Display device

Abstract

To provide a display device capable of enhancing the image quality in a bright environment.SOLUTION: The display device comprises: pixels including light emitters 36 and quantum dot layers 44R, 44G configured to convert the wavelength of light emitted by the light emitters 36; and a light reducing film 41 formed on the side opposite to the light emitters 36 with respect to the quantum dot layers 44R, 44G, and configured to reduce external light incident on the quantum dot layers 44R, 44G. In contrast, neither the color filter nor the quantum dot layers are formed in blue sub-pixels 21B.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a display device. [Background technology]

[0002] Patent Document 1 describes the development of a display device that uses a blue organic light-emitting diode (OLED) as a light-emitting element and a quantum dot layer as a light conversion layer that converts the wavelength of light emitted from the OLED (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Korean Patent Publication No. 10-2017-0096583 Summary of the Invention [Problem to be solved by the invention]

[0004] When a quantum dot layer is used as the light conversion layer, when external light is incident on the quantum dot layer and hits the quantum dots in the quantum dot layer, the quantum dots are excited and emit light. The light from the emitted quantum dots has a different direction and polarization from the incident external light. Therefore, even if an anti-reflection film is formed on the display surface, it is difficult to prevent the light emitted from the quantum dots that emit light due to external light from emitting from the display surface. This results in a deterioration of image quality, especially in a bright environment.

[0005] In view of the above-mentioned problems, an object of the present invention is to provide a display device capable of improving image quality in a bright environment. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a display device comprising: a pixel including a light-emitting element and a quantum dot layer that converts the wavelength of light emitted from the light-emitting element; and a light-reducing film formed on the opposite side of the quantum dot layer from the light-emitting element and that reduces external light incident on the quantum dot layer. Effect of the Invention

[0007] According to the present invention, image quality can be improved in a bright environment. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a display device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing an example of an arrangement of pixels and sub-pixels on a panel of the display device according to the first embodiment of the present invention. [Diagram 3] FIG. 3 is a circuit diagram showing a schematic configuration of a sub-pixel of the display device according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view showing a schematic configuration of a pixel of the display device according to the first embodiment of the present invention. [Diagram 5] FIG. 5 is a schematic diagram showing emission of a pixel of the display device according to the first embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view showing a schematic configuration of a pixel of a display device according to a modified example of the first embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view showing a schematic configuration of a pixel of a display device according to a second embodiment of the present invention. [Figure 8] FIG. 8 is a cross-sectional view showing a schematic configuration of a pixel of a display device according to a modified example of the second embodiment of the present invention. [Figure 9] FIG. 9 is a cross-sectional view showing a schematic configuration of a pixel of a display device according to a third embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view showing a schematic configuration of a pixel of a display device according to a modified example of the third embodiment of the present invention. [Figure 11]FIG. 11 is a cross-sectional view showing a schematic configuration of a pixel of a display device according to a fourth embodiment of the present invention. [Figure 12] FIG. 12 is a cross-sectional view showing a schematic configuration of a pixel of a display device according to a modified example of the fourth embodiment of the present invention. [Figure 13] FIG. 13 is a cross-sectional view showing a schematic configuration of a pixel of a display device according to a fifth embodiment of the present invention. [Figure 14] FIG. 14 is a cross-sectional view showing a schematic configuration of a pixel of a display device according to a modified example of the fifth embodiment of the present invention. [Figure 15] FIG. 15 is a cross-sectional view showing a schematic configuration of a pixel of a display device according to a sixth embodiment of the present invention. [Figure 16] FIG. 16 is a cross-sectional view showing a schematic configuration of a pixel of a display device according to a modified example of the sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [First embodiment] A display device according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG.

[0010] First, a schematic configuration of a display device according to the present embodiment will be described with reference to FIGS. 1 to 3. FIG. Fig. 1 is a block diagram showing a schematic configuration of a display device according to the present embodiment. Fig. 2 is a diagram showing an example of an arrangement of pixels and sub-pixels in a panel of the display device according to the present embodiment. Fig. 3 is a circuit diagram showing a schematic configuration of a sub-pixel of the display device according to the present embodiment.

[0011] The display device according to the present embodiment is a device that uses an organic light-emitting diode (OLED) as a light-emitting element in a pixel and displays an image based on input RGB data. The use of the display device according to the present embodiment may be, for example, an image output device of a computer, a television receiver, a smartphone, a game machine, etc., but is not particularly limited thereto.

[0012] 1, the display device includes a timing controller (TCON) 1, a panel 2, a plurality of source drive ICs (SDIC) 3, and a plurality of gate drive ICs (GDIC) 4. The panel 2 includes a plurality of pixels arranged in a matrix, and functions as a display unit that displays an image.

[0013] The timing controller 1 is communicatively connected to a plurality of source drive ICs 3 and a plurality of gate drive ICs 4. The timing controller 1 controls the operation timing of the plurality of source drive ICs 3 and the plurality of gate drive ICs 4 based on timing signals (vertical synchronization signal, horizontal synchronization signal, data enable signal, etc.) input from an external system.

[0014] As described later, a pixel in the panel 2 has sub-pixels of red (R), green (G), and blue (B) colors. The timing controller 1 generates RGB data indicating the luminance of each sub-pixel of the panel 2 based on RGB data, which is an input signal input from an external system, and outputs the RGB data as output signals to a plurality of source drive ICs 3. Note that the numbers of source drive ICs 3 and gate drive ICs 4 are not limited to those shown in the figure.

[0015] Each of the multiple source drive ICs 3 supplies a voltage (video signal) for driving multiple pixels in the panel 2 via multiple data lines in response to control of the timing controller 1. Each of the multiple gate drive ICs 4 supplies a scan signal to multiple pixels in the panel 2 via multiple gate lines in response to control of the timing controller 1. In this way, the timing controller 1 functions as a display control device that controls the operation of the entire display device.

[0016] 2(a) and 2(b) are respectively arrangement diagrams of a pixel 20 and subpixels 21R, 21G, and 21B in a panel 2. The panel 2 includes a plurality of pixels 20 arranged in a plurality of rows and a plurality of columns. Each of the plurality of pixels 20 includes a subpixel 21R that emits red light, a subpixel 21G that emits green light, and a subpixel 21B that emits blue light. In the following description, the subpixels 21R, 21G, and 21B will be simply referred to as "subpixel 21" when there is no need to distinguish between the colors.

[0017] The sub-pixels 21R, 21G, and 21B are arranged side by side in a certain direction in the pixel 20, as shown in FIG.

[0018] The luminance of the sub-pixels 21R, 21G, and 21B is controlled according to the voltage output from the source drive IC 3. The sub-pixels 21R, 21G, and 21B emit light at a predetermined luminance ratio, allowing the pixel 20 to display various colors through additive color mixing.

[0019] In this way, the display device of this embodiment includes the cyan subpixel 21C as the fourth subpixel, and has a pixel configuration compatible with RGBC four-color display.

[0020] In this specification, one of red and green may be referred to as a first color, blue as a second color, and the other of red and green as a third color. In addition, in this specification, one of the red and green subpixels may be referred to as a first subpixel, the blue subpixel as a second subpixel, and the other of the red and green subpixels as a third subpixel.

[0021] In this embodiment, quantum dot layers of each color are appropriately formed in the subpixels as light conversion layers. The quantum dot layers of each color function as wavelength conversion layers that convert the wavelength of light emitted from the OLED and incident thereon to emit light of each color. Specifically, for example, the red quantum dot layer converts blue light emitted from the blue OLED to emit red light. The green quantum dot layer converts blue light emitted from the blue OLED to emit green light. The quantum dot layer is composed of a layer of resin or the like in which quantum dots made of semiconductor materials or the like having particle sizes, materials, or the like corresponding to the output wavelength are dispersed.

[0022] Fig. 3 shows a schematic configuration of a subpixel 21. Fig. 3 shows a subpixel 21 included in one of the multiple pixels 20, one source drive IC3 connected to the subpixel 21, and one gate drive IC4 connected to the subpixel 21.

[0023] The sub-pixel 21 includes a scan transistor M1, a drive transistor M2, and a diode D. The diode D is a light-emitting element of the display device, which is an OLED. The scan transistor M1 and the drive transistor M2 are, for example, thin film transistors (TFTs). In this embodiment, the scan transistor M1 and the drive transistor M2 are n-channel types. However, the scan transistor M1 and the drive transistor M2 may be p-channel types. Note that if the drive transistor M2 is a p-channel type, the circuit configuration of the sub-pixel 21 may be different from that shown in FIG. 3.

[0024] The cathode of the diode D is connected to a potential line that supplies a potential VSS. The anode of the diode D is connected to a source of the drive transistor M2. The drain of the drive transistor M2 is connected to a potential line that supplies a potential VDD. The gate of the drive transistor M2 is connected to the source of the scan transistor M1.

[0025] A data line DL is connected to the drain of the scan transistor M1. The source driver IC3 supplies a video signal to the drain of the scan transistor M1 via the data line DL. A gate line GL is connected to the gate of the scan transistor M1. The gate driver IC4 supplies a control signal to the gate of the scan transistor M1 via the gate line GL. The scan transistor M1 is controlled to be on or off depending on the level of the control signal input to the gate.

[0026] The current flowing between the drain and source of the drive transistor M2 is controlled based on a voltage (video signal) input to the gate of the drive transistor M2 from the source drive IC3 via the data line DL and the scan transistor M1. The current flowing between the drain and source of the drive transistor M2 is supplied to the diode D, and the diode D emits light with a brightness according to the current. In this way, the diode D emits light with a brightness according to the video signal input to the sub-pixel 21.

[0027] Next, the pixel 20 of the display device according to the present embodiment will be further described with reference to Fig. 4 and Fig. 5. Fig. 4 is a cross-sectional view showing a schematic configuration of the pixel 20 of the display device according to the present embodiment. Fig. 5 is a schematic diagram showing light emission of the pixel 20 of the display device according to the present embodiment.

[0028] As shown in FIG. 4, each pixel 20 in the panel 2 has a red sub-pixel 21R, a green sub-pixel 21G, and a blue sub-pixel 21B.

[0029] The panel 2 has an element substrate 100 and a color filter substrate 200. The color filter substrate 200 is disposed so as to face the element formation surface of the element substrate 100. The display device according to this embodiment is of a top emission type in which light is emitted from the element formation surface side of the glass substrate 30 of the element substrate 100. That is, in the display device according to this embodiment, the element formation surface side of the glass substrate 30 of the element substrate 100 is the display surface side.

[0030] The element substrate 100 has a glass substrate 30 which is a transparent substrate, and a blue OLED 32 which is a light emitting element that emits blue light. In the following, the case where the glass substrate 30 and glass substrates 40, 50, and 60 described below are used as substrates of the panel 2 will be described as an example, but instead of these glass substrates, various transparent substrates such as a flexible transparent resin substrate can be used.

[0031] In each pixel 20, three anode electrodes 34 made of metal electrodes are formed on the element formation surface of the glass substrate 30 so as to correspond to the sub-pixels 21R, 21G, and 21B. The anode electrodes 34 are configured as reflective electrodes having sufficient reflectivity and also functioning as reflective layers. On each anode electrode 34, a blue organic light-emitting layer 36 made of an organic light-emitting material that emits blue light is formed. On each blue organic light-emitting layer 36, a common cathode electrode 38 made of a transparent electrode is formed.

[0032] In this manner, an OLED 32 having an anode electrode 34, a blue organic light-emitting layer 36, and a cathode electrode 38 is formed for each of the sub-pixels 21R, 21G, and 21B in each pixel 20. A sealing film (not shown) or the like is formed on the entire surface of the glass substrate 30 on which the cathode electrode 38 is formed.

[0033] On the other hand, the color filter substrate 200 has a glass substrate 40 which is a transparent substrate, color filters 42R, 42G, quantum dot layers 44R, 44G, a semi-transmissive film 46, and an anti-reflection film 48. The anti-reflection film 48 has a quarter-wave plate 481 and a polarizing plate 482.

[0034] A red color filter 42R is formed on the surface of the glass substrate 40 facing the element substrate 100 so as to face the OLED 32 of the red sub-pixel 21R. The color filter 42R is formed on the glass substrate 40 via a semi-transmissive film 41. The semi-transmissive film 41 is formed with a predetermined film thickness so as to transmit visible light with a predetermined transmittance. The semi-transmissive film 41 is not particularly limited, but is, for example, a metal film such as an aluminum film. A red quantum dot layer 44R is formed on the surface of the color filter 42R facing the element substrate 100. The red quantum dot layer 44R functions as a light conversion layer that converts the wavelength of light, and converts the wavelength of blue light emitted from the OLED 32 and incident thereon to emit red light. The light emitted from the quantum dot layer 44R includes unconverted blue light as well as red light.

[0035] In this way, a red sub-pixel 21R is formed, which has a blue OLED 32, a red quantum dot layer 44R, and a red color filter 42R. In the sub-pixel 21R having the quantum dot layer 44R, a semi-transparent film 41 is formed between the color filter 42R and the glass substrate 40 on the display surface side of the panel 2 with respect to the quantum dot layer 44R, which is the external light intrusion side with respect to the quantum dot layer 44R. In other words, the semi-transparent film 41 is formed on the opposite side of the quantum dot layer 44R to the OLED 32 and on the opposite side of the color filter 42R to the quantum dot layer 44R.

[0036] A green color filter 42G is formed on the surface of the glass substrate 40 facing the element substrate 100 so as to face the OLED 32 of the green subpixel 21G. The color filter 42G is formed on the glass substrate 40 via a semi-transmissive film 41, similar to the color filter 42R. A green quantum dot layer 44G is formed on the surface of the color filter 42G facing the element substrate 100. The green quantum dot layer 44G functions as a light conversion layer that converts the wavelength of light, and converts the wavelength of the blue light emitted from the OLED 32 and incident thereon to emit green light. The light emitted from the quantum dot layer 44G contains unconverted blue light as well as green light.

[0037] In this way, a green subpixel 21G is formed, which has a blue OLED 32, a green quantum dot layer 44G, and a green color filter 42G. In the subpixel 21G having the quantum dot layer 44G, a semi-transparent film 41 is formed between the color filter 42G and the glass substrate 40 on the display surface side of the panel 2 with respect to the quantum dot layer 44R, which is the external light intrusion side with respect to the quantum dot layer 44G. In other words, the semi-transparent film 41 is formed on the opposite side of the quantum dot layer 44G to the OLED 32, and on the opposite side of the color filter 42G to the quantum dot layer 44R.

[0038] On the other hand, on the surface of the glass substrate 40 facing the element substrate 100, neither a color filter nor a quantum dot layer is formed so as to face the OLED 32 of the blue subpixel 21B. Therefore, the blue subpixel 21B has a blue OLED 32, but does not have a blue color filter or other color filters or a quantum dot layer. In other words, the subpixel 21B emits blue light without passing through a blue color filter or other color filters.

[0039] In addition, a semi-transparent film 41 may be formed on the glass substrate 40 in the blue sub-pixel 21B, which does not have a quantum dot layer. However, from the viewpoint of ensuring brightness, it is preferable that the semi-transparent film 41 is not formed in the sub-pixel 21B.

[0040] A sealing film (not shown) or the like is formed on the entire surface of the glass substrate 40 on which the color filters 42R, 42G and the quantum dot layers 44R, 44G are formed.

[0041] In this manner, the pixel 20 having the sub-pixels 21R, 21G, and 21B is formed.

[0042] Fig. 5 shows a schematic diagram of the emission of each of the sub-pixels 21R, 21G, and 21B. In Fig. 5, arrows Lr indicate red light, arrows Lg indicate green light, and arrows Lb indicate blue light, and the number of arrows indicates the amount of light. For convenience, the arrangement of each component shown in Fig. 5 does not match the arrangement of each component shown in Fig. 4.

[0043] In the red subpixel 21R, as shown in FIG. 5, first, blue light Lb is emitted from the OLED 32. Next, the blue light Lb is converted into red light Lr by the red quantum dot layer 44R and emitted from the quantum dot layer 44R. At this time, since the conversion rate of the quantum dot layer 44R is not 100%, unconverted blue light Lb is emitted from the quantum dot layer 44R together with the red light Lr. Also, a part of the blue light Lb is inactivated or absorbed in the quantum dot layer 44R. Next, the red light Lr emitted from the quantum dot layer 44R passes through the red color filter 42R and is emitted from the display surface of the panel 2. At this time, the blue light Lb emitted from the quantum dot layer 44R is absorbed by the color filter 42R.

[0044] In the green subpixel 21G, as shown in FIG. 5, first, blue light Lb is emitted from the OLED 32. Next, the blue light Lb is converted into green light Lg by the green quantum dot layer 44G and emitted from the quantum dot layer 44G. At this time, since the conversion rate of the quantum dot layer 44G is not 100%, unconverted blue light Lb is emitted from the quantum dot layer 44G together with the green light Lg. Also, a part of the blue light Lb is inactivated or absorbed in the quantum dot layer 44G. Next, the green light Lg emitted from the quantum dot layer 44G passes through the green color filter 42G and is emitted from the display surface of the panel 2. At this time, the blue light Lb emitted from the quantum dot layer 44G is absorbed by the color filter 42G.

[0045] 5, in the blue subpixel 21B, blue light Lb is first emitted from the OLED 32. Then, the blue light Lb is emitted directly from the display surface of the panel 2 without passing through a quantum dot layer or a color filter.

[0046] In this embodiment, a semi-transparent film 41 is formed between the color filters 42R, 42G and the glass substrate 40 on the display surface side of the panel 2 relative to the quantum dot layers 44R, 44G, which is the entrance side of external light relative to the quantum dot layers 44R, 44G. The semi-transparent film 41 functions as a light reducing film that reduces external light incident on the quantum dot layers 44R, 44G. That is, a part of the external light that enters from the display surface side of the panel 2 is reflected by the semi-transparent film 41. Due to the absorption of external light by the semi-transparent film 41, the external light incident on the quantum dot layers 44R, 44G can be reduced, and the excitation of the quantum dots due to the external light can be reduced, thereby reducing the emission of the quantum dot layers 44R, 44G. This can improve the image quality in a bright environment, specifically, the display contrast can be improved. The external light reflected by the semi-transparent film 41 is prevented from being emitted from the display surface of the panel 2 by the anti-reflection film 48.

[0047] Furthermore, even if the light originally emitted from the quantum dot layers 44R, 44G by the sub-pixels 41R, 41G is reflected by the semi-transmissive film 41, it is reflected again by the anode electrode 34, which serves as a reflective electrode, and can be emitted from the display surface of the panel 2. This makes it possible to suppress a decrease in luminance caused by the semi-transmissive film 41.

[0048] In this way, according to this embodiment, it is possible to improve image quality in a bright environment.

[0049] (Modification) A display device according to a modification of this embodiment will be described with reference to Fig. 6. Fig. 6 is a cross-sectional view showing a schematic configuration of a pixel of the display device according to the modification of this embodiment.

[0050] In the present embodiment, as shown in FIG. 4, a semi-transmissive film 41 is formed between the color filters 42R and 42G and the glass substrate 40, but the present invention is not limited to this.

[0051] As shown in Fig. 6, the semi-transparent film 41 may be formed between the color filter 42R and the quantum dot layer 44R, and between the color filter 42G and the quantum dot layer 44G. In the configuration shown in Fig. 6, the semi-transparent film 41 is also formed on the display surface side of the panel 2 with respect to the quantum dot layers 44R and 44G, which is the entrance side of external light with respect to the quantum dot layers 44R and 44G. Therefore, in the case shown in Fig. 6, as in the case shown in Fig. 4, the image quality can be improved in a bright environment.

[0052] [Second embodiment] A display device according to a second embodiment of the present invention will be described with reference to Fig. 7. Fig. 7 is a schematic diagram showing a schematic configuration of a pixel of the display device according to this embodiment. Note that components similar to those of the display device according to the first embodiment are given the same reference numerals, and descriptions thereof will be omitted or simplified.

[0053] In the above first embodiment, the OLED is formed on the element substrate 100, and the color filter and the quantum dot layer are formed on the color filter substrate 200, but the present invention is not limited to this. The OLED, the quantum dot layer, and the color filter may be formed on a single glass substrate.

[0054] In this embodiment, a case will be described in which a pixel including three sub-pixels similar to those in the first embodiment is formed on a single glass substrate.

[0055] As shown in FIG. 7, a pixel 20 in a panel 2 has a red sub-pixel 21R, a green sub-pixel 21G, and a blue sub-pixel 21B.

[0056] The panel 2 has a glass substrate 50, but does not have a color filter substrate facing the glass substrate 50. The display device according to this embodiment is of a top emission type in which light is emitted from the element formation surface side of the glass substrate 50. That is, in the display device according to this embodiment, the element formation surface side of the glass substrate 50 is the display surface side.

[0057] Three anode electrodes 34 are formed on an element formation surface of a transparent glass substrate 50 so as to correspond to the sub-pixels 21R, 21G, and 21B. A blue organic light-emitting layer 36 is formed on each anode electrode 34. A common cathode electrode 38 is formed on each blue organic light-emitting layer 36. In this way, in each pixel 20, an OLED 32 is formed for each of the sub-pixels 21R, 21G, and 21B, as in the first embodiment. A sealing film 52 for sealing the OLED 32 is formed on the cathode electrode 38.

[0058] A red quantum dot layer 44R is formed on the sealing film 52 so as to face the OLED 32 of the red sub-pixel 21R. A red color filter 42R is formed on the quantum dot layer 44R. In this way, the red sub-pixel 21R is configured to have the blue OLED 32, the red quantum dot layer 44R, and the red color filter 42R.

[0059] Furthermore, a green quantum dot layer 44G is formed on the sealing film 52 so as to face the OLED 32 of the green subpixel 21G. A green color filter 42G is formed on the quantum dot layer 44G. In this way, the green subpixel 21G is configured to have the blue OLED 32, the green quantum dot layer 44G, and the green color filter 42G.

[0060] A semi-transparent film 41 similar to that of the first embodiment is formed on the color filters 42R, 42G. In this embodiment, the semi-transparent film 41 is formed between the color filters 42R, 42G and a cover film 56 described later on the display surface side of the panel 2 with respect to the quantum dot layers 44R, 44G, which is the external light intrusion side with respect to the quantum dot layers 44R, 44G. That is, the semi-transparent film 41 is formed on the opposite side of the quantum dot layers 44R, 44G to the OLED 32 and on the opposite side of the color filters 42R, 42G to the quantum dot layers 44R, 44G.

[0061] On the other hand, no color filter or quantum dot layer is formed on the sealing film 52 so as to face the OLED 32 of the blue subpixel 21B. Therefore, the blue subpixel 21B has a blue OLED 32, but does not have a blue color filter or other color filters or a quantum dot layer. In other words, the subpixel 21B emits blue light without passing through a blue color filter or other color filters.

[0062] A sealing film 54 that seals the quantum dot layers 44R, 44G, color filters 42R, 42G, and semi-transmissive film 41 is formed on the entire surface of the glass substrate 50 on which the sub-pixels 21R, 21G, 21B, and 21C and the semi-transmissive film 41 are formed. A cover film 56 made of a transparent resin film or the like is formed on the sealing film 54. An anti-reflection film 48 is formed on the cover film 56.

[0063] As in the present embodiment, a pixel including three sub-pixels may be formed on a single glass substrate. In the present embodiment, the image quality can be improved in a bright environment in the same manner as in the first embodiment.

[0064] (Modification) A display device according to a modification of this embodiment will be described with reference to Fig. 8. Fig. 8 is a cross-sectional view showing a schematic configuration of a pixel of the display device according to the modification of this embodiment.

[0065] In the present embodiment, as shown in FIG. 7, the semi-transmissive film 41 is formed between the color filters 42R and 42G and the cover film 56, but the present invention is not limited to this.

[0066] As shown in Fig. 8, the semi-transparent film 41 may be formed between the color filter 42R and the quantum dot layer 44R, and between the color filter 42G and the quantum dot layer 44G. In the configuration shown in Fig. 8, the semi-transparent film 41 is also formed on the display surface side of the panel 2 with respect to the quantum dot layers 44R and 44G, which is the external light intrusion side with respect to the quantum dot layers 44R and 44G. Therefore, in the case shown in Fig. 8, as in the case shown in Fig. 7, the image quality can be improved in a bright environment.

[0067] [Third embodiment] A display device according to a third embodiment of the present invention will be described with reference to Fig. 9. Fig. 9 is a schematic diagram showing a schematic configuration of a pixel of the display device according to this embodiment. Note that components similar to those of the display devices according to the first and second embodiments are given the same reference numerals, and descriptions thereof will be omitted or simplified.

[0068] In the above first and second embodiments, a top emission type pixel configuration has been described, but the present invention is not limited to this, and the pixel may be a bottom emission type.

[0069] In this embodiment, a case will be described in which a pixel including three sub-pixels similar to those in the first embodiment is of a bottom emission type.

[0070] As shown in FIG. 9, a pixel 20 in a panel 2 has a red sub-pixel 21R, a green sub-pixel 21G, and a blue sub-pixel 21B.

[0071] The panel 2 has a glass substrate 60, but does not have a color filter substrate facing the glass substrate 60. The display device according to this embodiment is of a bottom emission type in which light is emitted from the surface of the glass substrate 60 opposite to the element formation surface. That is, in the display device according to this embodiment, the surface of the glass substrate 60 opposite to the element formation surface is the display surface.

[0072] A red color filter 42R and a red quantum dot layer 44R are sequentially laminated on an element formation surface of a transparent glass substrate 60 so as to correspond to the red sub-pixel 21R. The color filter 42R is formed on the glass substrate 60 via a semi-transparent film 41.

[0073] A green color filter 42G and a green quantum dot layer 44G are sequentially laminated on the element formation surface of the glass substrate 60 so as to correspond to the green sub-pixel 21G. The color filter 42G is formed on the glass substrate 60 with a semi-transparent film 41 interposed therebetween.

[0074] In this embodiment, a semi-transparent film 41 is formed between the color filters 42R, 42G and the glass substrate 60 on the display surface side of the panel 2 with respect to the quantum dot layers 44R, 44G, which is the external light intrusion side with respect to the quantum dot layers 44R, 44G. That is, the semi-transparent film 41 is formed on the opposite side of the quantum dot layers 44R, 44G to the OLED 32, and on the opposite side of the color filters 42R, 42G to the quantum dot layers 44R, 44G.

[0075] On the other hand, on the element formation surface of the glass substrate 60, neither a color filter nor a quantum dot layer is formed so as to face the blue subpixel 21B.

[0076] A sealing film 62 that seals the color filters 42R, 42G, the quantum dot layers 44R, 44G, and the semi-transparent film 41 is formed on the entire element formation surface of the glass substrate 60 on which the color filters 42R, 42G, the quantum dot layers 44R, 44G, and the semi-transparent film 41 are formed.

[0077] Three anode electrodes 34 are formed on the sealing film 62 so as to correspond to the sub-pixels 21R, 21G, and 21B. A blue organic light-emitting layer 36 is formed on each anode electrode 34. A common cathode electrode 38 is formed on each blue organic light-emitting layer 36. In this way, in each pixel 20, an OLED 32 is formed for each of the sub-pixels 21R, 21G, and 21B, as in the first embodiment. Note that, since this embodiment is a bottom emission type, the anode electrodes 34 can be configured as transparent electrodes.

[0078] In this way, a red sub-pixel 21R is formed, which includes the blue OLED 32, the red quantum dot layer 44R, and the red color filter 42R.

[0079] Also, a green sub-pixel 21G is configured, which includes a blue OLED 32, a green quantum dot layer 44G, and a green color filter 42G.

[0080] On the other hand, on the element formation surface of the glass substrate 60, neither a color filter nor a quantum dot layer is formed so as to face the OLED 32 of the blue subpixel 21B. Therefore, the blue subpixel 21B has a blue OLED 32, but does not have a blue color filter or other color filters or a quantum dot layer. In other words, the subpixel 21B emits blue light without passing through a blue color filter or other color filters.

[0081] A sealing film 64 for sealing the OLED 32 is formed on the entire surface of the glass substrate 60 on which the cathode electrode 38 is formed.

[0082] As in the present embodiment, a pixel including three sub-pixels may be configured as a bottom emission type. In the present embodiment, the image quality can be improved in a bright environment in the same manner as in the first embodiment.

[0083] (Modification) A display device according to a modification of this embodiment will be described with reference to Fig. 10. Fig. 10 is a cross-sectional view showing a schematic configuration of a pixel of the display device according to the modification of this embodiment.

[0084] In the present embodiment, as shown in FIG. 9, the semi-transmissive film 41 is formed between the color filters 42R and 42G and the glass substrate 60, but the present invention is not limited to this.

[0085] As shown in Fig. 10, the semi-transparent film 41 may be formed between the color filter 42R and the quantum dot layer 44R, and between the color filter 42G and the quantum dot layer 44G. In the configuration shown in Fig. 10, the semi-transparent film 41 is also formed on the display surface side of the panel 2 with respect to the quantum dot layers 44R and 44G, which is the entrance side of external light with respect to the quantum dot layers 44R and 44G. Therefore, in the case shown in Fig. 10, as in the case shown in Fig. 9, the image quality can be improved in a bright environment.

[0086] [Fourth embodiment] A display device according to a fourth embodiment of the present invention will be described with reference to Fig. 11. Fig. 11 is a schematic diagram showing a schematic configuration of a pixel of the display device according to this embodiment. Note that the same components as those of the display devices according to the first to third embodiments are given the same reference numerals, and the description thereof will be omitted or simplified.

[0087] In the above first to third embodiments, the semi-transmissive film 41 is used as a light reducing film for reducing external light incident on the quantum dot layers 44R and 44G in the pixel 20, but the present invention is not limited to this. Instead of the semi-transmissive film 41, an absorbing film that absorbs light of a specific wavelength that can excite the quantum dots in the quantum dots may be used.

[0088] In this embodiment, a configuration in which an ultraviolet absorbing film is used in place of the semi-transmissive film 41 in the pixel 20 shown in FIG. 4 will be described.

[0089] 11, an ultraviolet absorbing film 71 is formed between the color filters 42R, 42G and the glass substrate 40 on the display surface side of the panel 2 with respect to the quantum dot layers 44R, 44G, instead of the semi-transparent film 41. That is, the ultraviolet absorbing film 71 is formed on the opposite side of the quantum dot layers 44R, 44G to the OLED 32, and on the opposite side of the color filters 42R, 42G to the quantum dot layers 44R, 44G. The display surface side of the panel 2 with respect to the quantum dot layers 44R, 44G is the entrance side of external light with respect to the quantum dot layers 44R, 44G.

[0090] The ultraviolet absorbing film 71 transmits visible light, while absorbing ultraviolet light that may excite the quantum dots in the quantum dot layers 44R and 44G. The ultraviolet absorbing film 71 is not particularly limited, but may be a film containing an ultraviolet absorbing material. The ultraviolet absorbing film 71 is, for example, a film containing zinc oxide, indium tin oxide (ITO), or the like as an ultraviolet absorbing material. The ultraviolet absorbing film 71 functions as a light reducing film that reduces external light incident on the quantum dot layers 44R and 44G. That is, due to the absorption of ultraviolet light by the ultraviolet absorbing film 71, it is possible to reduce the ultraviolet light in the external light incident on the quantum dot layers 44R and 44G, and to reduce the excitation of the quantum dots by ultraviolet light, thereby reducing the light emission of the quantum dot layers 44R and 44G. This makes it possible to improve image quality in a bright environment, specifically, to improve the display contrast.

[0091] In this way, according to this embodiment, it is possible to improve image quality in a bright environment.

[0092] In this embodiment, the ultraviolet absorbing film 71 that absorbs ultraviolet light is used, but the present invention is not limited thereto. In this embodiment and the fifth and sixth embodiments described later, instead of the ultraviolet absorbing film 71, a light absorbing film that absorbs light of a specific wavelength that excites the quantum dots in the quantum dot layers 44R and 44G can be widely used. For example, instead of the ultraviolet absorbing film 71, a light absorbing film that absorbs light having a wavelength equal to or less than the wavelength of blue light including ultraviolet light, specifically, light having a wavelength of, for example, 490 nm or less, can be used. Such a light absorbing film can reduce the excitation of the quantum dots and reduce the light emission of the quantum dot layers 44R and 44G. The light absorbing film can be configured to transmit at least red light and green light. In addition, the light referred to in this specification is a broad light including not only visible light but also infrared light and ultraviolet light.

[0093] (Modification) A display device according to a modification of this embodiment will be described with reference to Fig. 12. Fig. 12 is a cross-sectional view showing a schematic configuration of a pixel of the display device according to the modification of this embodiment.

[0094] In this embodiment, as shown in FIG. 11, the ultraviolet absorbing film 71 is formed between the color filters 42R and 42G and the glass substrate 40, but the present invention is not limited to this.

[0095] As shown in Fig. 12, the ultraviolet absorbing film 71 may be formed between the color filter 42R and the quantum dot layer 44R, and between the color filter 42G and the quantum dot layer 44G. In the configuration shown in Fig. 12, the ultraviolet absorbing film 71 is also formed on the display surface side of the panel 2 with respect to the quantum dot layers 44R and 44G, which is the external light intrusion side with respect to the quantum dot layers 44R and 44G. Therefore, in the case shown in Fig. 12, as in the case shown in Fig. 11, the display contrast can be improved in a bright environment.

[0096] [Fifth embodiment] A display device according to a fifth embodiment of the present invention will be described with reference to Fig. 13. Fig. 13 is a schematic diagram showing a schematic configuration of a pixel of the display device according to this embodiment. Note that the same components as those of the display devices according to the first to fourth embodiments are given the same reference numerals, and the description thereof will be omitted or simplified.

[0097] In the fourth embodiment, the case where the ultraviolet absorbing film 71 is used instead of the semi-transmissive film 41 in the configuration shown in FIG. 4 has been described, but the present invention is not limited to this.

[0098] In this embodiment, a configuration in which an ultraviolet absorbing film 71 is used instead of the semi-transmissive film 41 in the configuration shown in FIG. 7 will be described.

[0099] 13, an ultraviolet absorbing film 71 similar to that of the fourth embodiment is formed between the color filters 42R, 42G and the cover film 56 on the display surface side of the panel 2 with respect to the quantum dot layers 44R, 44G, instead of the semi-transparent film 41. That is, the ultraviolet absorbing film 71 is formed on the opposite side of the quantum dot layers 44R, 44G to the OLED 32, and on the opposite side of the color filters 42R, 42G to the quantum dot layers 44R, 44G. The display surface side of the panel 2 with respect to the quantum dot layers 44R, 44G is the entrance side of external light with respect to the quantum dot layers 44R, 44G.

[0100] As in the present embodiment, a pixel including three sub-pixels may be formed on a single glass substrate. In this embodiment, too, the image quality can be improved in a bright environment in the same manner as in the fourth embodiment.

[0101] (Modification) A display device according to a modification of this embodiment will be described with reference to Fig. 14. Fig. 14 is a cross-sectional view showing a schematic configuration of a pixel of the display device according to the modification of this embodiment.

[0102] In the present embodiment, as shown in FIG. 13, the ultraviolet absorbing film 71 is formed between the color filters 42R and 42G and the cover film 56, but the present invention is not limited to this.

[0103] As shown in Fig. 14, the ultraviolet absorbing film 71 may be formed between the color filter 42R and the quantum dot layer 44R, and between the color filter 42G and the quantum dot layer 44G. In the configuration shown in Fig. 14, the ultraviolet absorbing film 71 is also formed on the display surface side of the panel 2 with respect to the quantum dot layers 44R and 44G, which is the external light intrusion side with respect to the quantum dot layers 44R and 44G. Therefore, in the case shown in Fig. 14, as in the case shown in Fig. 13, the image quality can be improved in a bright environment.

[0104] [Sixth embodiment] A display device according to a sixth embodiment of the present invention will be described with reference to Fig. 15. Fig. 15 is a schematic diagram showing a schematic configuration of a pixel of the display device according to this embodiment. Note that components similar to those of the display devices according to the first to fifth embodiments are given the same reference numerals, and descriptions thereof will be omitted or simplified.

[0105] In the fourth embodiment, the case where the ultraviolet absorbing film 71 is used instead of the semi-transmissive film 41 in the configuration shown in FIG. 4 has been described, but the present invention is not limited to this.

[0106] In this embodiment, a configuration in which an ultraviolet absorbing film 71 is used instead of the semi-transmissive film 41 in the configuration shown in FIG. 9 will be described.

[0107] 15, an ultraviolet absorbing film 71 similar to that of the fourth embodiment is formed between the color filters 42R, 42G and the glass substrate 60 on the display surface side of the panel 2 with respect to the quantum dot layers 44R, 44G, instead of the semi-transparent film 41. That is, the ultraviolet absorbing film 71 is formed on the opposite side of the quantum dot layers 44R, 44G to the OLED 32, and on the opposite side of the color filters 42R, 42G to the quantum dot layers 44R, 44G. The display surface side of the panel 2 with respect to the quantum dot layers 44R, 44G is the entrance side of external light with respect to the quantum dot layers 44R, 44G.

[0108] As in the present embodiment, a pixel including three sub-pixels may be configured as a bottom emission type. In the present embodiment, the image quality can be improved in a bright environment in the same manner as in the fourth embodiment.

[0109] (Modification) A display device according to a modification of this embodiment will be described with reference to Fig. 16. Fig. 16 is a cross-sectional view showing a schematic configuration of a pixel of the display device according to the modification of this embodiment.

[0110] In this embodiment, as shown in FIG. 15, the ultraviolet absorbing film 71 is formed between the color filters 42R and 42G and the glass substrate 60, but the present invention is not limited to this.

[0111] As shown in Fig. 16, the ultraviolet absorbing film 71 may be formed between the color filter 42R and the quantum dot layer 44R, and between the color filter 42G and the quantum dot layer 44G. In the configuration shown in Fig. 16, the ultraviolet absorbing film 71 is also formed on the display surface side of the panel 2 with respect to the quantum dot layers 44R and 44G, which is the external light intrusion side with respect to the quantum dot layers 44R and 44G. Therefore, in the case shown in Fig. 16, as in the case shown in Fig. 15, the image quality can be improved in a bright environment.

[0112] [Modified embodiment] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0113] For example, in the above embodiment, the OLED is used as the light emitting element, but the present invention is not limited to this, and various light emitting elements can be used instead of the OLED.

[0114] In the above embodiment, the pixel 20 has three sub-pixels 21R, 21G, and 21B, but the present invention is not limited to this. The pixel 20 may have two or more sub-pixels, or may have a single sub-pixel.

[0115] In the above embodiment, the semi-transmitting film 41 or the ultraviolet absorbing film 71 is formed on the two quantum dot layers 44R and 44G, but the present invention is not limited to this. The semi-transmitting film 41 or the ultraviolet absorbing film 71 may be formed on at least one of the quantum dot layers 44R and 44G. [Explanation of symbols]

[0116] 1. Timing controller 2. Panel 3…Source drive IC 4. Gate drive IC 20…pixels 21…Subpixel 21R, 21G, 21B...Subpixels 30…Glass substrate 34...Anode electrode 36...Blue organic light-emitting layer 38…Cathode electrode 40…Glass substrate 41...Semi-permeable membrane 42R, 42G...Color filters 44R, 44G...Quantum dot layer 50…Glass substrate 60…Glass substrate 71...UV absorbing film 100... Element substrate 200...Color filter substrate D: Diode DL…Data line GL: Gate Line

Claims

1. A glass substrate; A pixel including a light emitting element formed on the glass substrate and a quantum dot layer that converts the wavelength of light emitted from the light emitting element; a first sealing film formed on the light-emitting element and sealing the light-emitting element; a light reducing film formed on the opposite side of the quantum dot layer from the light emitting element, the light reducing film reducing external light incident on the quantum dot layer; a second sealing film formed on the light reducing film and sealing the quantum dot layer and the light reducing film; a cover film formed on the second sealing film; an anti-reflection film disposed on the cover film and configured to block the emission of the external light; having the light reducing film is a semi-transmitting film that transmits a part of visible light and reflects another part of the visible light, or a light absorbing film that absorbs light having a wavelength equal to or shorter than blue light, the pixel has a first sub-pixel of a first color, a second sub-pixel of a second color, and a third sub-pixel of a third color; the light reducing film is formed on the opposite side of the color filter to the quantum dot layer; The second sealing film is in contact with the light reducing film in the first subpixel and the third subpixel, and is in contact with the first sealing film in the second subpixel. A display device comprising:

2. The light absorbing film absorbs ultraviolet light.

2. The display device according to claim 1.

3. the first subpixel has the light-emitting element that emits light of the second color, and a first quantum dot layer that converts the light of the second color into light of the first color as the quantum dot layer; the second subpixel has the light emitting element that emits light of the second color, The light reducing film is formed in the first sub-pixel.

3. The display device according to claim 1 or 2.

4. the third subpixel has the light emitting element that emits the second color light, and a second quantum dot layer that converts the second color light into the third color light as the quantum dot layer; The light reducing film is formed in the third sub-pixel.

4. The display device according to claim 3.

5. The second subpixel emits light of the second color without passing through the color filter.

5. The display device according to claim 3 or 4.

6. the first color is red or green; The second color is blue.

6. The display device according to claim 3, wherein the first and second electrodes are arranged in a first direction.

7. The semi-transparent film is a metal film.

7. The display device according to claim 1, wherein the first and second electrodes are arranged in a first direction.

8. The metal film is an aluminum film.

8. The display device according to claim 7.

9. The light absorbing film is a film containing indium tin oxide.

7. The display device according to claim 1, wherein the first and second electrodes are arranged in a first direction.

10. The light emitting element is an organic light emitting diode. The display device according to claim 1 .

11. The second subpixel does not have the quantum dot layer.

7. The display device according to claim 3, wherein the first and second electrodes are arranged in a first direction.

12. The light emitting element, the quantum dot layer, and the light reducing film are formed on one surface of the glass substrate.

12. The display device according to claim 1, wherein the first and second electrodes are arranged in a first direction.

13. The one surface side of the glass substrate is a display surface side.

13. The display device according to claim 12.

14. The anti-reflection film has a quarter wave plate on the light reducing film and a polarizing plate on the quarter wave plate.

2. The display device according to claim 1 .

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