JP2009229908A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display panel, which includes a light sensor for external light illuminance detection in which self light emitting elements are two-dimensionally arranged, and prevents reflected light from being emitted to a front surface side even when the external light is reflected on the light sensor. <P>SOLUTION: A λ/4 retardation plate and polarization plate arranged on an upper surface of a sealing substrate 32 are extended on an upper part of a region corresponding to the light sensor of an external light illuminance detection circuit 40 formed on one surface of a display substrate 31. External light incident from an external light take-in window 16 and transmitting the polarization plate 34 transmits the λ/4 retardation plate 33 to turn into circular polarized light. The circular polarized light enters a light sensor TFT 41 of the external light illuminance detection circuit 40, and the illuminance of the external light depending on an incident light amount is detected. The reflected light transmitting the λ/4 retardation plate 33 and reflected on the light sensor TFT 41 transmits the λ/4 retardation plate 33 again to turn into linear polarized light. The linear polarized light turns into linear polarized light having a polarized light component orthogonal to a polarization axis of the polarization plate 34, is absorbed at the polarization plate 34, and is not emitted to the front surface side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a display device, and more particularly to a self-luminous display device including a display panel in which self-luminous elements such as organic electroluminescence elements are two-dimensionally arranged.

In recent years, liquid crystal display devices (LCDs) and organic electro-luminescence devices have been used as monitors and displays for personal computers and video equipment, and as display devices for mobile devices such as mobile phones, digital audio players, digital cameras, and electronic dictionaries. A self-luminous display device including a display panel in which self-luminous elements such as luminescence elements (organic EL elements) are two-dimensionally arranged is widely applied.
In particular, a self-luminous display device has excellent display characteristics such as a high display response speed and a small viewing angle dependency compared to a liquid crystal display device, and a backlight or a light guide plate like a liquid crystal display device. Therefore, it is expected to be applied to various electronic devices in the future.
On the other hand, in such a self-luminous display device, if the light emission luminance of the light emitting element is set to a constant luminance adjusted to the product shipment, the display unit is used in an environment where the illuminance of outside light is high, such as outdoors. In some cases, the display section is too bright in a dark environment such as indoors or at night, and the user may feel dazzled. Therefore, in a self-luminous display device such as an organic EL display device, a light sensor for detecting ambient light illuminance is provided in a region other than the display region of the display panel, and display is performed based on the detection result of ambient light illumination by the light sensor There is one in which the luminance of the part is controlled (see, for example, Patent Document 1).

JP 2006-30318 A

  However, in the self-luminous display device as described above, an external light illuminance detection optical sensor provided on the surface of an area other than the display area of the display panel is exposed to the surface side in order to capture external light. Therefore, there has been a problem that external light is reflected by the constituent elements of the optical sensor (for example, an electrode made of a metal material), and the reflected light is emitted to the surface side, which greatly impairs the appearance.

  Therefore, an object of the present invention is to provide an organic EL display device that can prevent the reflected light from being emitted to the surface side even when external light is reflected by the optical sensor.

  The display device according to claim 1, wherein a display substrate having a display region in which a plurality of display pixels having light emitting elements are formed on one surface, and a region different from the display region on the one surface of the display substrate. External light received by the optical sensor is incident on an external light illuminance detection circuit having an optical sensor that detects the illuminance of external light provided, and an area of the display substrate where the optical sensor of the external light illuminance detection circuit is provided. A light-shielding λ / 4 phase difference plate, and a light-shielding polarizing plate provided on the surface side of the light-shielding λ / 4 phase difference plate, the light-shielding λ / 4 phase difference The angle formed by the slow axis of the plate and the polarization axis of the light-shielding polarizing plate is 45 ° ± 1 ° or 135 ° ± 1 °.

According to a second aspect of the present invention, in the display device according to the first aspect, a display λ / 4 retardation plate provided on the light exit surface side of the display region, and the display λ / 4 position A polarizing plate for display provided on the surface side of the phase difference plate, and the light blocking λ / 4 phase difference plate and the display λ / 4 phase difference plate are integrally formed, and the light blocking polarizing plate The plate and the polarizing plate for display are formed integrally.
According to a third aspect of the present invention, in the display device according to the first aspect, a display λ / 4 retardation plate provided on the light emitting surface side of the display region, and the display λ / 4 position A polarizing plate for display provided on the surface side of the phase difference plate, and the light blocking λ / 4 retardation plate and the light blocking polarizing plate, the display λ / 4 phase difference plate, and the display polarizing plate. It is characterized by being provided separately from the plate.

According to a fourth aspect of the present invention, in the display device according to the first aspect, the display device is further provided on a side of the display substrate where the external light received by the optical sensor is incident on the region where the optical sensor is provided. And at least one condensing lens.
According to a fifth aspect of the present invention, in the display device according to the first aspect of the present invention, the display device includes a sealing substrate that covers and seals the display region on the one surface of the display substrate.
According to a sixth aspect of the present invention, in the display device according to the fifth aspect, the light emitted from the light emitting elements in the display area is transmitted from the one surface of the display substrate through the sealing substrate. The light-shielding λ / 4 retardation plate and the light-shielding polarizing plate are emitted in a direction toward the outer surface of the sealing substrate, and are disposed on the one surface of the display substrate above the region where the photosensor is provided. It is provided.

According to a seventh aspect of the present invention, in the display device according to the first aspect, the light emitted from the light emitting elements in the display area is displayed on the display substrate through the display substrate from the one surface of the display substrate. The light-shielding λ / 4 phase difference plate and the light-shielding polarizing plate are emitted from the other surface side facing the one surface of the substrate, and are provided on the other surface of the display substrate.
According to an eighth aspect of the present invention, in the display device according to the seventh aspect, the photosensor has an inverted staggered thin film transistor structure, the photosensor has a gate electrode, and the gate electrode is transparent conductive. It is characterized by comprising a film.

According to a ninth aspect of the present invention, in the display device according to the seventh aspect, the photosensor has a thin film transistor structure, and the photosensor does not have a gate electrode.
The invention according to claim 10 is the display device according to claim 1, wherein at least the display substrate is accommodated therein, a display window is provided in a portion corresponding to the display area of the display substrate, and It has a case which has an external light taking-in window in the part corresponding to a photosensor.

  According to the present invention, external light passes through the light-shielding polarizing plate and the light-shielding λ / 4 phase difference plate and is irradiated to the optical sensor, and this irradiation light is reflected by the optical sensor and the light shielding λ / 4 phase difference plate. When the light is transmitted again, the transmitted light (linearly polarized light) is absorbed by the light-shielding polarizing plate, so that even if external light is reflected by the optical sensor, the reflected light is not emitted to the surface side. Can do.

  FIG. 1 shows a plan view of a main part of a display device 1 as an embodiment of the present invention, and FIG. 2 shows a first structural example of a sectional view taken along line II-II in FIG. 3 shows a second structural example of a cross-sectional view taken along the line II-II in FIG. Here, in FIG.2 and FIG.3, the same code | symbol is attached | subjected about the same or equivalent component. As will be described later, the configuration shown in FIG. 2 corresponds to the case where the organic EL element formed on the display panel 30 has a top emission structure, and the configuration shown in FIG. 3 is formed on the display panel 30. This corresponds to the case where the organic EL element has a bottom emission structure.

  The display device 1 includes a front side case 11 and a back side case 12. The front surface side case 11 and the back surface side case 12 are made of, for example, resin, and the front surface side case 11 and the back surface side case 12 are engaged with each other by the fitting portion 13, and the inside thereof is the display panel storage portion λ / 4. .

  The front side case 11 is provided with side wall portions 18 on four sides of a substantially rectangular frame-shaped portion 17 having a rectangular display window 15 and a rectangular external light capturing window 16. 13 is provided. The back surface side case 12 has a structure in which side walls 20 are provided on four sides of a substantially rectangular plate-like portion 19 and fitting portions 13 are provided on the side walls 20.

  And the side wall part 18 of the surface side case 11 and the side wall part 20 of the back surface side case 12 are fitted by the unevenness | corrugation of both the fitting parts 13. FIG.

  A display panel 30 is housed in the display panel housing portion 14 in the front side case 11 and the back side case 12. The display panel 30 includes a display substrate 31 made of glass, for example, and a sealing substrate 32, and a light emitting element made of an organic EL element is provided on a display region provided on the one surface of the display substrate 31 in accordance with the display window 15. Display pixels PIX having the same are formed. In addition, a semiconductor element 36 for driving the display pixel PIX is mounted in an area near the display area on one surface of the display substrate 31. The sealing substrate 32 is disposed on one surface of the display substrate 31 so as to cover the display region, and is bonded to one surface of the display substrate 31 via, for example, a substantially rectangular frame-shaped sealing material (not shown). Yes. For example, a counterbore (recessed portion: not shown) is formed in a region facing the display pixel PIX formed on the display substrate 31 on the surface of the sealing substrate 32 facing the one surface of the display substrate 31. When the display pixel PIX drives the organic EL element by an active method, the display pixel PIX includes an organic EL element and a pixel drive circuit including a plurality of TFTs (thin film transistors) for driving the organic EL element. , And is configured.

  The structure of the organic EL element is roughly classified into a top emission structure and a bottom emission structure. In the top emission structure, the emission direction of emitted light is set to be opposite to the direction of the substrate on which the organic EL element is formed, and light is emitted upward from the organic EL element. The emission direction of the emitted light is set in the direction of the substrate on which the organic EL element is formed, and the light is emitted through the substrate on which the organic EL element is formed.

  The configuration shown in FIG. 2 shows a configuration in the case where the organic EL element in the display pixel PIX formed on one surface of the display substrate 31 has the above-described top emission structure. In this case, the light emitted by the organic EL element is emitted through the sealing substrate 32 in the direction indicated by the arrow above the drawing. An external light illuminance detection circuit 40 having an optical sensor is formed in a region corresponding to the external light capturing window 16 of the front side case 11 on one surface of the display substrate 31. The configuration of the external light illuminance detection circuit 40 will be described later.

  A λ / 4 phase difference plate (display λ / 4 phase difference plate) 33 and a polarizing plate (display polarizing plate) 34 are provided in a region covering at least the display region on the sealing substrate 32 of the display panel 30. Laminated and provided. With the other surface side corresponding to one surface side of the display substrate 31 of the display panel 30 being in contact with and supported by the inner surface of the back surface side case 12, the upper surface of the polarizing plate 34 is around the outside of the display window 15 of the front surface case 11. By being restrained by the inner surface, the display panel 30 is accommodated in the display panel accommodating portion 14. In addition, a λ / 4 phase difference plate (light blocking λ / 4 phase difference plate) 33 and a polarizing plate (light blocking polarization) are also formed on the upper portion of the display substrate 31 where the light sensor of the external light illuminance detection circuit 40 is formed. Plate) 34 is provided. For example, as shown in FIGS. 1 and 2, the λ / 4 phase difference plate 33 and the polarizing plate 34 provided in the upper part of the region where the light sensor of the external light illuminance detection circuit 40 is formed are displayed on the display panel 30. Is integrated with the λ / 4 retardation film 33 and the polarizing plate 34 provided in the region covering the film, and this is extended. The relationship between the optical axes of the λ / 4 retardation plate 33 and the polarizing plate 34 will be described later.

  Note that the present invention is not limited to such a configuration, and the λ / 4 phase difference plate 33 and the polarizing plate 34 provided in the upper part of the region where the optical sensor of the external light illuminance detection circuit 40 is formed are provided on the display panel 30. The λ / 4 retardation plate 33 and the polarizing plate 34 provided in the area covering the display area may be provided separately from each other.

  Next, the configuration shown in FIG. 3 shows a configuration in the case where the organic EL element in the display pixel PIX formed on one surface of the display substrate 31 has the above bottom emission structure. In this case, the light emitted by the organic EL element is emitted through the display substrate 31 in the direction indicated by the arrow above the drawing. Then, an optical sensor of the external light illuminance detection circuit 40 is formed in a region corresponding to the external light capturing window 16 of the front side case 11 on one surface of the display substrate 31.

  A λ / 4 phase difference plate 33 and a polarizing plate 34 are provided at least in a region corresponding to the display region on the other surface side facing the one surface side of the display substrate 31 of the display panel 30. The upper surface of the polarizing plate 34 is supported by the front surface side case 11 with the other surface side of the sealing substrate 32 of the display panel 30 facing the one surface side of the display substrate 31 in contact with and supported by the inner surface of the back surface case 12. The display panel 30 is housed in the display panel housing section 14 by being restrained by the inner surface of the outer periphery of the display window 15. Here, the λ / 4 phase difference plate 33 and the polarizing plate 34 are provided in a region that covers the display region of the display panel 30, and an optical sensor of the external light illuminance detection circuit 40 is formed above the display substrate 31. It is also provided in the upper part of the area. For example, as shown in FIGS. 1 and 3, the λ / 4 phase difference plate 33 and the polarizing plate 34 provided in the upper part of the region where the optical sensor is formed are provided in a region covering the display region of the display panel 30. The λ / 4 retardation plate 33 and the polarizing plate 34 are extended.

  Note that the λ / 4 phase difference plate 33 and the polarizing plate 34 provided in the upper part of the region where the optical sensor of the external light illuminance detection circuit 40 is formed are provided in the region covering the display region of the display panel 30. The plate 33 and the polarizing plate 34 may be provided separately from each other.

  Next, an example of the configuration of the active display pixel PIX formed on the display substrate 31 will be described. FIG. 4 is an equivalent circuit illustrating an example of the configuration of the display pixel PIX. The display pixel PIX includes an organic EL element OEL, and a pixel driving circuit including a selection TFT (TFT1), a driving TFT (TFT2), and a holding capacitor Cs. In this pixel driving circuit, the gate electrode of the selection TFT 1 is connected to the scanning line SL, the drain electrode of the selection TFT 1 is connected to the data line DL, the source electrode and the gate electrode of the driving TFT 2 are connected, The holding capacitor Cs is connected to the gate electrode of the driving TFT 2, the cathode of the organic EL element OEL is connected to the drain electrode of the driving TFT 2, and the anode of the organic EL element OEL is connected to the power supply voltage Vdd. Then, the selection signal is applied to the scanning line SL to be high level, the selection TFT 1 is turned on, the display data Vdata is applied to the data line DL, and the charge corresponding to the display data Vdata is applied to the holding capacitor Cs. Through the organic EL element OEL, a current corresponding to the electric charge accumulated in the holding capacitor Cs flows in the current path between the drain and source electrodes of the driving TFT 2, and the organic EL element OEL becomes display data. It is configured to emit light with a corresponding luminance.

  Next, an example of the configuration of the external light illuminance detection circuit 40 will be described. FIG. 5 is an equivalent circuit showing an example of the circuit configuration of the external light illuminance detection circuit 40 and a timing chart for explaining the operation thereof. As shown in FIG. 5A, the ambient light illuminance detection circuit 40 includes, for example, a light sensor TFT (light sensor) 41 configured to receive ambient light in the gate semiconductor layer portion, a charge TFT 42, and a readout TFT 43. And a photosensor circuit 45 including a dark current holding capacitor 44. Here, each TFT constituting the photosensor circuit 45 is formed by the same process as the TFT provided in the pixel driving circuit of the display pixel PIX shown in FIG. 4, for example, and at the same time as the formation of the TFT of the pixel driving circuit. Can be formed. In the optical sensor circuit 45, the selection signal Vsel is applied to the gate electrode of the charging TFT 42, the refresh signal Rfsh is applied to the gate electrode of the optical sensor TFT 41, the power supply voltage Vdd is supplied to the drain electrode of the charging TFT 42, and the drain of the readout TFT 43 The electrode is connected to the output terminal Sout.

  Then, as shown in FIG. 5B, the selection signal Vsel is set to the high level, the refresh signal Rfsh is set to the high level at the beginning of the selection period in which the charging TFT 42 is turned on, and the photosensor TFT 41 is turned on. As a result, the charge accumulated in the dark current holding capacitor 44 is discharged. Next, in a selection period after the refresh signal Rfsh becomes a low level, the photosensor TFT 41 is turned off, the electric charge corresponding to the power supply voltage Vdd is accumulated in the dark current holding capacitor 44, and the dark current holding capacitor 44 is charged. The readout TFT 43 is turned on according to the charged electric charge, and the current Is is observed. In this state, when external light is irradiated to the semiconductor layer portion of the photosensor TFT 41, a channel is formed between the drain and source of the photosensor TFT 41 in accordance with the amount of emitted light, and a current flows out. Since the accumulated electric charge begins to be discharged, the gate voltage of the read TFT 43 is lowered, so that the drain current Is of the read TFT 43 is reduced. The decrease amount ΔIs of the current Is during the preset readout period A, which is observed at the output terminal Sout, is a current according to the external light illuminance.

Next, FIG. 6 shows a cross-sectional view of an example of the configuration of the optical sensor TFT 41 in the external light illuminance detection circuit 40. Here, FIG. 6A shows a configuration when the organic EL element of the display pixel PIX has a top emission structure, which corresponds to FIG. 2, and FIG. 6B shows the organic EL of the display pixel PIX. FIG. 3 shows a configuration when the element has a bottom emission structure, and corresponds to FIG. 3. The optical sensor TFT 41 has, for example, an inverted staggered field effect transistor structure, and includes a gate electrode 51 made of an aluminum-based metal or the like provided on one surface of the display substrate 31, and the gate electrode 51. A gate insulating film 52 made of, for example, silicon nitride provided on one surface of the display substrate 31, and a semiconductor thin film made of, for example, intrinsic amorphous silicon, provided at predetermined positions on the upper surface of the gate insulating film 52 on the gate electrode 51. 53, a channel protective film 54 made of, for example, silicon nitride, provided in the center of the upper surface of the semiconductor thin film 53, and both, for example, n-type provided on both sides of the upper surface of the channel protective film 54 and on the upper surface of the semiconductor thin film 53 Ohmic contact layers 55 and 56 made of amorphous silicon, and one ohmic contact The source electrode 57 made of, for example, an aluminum-based metal and the other ohmic contact layer 56 and the upper surface of the gate insulating film 52 are provided on the upper surface of the gate layer 55 and the upper surface of the gate insulating film 52. And a drain electrode 58 made of a system metal or the like.
An insulating film (overcoat film) 59 made of, for example, silicon nitride is provided on the upper surface of the gate insulating film 52 including the source electrode 57 and the drain electrode 58.

  When the organic EL element of the display pixel PIX has a top emission structure, the polarizing plate 34 and the λ / 4 retardation plate 33 out of the external light incident from the external light capturing window 16 as shown in FIG. The light passing through the light enters the optical sensor TFT 41 from the insulating film 59 side and enters the semiconductor thin film 53 through the channel protective film 54. Further, when the organic EL element of the display pixel PIX has a bottom emission structure, as shown in FIG. 6B, out of the external light incident from the external light capturing window 16, the polarizing plate 34 and the λ / 4 phase difference. The light that has passed through the plate 33 is incident on the other surface side of the display substrate 31, the light that has passed through the display substrate 31 and has passed through the gate electrode 51 is incident on the semiconductor thin film 53 through the gate insulating film 52. Be done

  Next, the relationship between the optical axes of the polarizing plate 34 and the λ / 4 retardation plate 33 provided above the formation region of the optical sensor TFT 41 of the external light illuminance detection circuit 40 will be described. FIG. 7 is a diagram for explaining the relationship between the optical axes of the polarizing plate 34 and the λ / 4 retardation plate 33 provided in the upper part of the formation region of the optical sensor TFT 41 of the external light illuminance detection circuit 40. As shown in FIG. 7A, when the fast axis 33a of the λ / 4 phase difference plate 33 is the X direction and the slow axis 33b is the Y direction, the polarization axis (transmission axis) 34a of the polarizing plate 34 is With respect to the slow axis 33b of the λ / 4 retardation plate 33, it is set to be approximately 45 ° clockwise (or approximately 135 ° counterclockwise).

  Now, when external light is incident on the polarizing plate 34 through the external light capturing window 16 of the front side case 11, as indicated by an arrow A in FIG. 7B, along the polarizing axis 34 a of the polarizing plate 34. The linearly polarized light of the polarization component is transmitted through the polarizing plate 34. The transmitted linearly polarized light becomes circularly polarized light when transmitted through the λ / 4 phase difference plate 33. This circularly polarized light passes through the channel protective film 54 between the source electrode 57 and the drain electrode 58 of the photosensor TFT 41 shown in FIG. 6 and is incident on the semiconductor thin film 53, and the illuminance of external light corresponding to the amount of incident light is increased. Detected.

  On the other hand, a part of the circularly polarized light transmitted through the λ / 4 retardation plate 33 is reflected on the surfaces of the gate electrode 51, the source electrode 57, the drain electrode 58, and the like made of an aluminum-based metal of the optical sensor TFT 41 shown in FIG. The This reflected light is transmitted again through the λ / 4 retardation plate 33 and becomes linearly polarized light. This linearly polarized light is in the direction indicated by the arrow B in FIG. This linearly polarized light is linearly polarized light having a polarization component orthogonal to the polarization axis 34 a of the polarizing plate 34 and is absorbed by the polarizing plate 34. Therefore, even if external light is reflected by the optical sensor TFT 41, the reflected light can be prevented from being emitted to the surface side, and discoloration of the appearance due to such emitted light can be prevented. The angle formed between the slow axis of the λ / 4 phase difference plate 33 and the polarization axis of the polarizing plate 34 is 45 ° clockwise (or 135 ° counterclockwise). The rate at which the reflected light reflected by the surface of the electrode 58 or the like is absorbed by the polarizing plate 34 is maximized, which is ideal. Even if the angle is deviated by, for example, about ± 1 °, substantially the same effect can be obtained. Therefore, the angle formed between the slow axis of the λ / 4 retardation plate 33 and the polarization axis of the polarizing plate 34 is 44 ° to 46 ° (= 45 ° ± 1 °) in the clockwise direction (or 134 ° in the counterclockwise direction). ˜136 ° (= 135 ° ± 1 °).

  Further, the organic EL element in the display pixel PIX usually has a reflective electrode made of metal that is configured to reflect and emit light emitted isotropically from the organic EL layer in one direction. Although the external light is reflected by the reflective electrode and emitted to the surface side, the display quality may be deteriorated. However, the polarizing plate 34 and the λ / 4 phase difference plate 33 form the display area of the display panel 30. By being provided also in the area | region to cover, the fall of display quality can be suppressed so that the reflected light by a reflective electrode may not be radiate | emitted by the surface side.

  Note that, as described above, the polarizing plate and the λ / 4 phase difference plate provided in the upper part of the formation region of the photosensor TFT 41 of the external light illuminance detection circuit 40 are combined with the polarizing plate 34 and λ / 4 that cover the display region of the display panel 30. An extension of the retardation plate may be used, or the polarizing plate 34 and the λ / 4 retardation plate 33 that cover the display area of the display panel 30 may be separated. At this time, the polarization axis, the fast axis, and the slow axis of the polarizing plate and the λ / 4 phase difference plate that are provided above the formation area of the optical sensor TFT 41 of the external light illuminance detection circuit 40 cover the display area of the display panel 30. The polarization axis, the fast axis, and the slow axis of the polarizing plate and the λ / 4 retardation plate may be the same or different.

<Modification>
Next, a modified example related to the display device according to the present embodiment will be described.
FIG. 8 is a cross-sectional view illustrating a configuration of a first modification example of the present embodiment. Here, FIG. 8A shows a configuration in the case where the organic EL element has a top emission structure, which corresponds to FIG. 2, and FIG. 8B shows a structure in which the organic EL element has a bottom emission structure. FIG. 3 shows a configuration corresponding to FIG. In this modification, a minute lens 50 (such as a microlens or a lenticular lens) for condensing is provided directly above the light sensor TFT 41 on the light incident side, and the amount of light to be increased is detected. It is intended to increase the sensitivity of.

  When the organic EL element has a top emission structure, as shown in FIG. 6A, the light incident from the external light capturing window 16 and passed through the polarizing plate 34 and the λ / 4 retardation plate 33 is Since the lens 50 is provided on the upper surface of the insulating film 59 corresponding to the gate electrode 51, as shown in FIG. By increasing the amount of light incident on the optical sensor TFT 41, the sensitivity of detecting the ambient light illuminance can be increased. When the organic EL element has a bottom emission structure, as shown in FIG. 6B, the light that has entered through the external light capturing window 16 and has passed through the polarizing plate 34 and the λ / 4 retardation plate 33. Is incident on the optical sensor TFT 41 from the other surface side of the display substrate 31, and therefore, as shown in FIG. 8B, by providing a lens 50 on the upper surface of the display substrate 31 corresponding to the gate electrode 51. A relatively wide range of light can be collected by the lens 50 and incident on the optical sensor TFT 41 to increase the sensitivity of detecting ambient light illuminance. However, in FIG. 6B, the polarizing plate 34 and the λ / 4 retardation plate 33 are directly provided on the other surface side of the display substrate 31. However, in this modification, the lens 50 is the display substrate 31. Since it is provided on the other surface side, the polarizing plate 34 and the λ / 4 retardation plate 33 cannot be directly provided on the other surface side of the display substrate 31. Therefore, in this case, for example, as shown in FIG. 8B, a convex portion is provided in the external light capturing window 16 of the surface side case 11, and the polarizing plate 34 and the λ / 4 phase difference plate 33 are provided there. To be provided.

  Next, FIG. 9 is a cross-sectional view showing a configuration of a second modification example of the present embodiment. This corresponds to the case where the organic EL element has a bottom emission structure. When the organic EL element has a bottom emission structure, as shown in FIG. 6B, the light incident from the external light capturing window 16 and passing through the polarizing plate 34 and the λ / 4 phase difference plate 33 is The light enters from the other surface side of the display substrate 31 to the gate electrode 51 side of the photosensor TFT 41. Here, since the gate electrode 51 is usually made of an aluminum-based metal or the like and has a light-shielding property, light that has entered the gate electrode 51 enters the semiconductor thin film 53 via the gate insulating film 52. Thus, the amount of light incident on the semiconductor thin film 53 is reduced as compared with the configuration in the case where the organic EL element has a top emission structure. Therefore, in this modification, the gate electrode 51 is formed of a transparent conductive film made of, for example, ITO. According to this modification, since the gate electrode 51 has light transmittance, light incident on the gate electrode 51 side of the photosensor TFT 41 from the other surface side of the display substrate 31 is gate electrode 51 and gate insulating film. The amount of light passing through 52 and entering the semiconductor thin film 53 and entering the semiconductor thin film 53 can be increased, and the sensitivity of detecting the illuminance of outside light can be increased. Since ITO has a higher electrical resistance than aluminum-based metal, when it is used for the gate electrode, the operation speed of the transistor is slower than when aluminum-based metal is used for the gate electrode. Since it does not require such a high-speed operation, it can be applied without any problem.

  Further, FIG. 10 is a cross-sectional view showing a configuration of a third modification of the present embodiment. This modification also corresponds to the case where the organic EL element has a bottom emission structure. As described above, since the gate electrode 51 normally has a light shielding property, the amount of light incident on the semiconductor thin film 53 is relatively small in the configuration where the organic EL element has a bottom emission structure. Therefore, in this modification, as shown in FIG. 10A, the optical sensor TFT 41 has a structure without the gate electrode 51. According to this modification, since the gate electrode 51 is not provided, the light incident on the other surface side of the display substrate 31 passes through the gate insulating film 52 of the photosensor TFT 41 and enters the semiconductor thin film 53. The amount of light incident on the semiconductor thin film 53 can be increased, and the sensitivity of detecting ambient light illuminance can be increased. However, in this configuration, the refresh signal Rfsh cannot be applied to the gate electrode of the photosensor TFT 41 to discharge the charge accumulated in the dark current holding capacitor 44. Therefore, as shown in FIG. The refresh TFT 46 connected between the source and drain electrodes of the photosensor TFT 41 is provided, and the refresh signal Rfsh is applied to the gate electrode of the refresh TFT 46 to discharge the charge accumulated in the dark current holding capacitor 44. Can be. Furthermore, as shown in FIG. 10C, the condensing lens 50 is provided on the upper surface of the other surface side of the display substrate 31 in the first modification, in the configuration of the third modification. It is good also as a structure which combined the structure. In this case, the light condensed by the lens 50 passes through the gate insulating film 52 of the optical sensor TFT 41 and enters the semiconductor thin film 53, so that the amount of light incident on the semiconductor thin film 53 can be further increased. The sensitivity of detection can be further increased.

  In the above embodiment, a display device using an organic EL element as a light emitting element has been described. However, the display device according to the present invention is not limited to this, and other self-luminous light emitting elements such as a light emitting diode, for example. Even so, it can be applied satisfactorily.

  In addition, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention in the implementation stage. Further, the functions executed in the above-described embodiments may be combined as appropriate as possible. The above-described embodiment includes various stages, and various inventions can be extracted by an appropriate combination according to a plurality of disclosed structural requirements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, if the effect is obtained, a configuration from which the constituent requirements are deleted can be extracted as an invention.

The top view which shows the principal part of the display apparatus as one Embodiment of this invention. FIG. 2 is a first structural example of a cross-sectional view taken along line II-II in FIG. 1. The 2nd structural example of sectional drawing which follows the II-II line | wire of FIG. 6 is an equivalent circuit illustrating an example of a configuration of a display pixel. The equivalent circuit which shows an example of a structure of an external light illumination intensity detection sensor, and the timing chart for demonstrating the operation | movement. Sectional drawing of an example of a structure of the part of optical sensor TFT in an optical sensor. The figure for demonstrating the relationship of each optical axis of the polarizing plate provided in the upper part of the formation area of an optical sensor, and (lambda) / 4 phase difference plate. Sectional drawing which shows the structure of the 1st modification in this embodiment. Sectional drawing which shows the structure of the 2nd modification in this embodiment. Sectional drawing which shows the structure of the 3rd modification in this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display apparatus 11 Front side case 12 Back side case 14 Display panel storage part 15 Display window 16 External light taking-in window 30 Display panel 31 Display substrate 32 Sealing substrate 33 (lambda) / 4 phase difference plate 34 Polarizing plate PIX Display pixel 40 External light illumination intensity Detection circuit 41 Optical sensor TFT
50 Lens 51 Gate electrode

Claims (10)

A display substrate having a display region in which a plurality of display pixels each having a light emitting element are formed on one surface;
An external light illuminance detection circuit having an optical sensor for detecting external light illuminance provided in a region different from the display region on the one surface of the display substrate;
A light-shielding λ / 4 retardation plate provided on a side where external light received by the optical sensor is incident on an area of the display substrate where the optical sensor of the external light illuminance detection circuit is provided; A light-shielding polarizing plate provided on the surface side of the λ / 4 retardation plate for use,
A display device, wherein an angle formed by a slow axis of the light-shielding λ / 4 retardation plate and a polarization axis of the light-shielding polarizing plate is 45 ° ± 1 ° or 135 ° ± 1 °. Furthermore, the display λ / 4 retardation plate provided on the light emission surface side of the display region, and a display polarizing plate provided on the surface side of the display λ / 4 retardation plate,
The light blocking λ / 4 retardation plate and the display λ / 4 retardation plate are integrally formed, and the light blocking polarizing plate and the display polarizing plate are formed integrally. The display device according to claim 1. Furthermore, the display λ / 4 retardation plate provided on the light emission surface side of the display region, and a display polarizing plate provided on the surface side of the display λ / 4 retardation plate,
2. The light shielding λ / 4 phase difference plate and the light shielding polarizing plate, and the display λ / 4 phase difference plate and the display polarizing plate are separately provided. The display device described.   Furthermore, it has at least 1 condensing lens provided in the side in which the external light which this optical sensor receives with respect to the area | region in which the said optical sensor in the said display board was provided. Item 4. The display device according to Item 1.   The display device according to claim 1, further comprising: a sealing substrate that covers and seals the display region on the one surface of the display substrate. Light emitted from each light emitting element in the display region is emitted in a direction from the one surface of the display substrate to the outer surface of the sealing substrate through the sealing substrate.
6. The light shielding λ / 4 phase difference plate and the light shielding polarizing plate are provided on the one surface of the display substrate above an area where the optical sensor is provided. The display device described. The light emitted from each light emitting element in the display region is emitted from the one surface of the display substrate through the display substrate, from the other surface side facing the one surface of the display substrate,
The display device according to claim 1, wherein the light blocking λ / 4 retardation plate and the light blocking polarizing plate are provided on the other surface of the display substrate.   8. The display device according to claim 7, wherein the photosensor has an inverted staggered thin film transistor structure, the photosensor has a gate electrode, and the gate electrode is made of a transparent conductive film.   The display device according to claim 7, wherein the photosensor has a thin film transistor structure, and the photosensor does not have a gate electrode.   And a case in which at least the display substrate is accommodated therein, a display window is provided in a portion corresponding to the display area of the display substrate, and an external light capturing window is provided in a portion corresponding to the photosensor. The display device according to claim 1.

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