. It can function to bridge the mask.

  Here, the vertical direction of the pixel array portion and the horizontal direction orthogonal to the vertical direction are relative to each other, and the direction in which the scanning speed is low is generally referred to as the column direction or the vertical direction. The high-speed direction is called the row direction or horizontal direction. However, for example, if the drawing is rotated by 90 degrees, the relationship between the top, bottom, left and right changes, and the relationship between rows and columns or vertical and horizontal is reversed, which is not absolute. Hereinafter, the column direction of the pixel array portion is assumed to be a vertical direction, and the row direction of the pixel array portion is representatively described as being a horizontal direction.

  According to an embodiment of the color image display device of the present invention, the distance between pixels in the vertical direction can be reduced to the limit in the pixel array section, and the pixel aperture ratio can be increased accordingly. According to one aspect of the shadow mask of the present invention, the interval between the openings can be made to function as a bridge in an oblique direction, so that the mask strength is higher than that of the slit mask. be able to. Both the mask strength and the pixel aperture ratio can be satisfied, and a high aperture ratio of the pixel can be realized by using a high-intensity shadow mask.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Overview of display device>
1 and 1A are block diagrams showing an outline of the configuration of an active matrix display device which is an embodiment of a display device according to the present invention. FIG. 1 is a block diagram showing an outline of a configuration of a general active matrix display device, and FIG. 1A is a block diagram showing an outline of a color image display compatible one.

  In the configuration example shown here, for example, an organic EL element is used as a display element (electro-optic element, light-emitting element) of a pixel, and a polysilicon thin film transistor (TFT) is used as an active element. A case where the present invention is applied to an active matrix type organic EL display (hereinafter referred to as “organic EL display device”) formed by forming organic EL elements on the substrate will be described as an example.

  In the following description of the overall configuration, an organic EL element is specifically described as an example of a pixel display element. However, this is merely an example, and the target display element is not limited to an organic EL element. In general, all embodiments described later can be applied to all display elements that emit light by current drive.

  As shown in FIG. 1, the display device 1 has an aspect ratio in which a pixel circuit (also referred to as a pixel) P having organic EL elements (not shown) as a plurality of display elements has a display aspect ratio of X: Display panel unit 100 arranged so as to constitute an effective video area of Y (for example, 9:16), and a drive signal generation as an example of a panel control unit that emits various pulse signals for driving and controlling the display panel unit 100 Section (so-called timing generator) 200 and video signal processing section 220. The drive signal generation unit 200 and the video signal processing unit 220 are built in a one-chip IC (Integrated Circuit), and are arranged outside the display panel unit 100 in this example.

  As shown in the figure, the product form is provided as a display device 1 in the form of a module (composite part) including all of the display panel unit 100, the drive signal generation unit 200, and the video signal processing unit 220. For example, the display device 1 can be provided only by the display panel unit 100.

  The display device 1 also includes a module-shaped one with a sealed configuration. For example, a display module formed by being attached to a facing portion such as transparent glass on the pixel array portion 102 is applicable. The transparent counter part may be provided with a color filter, a protective film, a light shielding film, and the like. The display module may be provided with a circuit unit for inputting / outputting a video signal Vsig and various drive pulses to / from the pixel array unit 102 from the outside, an FPC (flexible printed circuit), and the like.

  In addition, such a display device 1 includes various electronic devices such as a portable music player, a digital camera, a notebook personal computer, a cellular phone using a recording medium such as a semiconductor memory, a mini disk (MD), and a cassette tape. Video signals input to electronic devices such as mobile terminal devices such as video cameras, and video signals generated in electronic devices are used as display parts for electronic devices in various fields that display them as still images or moving images (videos). it can.

  The display panel unit 100 includes a pixel array unit 102 in which pixel circuits P are arranged in a matrix of n rows × m columns on a substrate 101, a vertical drive unit 103 that scans the pixel circuits P in the vertical direction, and pixels A horizontal drive unit (also referred to as a horizontal selector or a data line drive unit) 106 that scans the circuit P in the horizontal direction, an interface (IF) unit 130 that interfaces each of the drive units 103 and 106 with an external circuit, Connection terminal portions (pad portions) 108 and the like are integrated. That is, peripheral drive circuits such as the vertical drive unit 103, the horizontal drive unit 106, and the interface unit 130 are formed on the same substrate 101 as the pixel array unit 102.

  The interface unit 130 includes a vertical IF unit 133 that interfaces with the vertical drive unit 103 and an external circuit, and a horizontal IF unit 136 that interfaces with the horizontal drive unit 106 and an external circuit.

  The vertical driving unit 103 (the writing scanning unit 104 and the driving scanning unit 105) and the horizontal driving unit 106 control writing of the signal potential to the holding capacitor, threshold correction operation, mobility correction operation, and bootstrap operation. A control unit 109 is configured. A drive circuit that drives the pixel circuit P of the pixel array unit 102 includes the control unit 109 and the interface unit 130 (vertical IF unit 133 and horizontal IF unit 136).

  The vertical drive unit 103 includes, for example, a write scan unit (write scanner WS; Write Scan) 104 and a drive scan unit (drive scanner DS; Drive Scan) 105 that functions as a power supply scanner having power supply capability. For example, the pixel array unit 102 is driven by the writing scanning unit 104 and the driving scanning unit 105 from one side or both sides in the horizontal direction shown in the figure, and driven by the horizontal driving unit 106 from one side or both sides in the vertical direction shown in the figure. It has come to be.

  Various pulse signals are supplied to the terminal unit 108 from the drive signal generation unit 200 arranged outside the display device 1. Similarly, the video signal Vsig is supplied from the video signal processing unit 220. In the case of color display compatibility, video signals Vsig_R, G, and B for each color (in this example, three primary colors of R (red), G (green), and B (blue)) are supplied.

  For example, as a pulse signal for vertical driving, shift start pulses SPDS and SPWS which are examples of vertical write start pulses and vertical scanning clocks CKDS and CKWS (vertical scanning clocks xCKDS and xCKWS whose phases are reversed as necessary) ) And other necessary pulse signals are supplied. In addition, as a pulse signal for horizontal driving, necessary pulse signals such as a horizontal start pulse SPH, which is an example of a horizontal write start pulse, and a horizontal scanning clock CKH (and a horizontal scanning clock xCKH whose phase is inverted as necessary) are supplied. Is done.

  Each terminal of the terminal unit 108 is connected to the vertical driving unit 103 and the horizontal driving unit 106 via a wiring 109. For example, each pulse supplied to the terminal unit 108 is internally adjusted to a voltage level by a level shifter unit (not shown) as necessary, and then supplied to each unit of the vertical driving unit 103 and the horizontal driving unit 106 via a buffer. Supplied.

  Although the pixel array unit 102 is not shown in the drawing (details will be described later), pixel circuits P in which pixel transistors are provided with respect to an organic EL element as a display element are two-dimensionally arranged in a matrix form. On the other hand, scanning lines are wired for each row, and signal lines are wired for each column.

  For example, in the pixel array portion 102, a scanning line (gate line) 104WS and a video signal line (data line) 106HS are formed. An organic EL element (not shown) and a thin film transistor for driving the organic EL element are formed at the intersection of the two. A pixel circuit P is configured by a combination of an organic EL element and a thin film transistor.

  Specifically, for each pixel circuit P arranged in a matrix, the write scanning lines 104WS_1 to 104WS_n for n rows driven by the write scanning unit 104 with the write drive pulse WS and the drive scanning unit Power supply lines 105DSL_1 to 105DSL_n for n rows driven by the power supply drive pulse DSL by 105 are wired for each pixel row.

The writing scanning unit 104 and the driving scanning unit 105 are configured by combinations of logic gates (including latches and shift registers), and select each pixel circuit P of the pixel array unit 102 in units of rows, that is, drive signal generation Each pixel circuit P is sequentially selected through the write scanning line 104WS and the power supply line 105DSL based on the vertical drive system pulse signal supplied from the unit 200.
The horizontal drive unit 106 is configured by a combination of logic gates (including latches and shift registers), and selects each pixel circuit P of the pixel array unit 102 in units of columns, that is, supplied from the drive signal generation unit 200. Based on the pulse signal of the horizontal drive system, a predetermined potential in the video signal Vsig is sampled and written to the storage capacitor via the video signal line 106HS for the selected pixel circuit P.

  The display device 1 of the present embodiment is capable of line-sequential driving or dot-sequential driving, and the writing scanning unit 104 and the driving scanning unit 105 of the vertical driving unit 103 are pixels in line sequential (that is, in units of rows). The array unit 102 is scanned, and in synchronization with this, the horizontal drive unit 106 outputs the image signal for one horizontal line simultaneously (in the case of line sequential) or in units of pixels (in the case of dot sequential). Write to 102.

  In order to achieve color image display, the pixel array unit 102 includes, for example, sub-colors (three primary colors of R (red), G (green), and B (blue) in this example) as shown in FIG. 1A. Pixel circuits P_R, P_G, and P_B are provided in the form of vertical stripes in a predetermined arrangement order as pixels. One set of color sub-pixels (pixel circuits P_R, P_G, P_B) constitutes one color pixel. Here, as an example of the subpixel layout, a stripe structure in which subpixels of each color are arranged in a vertical stripe shape is shown, but the subpixel layout is not limited to such an arrangement example. You may employ | adopt the form which shifted the sub pixel to the orthogonal | vertical direction.

  Further, a form in which the color position in one pixel is switched for each pixel in the horizontal direction may be adopted. In the present embodiment, the vertical aperture shift of the sub-pixels and the color position shift within one pixel are used to improve the pixel aperture ratio and the strength of the shadow mask (painting mask). The form of shifting the sub-pixel position and the shadow mask using it will be described in detail later.

  1 and 1A show a configuration in which each element (the writing scanning unit 104 and the driving scanning unit 105) of the vertical driving unit 103 is disposed only on one side of the pixel array unit 102, the vertical driving unit. It is also possible to adopt a configuration in which each element 103 is arranged on both the left and right sides of the pixel array unit 102. Further, as shown in FIG. 1A, it is possible to adopt a configuration in which one and the other of the elements of the vertical drive unit 103 are arranged separately on the left and right.

  Similarly, FIGS. 1 and 1A show a configuration in which the horizontal driving unit 106 is arranged only on one side of the pixel array unit 102, but the horizontal driving units 106 are arranged on both upper and lower sides with the pixel array unit 102 interposed therebetween. It is also possible to adopt a configuration.

  In this example, pulse signals such as shift start pulses SPDS, SPWS, vertical scanning clocks CKDS, CKWS, horizontal start pulse SPH, horizontal scanning clock CKH are input from the outside of the display panel unit 100. A drive signal generation unit 200 that generates timing pulses can be mounted on the display panel unit 100.

<Pixel circuit>
FIG. 2 is a diagram illustrating a configuration example of the pixel circuit P of the display device 1 of the present embodiment and an embodiment of an organic EL display device including the pixel circuit P. The pixel circuit P of the present embodiment shown in FIG. 2 is basically composed of an n-channel thin film field effect transistor and a drive transistor. In addition, a circuit for suppressing fluctuations in the drive current Ids to the organic EL element due to deterioration over time of the organic EL element, that is, driving by correcting a change in current-voltage characteristics of the organic EL element which is an example of an electro-optical element A drive signal stabilization circuit (part 1) that maintains the current Ids constant is provided, and a threshold correction function and mobility correction function that prevents drive current fluctuations due to drive transistor characteristic fluctuations (threshold voltage fluctuations and mobility fluctuations) are realized. Thus, a driving method for maintaining the driving current Ids constant is adopted.

  As a method of suppressing the influence on the drive current Ids due to the characteristic variation of the drive transistor 121 (for example, variation or fluctuation in threshold voltage, mobility, etc.), the 2TR configuration drive circuit is used as it is as a drive signal stabilization circuit (part 1). This is dealt with by devising the drive timing of the transistors 121 and 125 while adopting them.

  The pixel circuit P of the present embodiment has a 2TR drive configuration, and since the number of elements and the number of wirings is small, in addition to being able to achieve high definition, sampling can be performed without deterioration of the video signal Vsig. Can be obtained.

  The pixel circuit P of the present embodiment is characterized by the connection mode of the storage capacitor 120, and is an example of a drive signal stabilization circuit (part 2) as a circuit that prevents drive current fluctuations due to deterioration with time of the organic EL element 127. A bootstrap circuit is configured. A drive signal stabilization circuit (part 2) that realizes a bootstrap function that makes the drive current constant even when the current-voltage characteristics of the organic EL element change with time (prevents fluctuations in the drive current) is provided.

  Further, the pixel circuit P of the present embodiment includes an auxiliary capacitor related to the write gain, the bootstrap gain, and the mobility correction period. However, it is not essential to provide this auxiliary capacity. The basic control operation for driving the pixel circuit P of the present embodiment is the same as that for the pixel circuit P that does not include an auxiliary capacitor.

  MOS transistors are used as the transistors including the drive transistor. In this case, for the drive transistor, the gate end is handled as the control input end, and either the source end or the drain end (here, the source end) is handled as the output end, and the other is the power supply end (here, the drain end). ).

  Specifically, as illustrated in FIG. 2, the pixel circuit P of the present embodiment includes an n-channel driving transistor 121 and a sampling transistor 125, and an organic EL that is an example of an electro-optical element that emits light when current flows. Element 127. In general, since the organic EL element 127 has a rectifying property, it is represented by a diode symbol. The organic EL element 127 has a parasitic capacitance Cel. In the figure, this parasitic capacitance Cel is shown in parallel with the organic EL element 127 (diode-like one).

  The drive transistor 121 has a drain end connected to the power supply line DSL that supplies the first power supply potential, and a source end (output end) S connected to the anode end A of the organic EL element 127 (the connection point is the node ND121). The cathode terminal K of the organic EL element 127 is connected to the ground wiring Vcath (GND) common to all the pixels for supplying the reference potential.

  The ground wiring Vcath may be only a single-layer wiring (upper layer wiring) for the ground wiring Vcath. For example, an auxiliary wiring for the cathode wiring is provided on the anode layer where the wiring for the anode is formed, and the resistance of the cathode wiring is set. The value may be reduced. The auxiliary wiring is wired in a grid shape, a column, or a row in the pixel array portion 102 (display area), and has the same potential as the upper layer wiring and a fixed potential.

  The sampling transistor 125 has a gate terminal G connected to the writing scanning line 104WS from the writing scanning unit 104, a drain terminal connected to the video signal line 106HS, and a source terminal S connected to the gate terminal G of the driving transistor 121. (The connection point is referred to as node ND122). The gate terminal G of the sampling transistor 125 is supplied with an active H write drive pulse WS from the write scanning unit 104. The sampling transistor 125 may have a connection mode in which the source end S and the drain end are reversed.

  The drain end of the drive transistor 121 is connected to the power supply line 105DSL from the drive scanning unit 105 that functions as a power scanner. The power supply line 105 DSL itself has a power supply capability to the drive transistor 121.

  The drive scanning unit 105 has a first voltage Vcc_H on the high voltage side corresponding to the power supply voltage and a second voltage Vcc_L on the low voltage side used for the preparatory operation prior to threshold correction with respect to the drain terminal of the drive transistor 121. (Initialization voltage or initial voltage Vini).

  By driving the drain end side of the driving transistor 121 with a power supply driving pulse DSL that takes two values of the first potential Vcc_H and the second potential Vcc_L, it is possible to perform a preparatory operation prior to threshold correction. The second potential Vcc_L is a potential that is sufficiently lower than the reference potential Vo (also referred to as offset voltage Vofs) of the video signal Vsig in the video signal line 106HS. Specifically, the gate-source voltage Vgs of the drive transistor 121 (the difference between the gate potential Vg and the source potential Vs) is larger than the threshold voltage Vth of the drive transistor 121. Two potential Vcc_L is set. The reference potential Vo (Vofs) is used for the initialization operation prior to the threshold correction operation and also used for precharging the video signal line 106HS in advance.

  In such a pixel circuit P, when driving the organic EL element 127, the first potential Vcc_H is supplied to the drain terminal of the driving transistor 121, and the source terminal S is connected to the anode terminal A side of the organic EL element 127. Thus, a source follower circuit is formed as a whole.

  When such a pixel circuit P is employed, a 2TR driving configuration using one switching transistor (sampling transistor 125) for scanning in addition to the driving transistor 121 is adopted, and a power supply driving pulse DSL for controlling each switching transistor is used. In addition, the setting of the on / off timing of the write drive pulse WS has an influence on the drive current Ids due to deterioration with time of the organic EL element 127 and fluctuations in characteristics of the drive transistor 121 (for example, variations and fluctuations in threshold voltage and mobility). prevent.

  In addition, in the display device 1 of the present embodiment, for each pixel circuit P, a node ND121 (a connection point between the source terminal S of the driving transistor 121 and one terminal of the storage capacitor 120 and the anode terminal A of the organic EL element 127). An auxiliary capacitor 310 that is a capacitor element having a capacitance value Csub is added to the other terminal, and the connection point of the other terminal (referred to as node ND310) of the auxiliary capacitor 310 is used as the power supply line 105DSL of the own row (own stage). The auxiliary capacitor 310 is electrically connected in parallel with the organic EL element 127 (its parasitic capacitance Cel).

  The node ND310 is connected to, for example, a ground wiring Vcath (may be an upper layer wiring or an auxiliary wiring) common to all the pixels to which the cathode ends K of all the organic EL elements 127 are connected. In addition, for example, the node ND310 may be connected to the power supply line 105DSL of its own stage (row), the power supply line 105DSL other than its own stage (row), or any value (grounding) It is also possible to use a fixed potential (including potential). Depending on the connection point of the node ND310, there are advantages and disadvantages (advantages and disadvantages), but the explanation is omitted here.

  By adjusting the capacitance value Csub of the auxiliary capacitor 310, the write gain Ginput and the bootstrap gain Gbst can be adjusted. Also, white balance can be achieved by relatively adjusting the capacitance value Csub between the three RGB pixels. In addition, by adding the auxiliary capacitor 310, the time (mobility correction time) required to correct the mobility μ can be adjusted without affecting the threshold value correction operation.

  By the way, in the display device 1 corresponding to color image display, when forming the color-specific openings in the pixel array unit 102 (substantially the color-dedicated organic layers of the laminated portion of the anode electrode, the organic layer, and the cathode electrode), As a matter of course, it is necessary to form an opening for each color. Therefore, an opening is provided for each color by applying an organic material for each sub-pixel, that is, an organic material for each color, for each color. In this way, a shadow mask is generally used when painting the subpixels by color. However, there is a problem that the pixel aperture ratio is lowered in the arrangement state of the openings in the conventional shadow mask. Hereinafter, this problem and its improvement method will be described in detail.

<< About the problem of pixel aperture >>
3 to 5B are diagrams for explaining the problems related to the pixel aperture of the pixel array unit 102. Here, FIG. 3 is a diagram illustrating the arrangement of the organic EL element 127, the auxiliary capacitor 310, and the like. Specifically, FIG. 3 is a diagram showing an outline of a layer structure for one pixel in a general organic EL display device. Here, FIG. 3A is a plan view for one pixel, and FIG. 3B is a cross-sectional view taken along line AA ′ in FIG. FIG. 4 is a diagram showing a layout of the first comparative example of the lower electrode and the auxiliary wiring of the organic EL element 127. FIG. 4A is a diagram showing a layout of a second comparative example which is a modified example with respect to FIG.

  FIG. 5 is a diagram showing an example of the color arrangement of the three primary colors (R, G, B) for displaying a color image and an example of the pixel aperture arrangement. FIG. 5A is a diagram illustrating an example of a shadow mask (slit mask) provided with slit-shaped openings. FIG. 5B is a diagram illustrating an example of a shadow mask (mask for each vertical stripe pixel) in which an opening is provided for each pixel.

  As shown in the plan view for one pixel shown in FIG. 3A, a lower electrode (for example, an anode electrode) 504 is disposed on the substrate 101, and an opening (hereinafter referred to as an EL opening) of the organic EL element 127 is formed on the lower electrode 504. 127a) is formed. The lower electrode 504 is provided with a connection hole (for example, TFT-anode contact) 504a, and is connected to the input / output terminal (source electrode in this example) of the drive transistor 121 disposed below the lower electrode 504 through the connection hole 504a. An electrode 504 is connected.

  The periphery of the lower electrode 504 is covered with an insulating film pattern 505 so that only a portion where the lower electrode 504, the organic layer 506, and the upper electrode 508 constituting the organic EL element 127 are stacked becomes a light emission effective region 127b. The exposed EL opening 127a is formed.

  FIG. 3B is a cross-sectional view taken along line A-A ′ in FIG. As shown in FIG. 3B, at a position corresponding to each pixel circuit P on the substrate 101, a thin film transistor Q such as a driving transistor 121 and a sampling transistor 125, a storage capacitor 120 (capacitance value Cs), and the like that constitute the pixel circuit. A circuit element such as the auxiliary capacitor 310 (capacitance value Csub) is provided with an internal wiring, and interlayer insulating films 502a and 502b (oxide film) are provided above the layer (first wiring layer L1) (the circuit element in the figure). Only a part of

  A source electrode line and a drain electrode line connected to the thin film transistor Q are provided further above the interlayer insulating film 502. Further, another wiring constituting the pixel circuit P is formed by the conductive layer constituting each element (thin film transistor Q, storage capacitor 120) and the conductive layer constituting the source electrode line and the drain electrode line.

  Then, an interlayer insulating film 503 that functions as an upper planarizing film is provided in a state of covering the layers (second wiring layer L2) such as the source electrode line and the drain electrode line, and an organic EL is formed on the interlayer insulating film 503. An element 127 is formed. The organic EL element 127 includes a lower electrode (for example, an anode electrode) 504, an organic layer 506, and an upper electrode (for example, a cathode electrode) 508 that are sequentially stacked from the lower layer side. Since the organic EL element 127 has a structure in which an organic layer 506 that is a dielectric is sandwiched between the lower electrode 504 and the upper electrode 508, the organic EL element 127 has a capacitance component (parasitic capacitance Cel).

  Specifically, the organic layer 506 has a multilayer structure made of, for example, a low molecular material. For example, a hole injection layer, a hole transport layer, and a light emitting layer are sequentially arranged from the lower electrode 504 side to the upper electrode 508 side. Layer, and an electron transport layer (also serving as an electron injection layer). And in the case of a color display correspondence, the thing suitable for a display color is used as an organic material of a light emitting layer.

  The lower electrode 504 is patterned as a pixel electrode, and is connected to the source electrode 121 s of the driving transistor 121 through a connection hole 504 a formed in the interlayer insulating film 502. In addition, the upper electrode 508 facing the lower electrode 504 is formed as a solid film covering all the pixel circuits P.

  In the organic EL display device 1 having such a layer structure, the organic EL element 101 can be configured as a so-called top emission method in which the emitted light L1 is extracted from the side opposite to the substrate 101 on which the organic EL elements 127 are arranged. Effective in securing the aperture ratio. Further, in such a top emission method, the aperture ratio of the organic EL element 127 does not depend on the layout of the thin film transistor Q constituting the pixel circuit P. For this reason, a pixel circuit P using a plurality of thin film transistors Q and storage capacitors 120 can be arranged corresponding to each pixel.

  The lower electrodes 504 are arranged in a matrix corresponding to the arrangement of the pixel circuits P (see FIGS. 4 and 4A). An auxiliary wiring 505 (auxiliary electrode) composed of the same layer as the lower electrode 504 is wired between adjacent pixels of the lower electrode 504. The auxiliary wiring 505 is electrically connected to the cathode wiring of the upper electrode 508.

  The first wiring layer L1 provided first on the substrate 101 (not shown) is also used as a layer for forming circuit elements such as the thin film transistor Q (the driving transistor 121 and the sampling transistor 125). For example, in the storage capacitor 120 (capacitance value Cs), one electrode is formed on the first wiring layer L1, and the electrode facing it is formed between the interlayer insulating films 502a and 502b with polysilicon. In the auxiliary capacitor 310 (capacitance value Csub), one electrode is formed in the first wiring layer L1 and the second wiring layer L2, and the electrode facing them is formed of polysilicon between the interlayer insulating films 502a and 502b. .

  The first auxiliary capacitor 310a is formed of the electrode of the first wiring layer L1 and polysilicon, the second auxiliary capacitor 310b is formed of the electrode of the second wiring layer L2 and polysilicon, and the electrode of the first wiring layer L1 Since the electrodes of the second wiring layer L1 are connected by contacts, the first auxiliary capacitor 310a and the second auxiliary capacitor 310b are connected in parallel. Note that it is not essential to use the auxiliary capacitor 310b, and only the auxiliary capacitor 310a formed of the electrode of the first wiring layer L1 and the polysilicon may be used similarly to the storage capacitor 120. Of course, it is possible to adopt a configuration in which the auxiliary capacitor 310 itself is not used.

  Since the display device 1 is a top emission type in which emitted light is extracted from the side opposite to the substrate 101, the lower electrode 504 is made of a material having high light shielding properties and high reflectance. On the other hand, the upper electrode 508 is configured using a material having high light transmittance. Therefore, the wiring resistance of the upper electrode 508 is increased. Even if the upper electrode 508 is a solid wiring, there is a limit in reducing the resistance value. The auxiliary wiring 505 contributes to reducing the resistance value of the entire cathode wiring by wiring in parallel with the high resistance upper electrode 508 in electrical circuit. Although not shown, a light shielding metal layer is provided on the surface of the substrate 101 opposite to the side on which the transistor Q and the organic EL element 127 are disposed for light leakage and temperature diffusion.

  For example, the layout of the first comparative example of the lower electrode of the organic EL element 127 and the auxiliary wiring is shown in FIG. As shown in this figure, the lower electrode 504 is arranged in a grid so as to surround the pixel circuit P in correspondence with the arrangement of the pixel circuits P arranged in a matrix, and further on the outer periphery, the pixel array unit 102. It is arranged to surround the whole. Then, an auxiliary wiring 505 composed of the same layer as the lower electrode 504 is wired between the lower electrodes 504. As described above, the auxiliary wiring 505 of the anode layer L3 on which the lower electrode 504 is formed has the cathode contact KC at an appropriate location (in the example shown in the figure, the center between the pixels and the center corresponding to the peripheral pixels). Thus, the upper electrode 508 of the upper layer is connected.

  In order to connect the node of the auxiliary capacitor 310 to the cathode wiring of the organic EL element 127, the electrode of the first wiring layer L1 and the electrode of the second wiring layer L1 are further connected to the auxiliary wiring 505 by a contact. The upper electrode 508 is connected.

  In the layout of the second comparative example shown in FIG. 4A, in the case of a high-definition pixel structure using the top emission method, the auxiliary wiring 505 is surrounded by the entire pixel array unit 102 in order to increase the pixel aperture ratio. A layout in which the wiring is arranged in a lattice shape, a column, or a row in the pixel array portion 102 (display area) is not used.

  For example, as shown in FIG. 5, as a general subpixel layout, a stripe structure is known in which subpixels of the same color are arranged in a line in the vertical direction at a pixel opening interval W0. In addition, in a high-definition pixel, an auxiliary wiring layout in the pixel may not be used in order to increase the aperture ratio.

  In a stripe structure in which sub-pixels for each color are formed for color image display with a structure without an auxiliary wiring, conventionally, all of the sub-pixels of any one color are generally long for each pixel in the same column in the vertical direction. A slit mask 600 as shown in FIG. 5A in which a scale-like opening 602 is provided at a pixel pitch is used. However, such a slit mask 600 is liable to cause slack and the like and has a low strength, and it is particularly difficult to obtain a mask alignment accuracy in the horizontal direction. This problem becomes more apparent as the panel size increases. In order to solve this problem, if the design is made in consideration of the mask shift, it is necessary to make the subpixels have a more elongated shape, and the pixel aperture ratio is lowered.

  On the other hand, in order to achieve a high aperture ratio with high definition, openings 612 are provided in vertical stripes in the vertical direction for each subpixel as shown in FIG. 5B, and the pixel pitch in the horizontal direction. In some cases, the mask 610 is used for each vertical stripe pixel provided. Such a mask structure includes a spacing portion 614 that bridges the horizontal direction (mask lateral direction) between the pixels in the vertical direction (vertical direction). The mask structure is provided with an interval portion 614 for each pixel, so that it is possible to eliminate the difficulty that the slit mask 600 is likely to be slack in the lateral direction, and a mask having high strength can be obtained.

  However, on the other hand, the vertical stripe pixel-by-pixel mask 610 requires an interval portion 614 for each pixel in the vertical direction, which causes a decrease in aperture ratio. In a subpixel having a low aperture ratio, the aperture density is increased, and in order to increase the luminance, a large current must be passed through the narrow aperture, and as a result, the lifetime is deteriorated.

  As described above, the conventional shadow mask cannot satisfy both the strength and the aperture ratio. In high-definition panels, development of a high-strength shadow mask that can secure a high aperture ratio sufficient for the lifetime of the EL element is required.

<Improvement Method: First Embodiment>
6 and 6A are diagrams illustrating a first embodiment of a technique for improving the strength of a shadow mask (evaporation mask) and the pixel aperture ratio. Here, FIG. 6 is a diagram showing the color arrangement and pixel opening arrangement of the three primary colors (R, G, B) for color image display in the display panel unit 100A of the first embodiment. FIG. 6A is a diagram showing a shadow mask 620A of the first embodiment that can improve the strength and the aperture ratio.

  The color arrangement and pixel aperture arrangement in the display panel unit 100 of this embodiment, including the second and third embodiments described later, are focused on the same colors of R, G, and B, and the subpixel position is horizontal for each row. It is characterized in that it is shifted in the direction sequentially. When viewed by color, the difference from the conventional vertical stripe structure is that the subpixel positions of the same color are arranged in an oblique direction without adopting a stripe structure for any color.

  A shadow mask 620 for forming the display panel unit 100 of the present embodiment having such a color arrangement and a pixel opening arrangement includes openings corresponding to subpixels shifted by a predetermined amount for each row, and has the same color. Similar to the sub-pixel position being in the diagonal direction, the opening is arranged in the diagonal direction so that a gap is formed between the diagonal openings to form a bridge between the vertical and horizontal directions. Make. Each opening has a shape and a size corresponding to the EL opening 127a of the organic EL element 127 for a certain color of the pixel array portion.

  In this way, conventionally, an interval portion that bridges in the horizontal direction is provided for each pixel in the vertical direction, whereas in this embodiment, an interval portion that bridges in the oblique direction is provided for each pixel. The structure is provided. Unlike the slit mask 600, the gap portion that forms the bridge in the diagonal direction is surely present in the same manner as the mask 610 for each vertical stripe pixel, so that the problem of mask strength does not occur, and the same level as the mask 610 for each vertical stripe pixel. You can think that you can. A vapor deposition mask having a high strength can be used, and a high aperture ratio and high definition of a pixel can be realized.

  Here, various forms can be adopted depending on how the shift amount in the horizontal direction of the sub-pixels in each row is set. The first to third embodiments to be described later are each aspect focusing on this point. For example, the first embodiment is different from the third embodiment described later in that the RGB sub-pixel arrangement is shifted and arranged at the sub-pixel arrangement pitch for each row. Of course, the shadow mask 620A corresponding to this is also arranged so that the openings and the intervals are arranged in an oblique direction.

  In this case, when viewed by color, all colors do not adopt a stripe structure, and the sub-pixel position of the same color is oblique, but when viewed ignoring the color (regardless of color), the conventional vertical stripe structure Similar to the above, it is characterized by a vertical stripe structure. In the third embodiment to be described later, the sub-pixel position is different from the oblique direction even when the color is ignored.

  The difference between the first embodiment and the second embodiment, which will be described later, is that the sub-pixel positions of the same color are arranged in a line in the diagonally lower right direction. For example, the example shown in FIG. 6 shows a color arrangement example of subpixels for a total of 8 pixels of 4 rows * 2 columns in the display panel unit 100A. When attention is paid to subpixels of the same color, the subpixels of the same color are arranged in a line in the diagonal direction from the upper left to the lower right by shifting to the right at the subpixel pitch for each row. As a result, the sub-pixels of the same color are arranged so as not to be continuous in the vertical direction (vertical direction). The pixel interval of each row can be narrowed to the limit, and the vertical pixel aperture can be increased to the limit. Here, “extreme” means the extent to which adjacent pixels in the vertical direction (no matter the color) are not in contact.

  An example of the shadow mask 620A of the first embodiment corresponding to the display panel unit 100A having the color arrangement and the pixel opening arrangement shown in FIG. 6 is shown in FIG. 6A. In the shadow mask 620A of the first embodiment, the openings 622 are arranged in the oblique direction from the upper left to the lower right, in the same manner as the sub-pixels of the same color are arranged in the oblique direction from the upper left to the lower right. That is, the mask has an opening in the diagonally lower right direction. Since the openings corresponding to the sub-pixels of the same color are not continuous in the vertical direction, the vertical mask interval (pixel interval W2_V) can be reduced to the limit, and the vertical pixel opening can be increased to the limit. . Here, “extreme” means the extent to which adjacent pixels in the vertical direction (no matter the color) are not in contact. However, it should be noted that the horizontal spacing portion 624_H of the shadow mask 620A is narrower than in a third embodiment described later.

  In such a mask structure, the interval in the vertical direction is approximately the pixel pitch, and the mask strength against pulling in the vertical direction can be sufficiently increased. Further, the horizontal interval is also a pixel pitch, and the mask strength against the horizontal pull can be sufficiently increased. Further, since the interval portion 624 is provided for each pixel in the oblique direction, it is considered that the mask strength against pulling in the oblique direction can be equal to that of the mask 610 for each vertical stripe pixel.

  As a result, as shown in FIG. 6, in the pixel without the auxiliary wiring, the opening can be enlarged in the vertical direction (vertical direction) as compared with the conventional case. In addition, the mask can be pulled in two directions, the vertical direction and the horizontal direction, and the strength thereof can be set to the same level as that of the mask 610 for each vertical stripe pixel. It becomes easy.

  As described above, according to the color arrangement and pixel opening arrangement in the display panel unit 100A of the first embodiment and the shadow mask 620A of the first embodiment corresponding thereto, the vertical stripe pixel-by-pixel mask 610 as compared with the conventional slit mask 600. Similarly, the presence of the interval portion 624 can increase the strength of the mask and can provide a high-strength mask that can improve the deflection. Further, since the sub-pixel position of the same color is shifted diagonally to the lower right for each row, the vertical mask interval (pixel interval W2_V) can be narrowed to the limit, and the vertical pixel interval can be narrowed to the limit. Even in such a case, the advantage of the third embodiment is that the horizontal spacing 624_H of the first and shadow masks 620C can be made wider than that of the first and second embodiments.

  Thereby, the fall of the aperture ratio resulting from vapor deposition for forming EL opening part 127a can be suppressed, and a high aperture ratio can be achieved with high strength in a high-definition panel. When making a large-sized panel, a high aperture ratio becomes possible after using a strong shadow mask 620A, and even in a high-definition panel, a sufficient aperture ratio can be secured for the life of the EL element, High definition panel can be achieved.

<Improvement Method: Second Embodiment>
FIG. 7 and FIG. 7A are diagrams for explaining a third embodiment of a technique for improving the strength of a shadow mask (evaporation mask) and the pixel aperture ratio. Here, FIG. 7 is a diagram showing the color arrangement and pixel opening arrangement of the sub-pixels of the three primary colors (R, G, B) for color image display in the display panel unit 100B of the second embodiment. FIG. 7A is a diagram showing a shadow mask 620B of the second embodiment that can improve the strength and the aperture ratio.

  In the second embodiment, unlike the first embodiment, the sub-pixel positions of the same color are arranged in a line in the diagonally lower left direction. For example, the example shown in FIG. 7 shows a color arrangement example of subpixels for a total of 8 pixels of 4 rows * 2 columns in the display panel unit 100B. When paying attention to the same color, each row is shifted leftward at the subpixel pitch, and the subpixels of the same color are arranged in a line in the diagonal direction from the upper right to the lower left. As a result, similar to the first embodiment, sub-pixels of the same color are not continuous in the vertical direction (up and down direction).

  An example of the shadow mask 620B of the second embodiment corresponding to the display panel portion 100B having the color arrangement and the pixel opening arrangement shown in FIG. 7 is shown in FIG. 7A. In the shadow mask 620B of the second embodiment, the openings 622 and the spacing portions 624 are arranged in the diagonal direction from the upper right to the lower left, in the same manner as the sub-pixels of the same color are arranged in the diagonal direction from the upper right to the lower left. That is, the mask has an opening in the diagonally lower left direction. Similar to the first embodiment, the sub-pixels of the same color are not continuous in the vertical direction, so that the mask interval in the vertical direction can be narrowed to the limit. As in the first embodiment, the pixel interval of each row can be narrowed to the limit, and the vertical pixel aperture can be increased to the limit.

  As a result, as shown in FIG. 7, in the pixel without the auxiliary wiring, the opening can be enlarged in the vertical direction as compared with the conventional case. In addition, the mask can be pulled in two directions, the vertical direction and the horizontal direction, and the strength thereof can be set to the same level as that of the mask 610 for each vertical stripe pixel. It becomes easy.

  As described above, the color arrangement and pixel opening arrangement in the display panel unit 100B of the second embodiment and the shadow mask 620B of the second embodiment corresponding thereto correspond to the sub-pixels of the same color in the pixel array unit 102 and the openings of the shadow mask 620B. The basic mechanism is the same only in that the diagonal shift direction of 622 is opposite to that in the first embodiment, and the same effect as in the first embodiment can be enjoyed. Compared to the conventional slit mask 600, the presence of the interval portion 624 can increase the strength of the mask due to the presence of the interval portion 624 in the same manner as the mask 610 for each vertical stripe pixel, and can be a high-strength mask that can improve the deflection. Further, since the sub-pixel position of the same color is shifted diagonally to the lower right for each row, the vertical mask interval can be narrowed to the limit, and the vertical pixel interval can be narrowed to the limit.

<Improvement Method: Third Embodiment>
FIG. 8 and FIG. 8A are diagrams for explaining a third embodiment of a technique for improving the strength of a shadow mask (evaporation mask) and the pixel aperture ratio. Here, FIG. 8 is a diagram showing the color arrangement and pixel opening arrangement of the three primary colors (R, G, B) for color image display in the display panel unit 100C of the third embodiment. FIG. 8A is a diagram showing a shadow mask 620C of the third embodiment that can improve the strength and the aperture ratio.

  In the first and second embodiments described above, when paying attention to the same color, the subpixels are arranged by shifting at a subpixel pitch for each row in an oblique direction from upper left to lower right (or from upper right to lower left). However, the third embodiment is characterized in that each subpixel is arranged by shifting the pixel center for each row at a 0.5 subpixel pitch. In other words, it is characterized in that each subpixel is arranged by shifting subpixels of the same color for each row at a pitch of 0.5 pixels (equivalent to 1.5 subpixel pitch in this example). Therefore, the arrangement of R, G, and B is different every other line.

  In this way, even if the color is ignored, the sub-pixels are shifted with a 0.5 sub-pixel pitch. As a result, the vertical stripe structure is not taken even when the color is ignored. The subpixel position is an oblique direction. When focusing on sub-pixels of the same color, they may be arranged in a staggered pattern (zigzag) without being continuous in the vertical direction, and the sub-pixels of the same color are arranged uniformly, that is, arranged in a checkered pattern. I understand. As a result, the sub-pixels of the same color are not continuous in the vertical direction (vertical direction), and the distance for each sub-pixel of the same color can be maximized.

  An example of the shadow mask 620B of the third embodiment corresponding to the display panel portion 100B having the color arrangement and the pixel opening arrangement shown in FIG. 8 is shown in FIG. 8A. In the shadow mask 620B of the third embodiment, the openings 622 are equally arranged in a checkered pattern in the same manner as the sub-pixels of the same color are arranged in a checkered pattern. In other words, the mask has a corresponding gap 624 in the diagonally lower left direction and diagonally lower right direction, and an opening is formed. As in the first and second embodiments, the sub-pixels of the same color are not continuous in the vertical direction, so that the mask interval in the vertical direction can be narrowed to the limit.

  Since the vapor deposition mask opening (opening 622) is arranged in a perfect checkered pattern, the diagonal spacing 624 can be made wider than in the first and second embodiments, and the mask strength against tensile pulling in the diagonal direction can be increased. The deposition mask can be further increased and has a higher strength. Since the distance for each sub-pixel can be maximized, the opening 622 can be opened 100%, and the mask strength is high at the same time.

  Thus, the color arrangement and pixel opening arrangement in the display panel unit 100C of the third embodiment and the shadow mask 620C of the third embodiment corresponding thereto correspond to the subpixels of the same color in the pixel array unit 102 and the openings of the shadow mask 620B. The point that 622 is shifted in the oblique direction is the same as the first and second embodiments, and the same effect as the first and second embodiments can be enjoyed. In addition, since the gap portion 624 can be made wider than in the first and second embodiments, it is possible to form a vapor deposition mask with extremely high strength, and in a panel having a size larger than that in the first and second embodiments, a high aperture of the pixel. It will be able to respond sufficiently to achieve higher rates and higher definition.

<Film formation process>
FIG. 9 illustrates a procedure for forming the display panel unit 100 (100A, 100B, 100C: in particular the EL opening 127a) of the present embodiment using the shadow mask 620 (620A, 620B, 620C) of the present embodiment. It is a flowchart.

  When the organic light emitting layer of the display panel unit 100 of this embodiment is formed, the position of the spacing portion 624 of the shadow mask 620 is classified by color (for example, in the order of R → G → B) in each color forming step. Is arranged so as to correspond to the position of the sub-pixel (specifically, the EL opening 127a) of the desired color in the display panel unit 100, so that the EL opening 127a (specifically, organic layer) of the desired color is arranged. 506) will be formed. When the EL opening 127a of another color is formed, each time the target color is switched in the order of R → G → B, for example, the opening 622 of the shadow mask 620 is equivalent to the arrangement pitch of the subpixels (electro-optical elements). The position may be shifted in the horizontal direction.

  That is, since a low molecular system is adopted as the organic material of the organic layer 506 forming the organic EL element 127 at the stage of attaching the thin film, in order to form films such as an injection layer, a transport layer, and a light emitting layer, Adopt a vacuum deposition method. The vacuum vapor deposition method includes various methods such as a resistance heating vapor deposition method and an electron beam vapor deposition method in detail. In this example, a description will be given by a resistance heating vapor deposition method which is a relatively simple method.

  In the resistance heating vapor deposition method, as shown in FIG. 9, an intermediate substrate X in which circuit elements such as TFTs and capacitive elements and a lower electrode 504 are patterned is set on a base (substrate holder) of a vacuum chamber of a vapor deposition machine ( (Normally downward), a low molecular material for forming a thin film is put in a crucible and the inside of the chamber is evacuated. Thereafter, the filament is energized to heat the crucible, and the low molecular weight material is sublimated (vaporized / gasified) to float in the vapor deposition machine, and is attached as a film to the intermediate substrate X set on the upper part. At this time, the hole injection layer (S112) → the hole transport layer (S114) → the light emitting layer (S116) → the electron transport layer (S118) are formed so that the stacking order is from the lower electrode 504 to the upper electrode 508. Finally, the upper electrode 508 is formed (S120).

  Here, in order to achieve full color display panel 100, after the hole injection layer and the hole transport layer are deposited on the pixel position using the first metal mask 620Z provided with the opening in the pixel unit. For the light emitting layer, it is necessary to coat organic pigments of the three primary colors of RGB, for example, within a narrow range. For this RGB color separation, the shadow mask 620 of the present embodiment different from the first metal mask 620Z is used. R, G, and B dyes (organic material = light-emitting layer) are vapor-deposited only on the portion where the opening 622 of the shadow mask 620 is provided.

  Specifically, a thin metal plate (shadow mask 620) provided with an opening 622 is placed in front of the intermediate substrate X, and the opening 622 of the shadow mask 620 is placed at the position of the R color subpixel of the display panel 100. (S115R), and an organic material for R color is deposited (S116R). As a result, an organic layer 506 (light emitting layer) for R color is formed collectively on the red subpixel portion of the pixel array unit 102.

  Thereafter, the shadow mask 620 is shifted in the horizontal direction by the sub-pixel pitch, and the opening 622 of the shadow mask 620 is disposed at the position of the G sub-pixel of the display panel unit 100 (S115G). The material is deposited (S116G). As a result, a green organic layer 506 (light emitting layer) is formed collectively on the green sub-pixel portion of the pixel array unit 102.

  Thereafter, the shadow mask 620 is shifted in the horizontal direction by the sub-pixel pitch, and the opening 622 of the shadow mask 620 is disposed at the position of the B-color sub-pixel of the display panel 100 (S115B). The material is deposited (S116B). As a result, a B-color organic layer 506 (light-emitting layer) is collectively formed in the blue sub-pixel portion of the pixel array unit 102.

  As can be understood from the above description, in forming the organic EL element 127 of the pixel array unit 102 in the display panel unit 100 of the present embodiment, a shadow mask having an open film formation window (opening 622) is provided. Since 620 is gradually shifted (subpixel pitch) in the horizontal direction, low molecular organic dyes of R, G, and B are attached, so that the film formation method is the same as a general full color method in a low molecular system. It can be.

  As described above, according to the color arrangement and pixel opening arrangement in the display panel unit 100 of the present embodiment and the shadow mask 620 of the present embodiment corresponding thereto, the vertical stripe pixel-by-pixel mask 610 is the same as the conventional slit mask 600. In addition, the presence of the gap portion 624 increases the strength of the mask and can provide a high-strength mask that can improve deflection. Further, by shifting the sub-pixels of the same color in a diagonal direction with a sub-pixel pitch or 1.5 sub-pixel pitch for each row, the mask strength equal to or higher than that of the conventional vertical stripe pixel mask 610 can be obtained. .

  Thereby, the fall of the aperture ratio resulting from vapor deposition for forming EL opening part 127a can be suppressed, and a high aperture ratio can be achieved with high strength in a high-definition panel. When making a large-sized panel, a high aperture ratio becomes possible after using a strong shadow mask 620, and even in a high-definition panel, a sufficient aperture ratio can be secured for the life of the EL element, High definition panel can be achieved.

  Further, when the EL opening 127a (organic layer 506) is formed, the shadow mask 620 may be shifted only in the horizontal direction as in the case where the mask 610 is used for each vertical stripe pixel, and the control is simple. With one shadow mask 620, the R, G, and B light-emitting layers can be vapor-deposited, and the cost is the same as that of the prior art.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various changes or improvements can be added to the above-described embodiment without departing from the gist of the invention, and embodiments to which such changes or improvements are added are also included in the technical scope of the present invention.

  Further, the above embodiments do not limit the invention according to the claims (claims), and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. Absent. The embodiments described above include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. Even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, as long as an effect is obtained, a configuration from which these some constituent requirements are deleted can be extracted as an invention.

  For example, in the above-described embodiment, the example in which the organic EL element 127 is used as the electro-optical element of the pixel circuit P has been described. However, the present invention is not limited to this example, and the amount of light emitted from the light emitting layer according to the current value flowing through the element. The present invention can be applied to color display for all display devices using a current-driven electro-optic element that changes.

  In addition, the pixel circuit has been shown as an example of a 2TR configuration having two n-channel type thin film field effect transistors as the number of transistors constituting the pixel circuit and a circuit configuration. However, the “dual theory” is established in circuit theory. The pixel circuit P can be modified from this viewpoint.

  Further, the method of changing the circuit is not limited to this. It does not matter whether or not the 2TR configuration is used, and the number of transistors may be three or more, and the improvement methods of the present embodiment described above can be applied to all of them. In this way, it is possible to apply the idea of this embodiment in which a high aperture ratio of a pixel or a high definition of a panel is achieved using a high-intensity shadow mask.

1 is a block diagram showing an outline of a configuration of an active matrix display device which is an embodiment of a display device according to the present invention. 1 is a block diagram (in the case of a color display mode) showing an outline of a configuration of an active matrix display device which is an embodiment of a display device according to the present invention. It is a figure which shows an example of the pixel circuit used for the display apparatus of this embodiment. It is a figure explaining arrangement | positioning, such as an organic EL element and an auxiliary capacity. It is the figure which showed the layout of the 1st comparative example of the lower electrode of an organic EL element, and auxiliary wiring. It is the figure which showed the layout of the 2nd comparative example which is a modification with respect to FIG. It is a figure which shows an example of the color arrangement | positioning of 3 primary color subpixels for color image display, and an example of pixel opening arrangement | positioning. It is a figure which shows an example of a slit mask. It is a figure which shows an example of a mask for every vertical stripe pixel. It is a figure which shows the color arrangement | positioning and pixel opening arrangement | positioning of 3 primary color subpixels for color image display in the display panel part of 1st Embodiment. It is a figure which shows the shadow mask of 1st Embodiment. It is a figure which shows the color arrangement | positioning and pixel opening arrangement | positioning of three primary color subpixels for a color image display in the display panel part of 2nd Embodiment. It is a figure which shows the shadow mask of 2nd Embodiment. It is a figure which shows the color arrangement | positioning and pixel opening arrangement | positioning of the three primary color subpixels for a color image display in the display panel part of 3rd Embodiment. It is a figure which shows the shadow mask of 3rd Embodiment. It is a figure explaining the procedure which forms the organic light emitting layer of a display panel part using the shadow mask of this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Display apparatus, 100 ... Display panel part, 101 ... Board | substrate, 102 ... Pixel array part, 103 ... Vertical drive part, 104 ... Write scanning part, 105 ... Drive scanning part, 106 ... Horizontal drive part, 109 ... Control part , 120 ... holding capacitor, 121 ... drive transistor, 125 ... sampling transistor, 127 ... organic EL element, 127 a ... EL opening, 130 ... interface part, 133 ... vertical IF part, 136 ... horizontal IF part, 200 ... drive signal generation 220, video signal processing unit, 310 ... auxiliary capacitor, 502 ... interlayer insulating film, 503 ... interlayer insulating film, 504 ... lower electrode, 505 ... auxiliary wiring, 506 ... organic layer, 508 ... upper electrode, 600 ... slit mask , 610 ... Masks for vertical stripe pixels, 620 ... Shadow mask, 622 ... Opening, 624 ... Spacing part

Claims (5)

A pixel array unit having a matrix of electro-optic elements in which the amount of light emitted from the light-emitting layer is changed by a flowing current, and one pixel for color display is configured by a combination of the electro-optic elements for each color; The light-emitting layer of the electro-optic element is formed by arranging the openings of the same shadow mask provided with openings of a predetermined shape in correspondence with the light-emitting layers of a desired color and coating them by color. An image display device,
The positions within one pixel of the electro-optic elements of the same color are sequentially shifted in the horizontal direction of the pixel array portion, and the positions of the electro-optic elements of the same color are arranged in a line in an oblique direction. A color image display device. The pixel center position is shifted by 1/2 pitch with respect to the arrangement pitch of the electro-optic elements in the horizontal direction of the pixel array portion, and the electro-optic elements of the same color are arranged in a checkered pattern. The color image display device according to claim 1. A pixel array unit having a matrix of electro-optic elements in which the amount of light emitted from the light emitting layer is changed by a flowing current, wherein the light emitting layer is formed separately for each color constituting one pixel for color display. A shadow mask used in the manufacture of a color image display device including the pixel array unit including an optical element,
An opening having a shape and a size corresponding to the light emitting layer of the electro-optic element for a certain color is provided;
The shadow mask is characterized in that the openings are arranged in a row so as to correspond to an oblique direction of the pixel array portion. The shadow mask according to claim 3, wherein the openings are equally arranged in a checkered pattern. The pixel array unit includes an electro-optical element in which the amount of light emitted from the light emitting layer is changed by a flowing current, and one pixel for color display is configured by a combination of the electro-optical elements for each color. A method of manufacturing a color image display device by arranging the light emitting layer in the same shadow mask provided with openings of a predetermined shape so that the openings correspond to the light emitting layers of a desired color and are separately applied for each color. Because
The shadow mask is provided with openings having a shape and size corresponding to the light emitting layer of the electro-optic element for a certain color, and the openings are arranged in a row so as to correspond to the oblique direction of the pixel array portion. Has been
Each of the openings of the shadow mask is arranged corresponding to the position of the light emitting layer of the electro-optic element of the desired color of one pixel for color display in the pixel array portion, and the dye of the desired color is arranged A deposition step for each color for depositing the light emitting layer of the desired color by being attached to a substrate;
In the film formation step for each color, each time the desired color is switched, the position of the opening of the shadow mask is shifted in the horizontal direction of the pixel array unit by the arrangement pitch of the electro-optic elements. A method for manufacturing a color image display device.

Images