KR102279207B1 - Display device - Google Patents

Abstract

The display device includes a light source unit, a substrate, and a color conversion layer. The light source unit provides blue light. The substrate is formed on an upper portion or a side of the light source unit and includes a plurality of pixels arranged in a matrix shape. The color conversion layer is formed under the substrate, corresponds to some or all of the pixels, and absorbs the blue light and emits the first light having a longer wavelength than the blue light; and the substrate and the light. It is formed between the conversion part, and includes a transmission reflective layer that reflects part or all of the blue light and transmits a part of the unreflected blue light and the first light.

Description

display device {DISPLAY DEVICE}

The present invention relates to a display device, and more particularly, to a photoluminescence display device.

Recently used display devices include a liquid crystal display device, an electrowetting display device, an electrophoretic display device, and the like. The display devices include light-receiving display panels and a separate backlight unit providing light to the display panels. In general, the backlight unit provides white light to the display panels, and the white light is converted into light having a specific color through a color filter provided inside the display panels and recognized by the user's eyes.

However, since the conventional display device has low light efficiency, a method for increasing the light efficiency is being sought.

SUMMARY OF THE INVENTION An object of the present invention is to provide a display device capable of increasing light efficiency.

Another object of the present invention is to provide a display device capable of increasing light efficiency and minimizing disturbance of diurnal rhythm.

The display device according to the first embodiment of the present invention includes a lower substrate including a plurality of pixel regions and a color conversion layer formed on the lower substrate. The color conversion layer corresponds to at least a portion of the pixel regions, and absorbs at least a portion of the blue light provided under the color conversion layer to emit a first light having a longer wavelength than the blue light; and a transmissive reflection layer formed on the light conversion unit and reflecting at least a portion of the unabsorbed blue light and transmitting the first light.

The light conversion unit may include a quantum dot layer. The quantum dot layer may be formed of at least one of II-VI elements, III-V elements, IV elements, and IV-VI elements.

The pixel regions include first and second pixel regions displaying different colors, the light conversion unit is formed to correspond to the first pixel region, and a red quantum dot layer absorbing the blue light to emit red light; A green quantum dot layer formed to correspond to the second pixel area and emitting green light by absorbing the blue light may be included.

In addition, the pixel regions include fourth pixel regions displaying a color different from that of the first and second pixel regions, and the light conversion unit is formed to correspond to the fourth pixel region and absorbs the blue light; A sky blue quantum dot layer emitting sky blue light having a wavelength of 444 to 484 nm may be further included.

The pixel regions may include third pixel regions displaying a color different from that of the first and second pixel regions, and may further include a transparent insulating layer formed to correspond to the third pixel regions; The transparent insulating layer may include at least one of SiO2 and SiN.

The transmissive reflection layer may include at least one of a cholesteric liquid crystal and a photonic crystal.

The color conversion layer may further include a color filter that is formed on the transmissive reflective layer, blocks the remainder of the unreflected blue light, and transmits the first light. The color filter may include a red color layer formed to correspond to the first pixel area and a green color layer formed to correspond to the second pixel area.

The display device includes a backlight unit providing the blue light to the lower substrate, the backlight unit including a light source unit emitting the blue light and a light guide plate guiding the blue light emitted from the light source unit to the color conversion layer can do. The light source unit may be a blue light emitting diode (Blue LED) emitting blue light having a wavelength of 440 to 460 nm or a deep blue LED emitting blue light having a wavelength of 430 to 450 nm.

The display device may further include a liquid crystal layer facing the lower substrate with the color conversion layer interposed therebetween, and an upper substrate formed on the liquid crystal layer. The color conversion layer may be formed between the lower substrate and the liquid crystal layer.

The display device may further include a thin film transistor layer, and the thin film transistor layer may be formed between the lower substrate and the color conversion layer or between the color conversion layer and the liquid crystal layer.

The display device may further include an organic light emitting layer emitting the blue light.

The blue light may have a wavelength of 430 to 470 nm.

The display device may further include an upper substrate on the color conversion layer. In addition, the display device may further include a thin film transistor layer, and the thin film transistor layer may be formed between the lower substrate and the organic light emitting layer.

The display device according to the first embodiment of the present invention can increase the light efficiency.

A display device according to another embodiment of the present invention may increase light efficiency and minimize disturbance of diurnal rhythm.

A display device according to another embodiment of the present invention may increase light efficiency.

1 is a schematic perspective view of a display device according to a first embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view corresponding to I-I' of FIG. 1 .
3 is a schematic cross-sectional view of a display device according to another exemplary embodiment of the present invention.
4 is a schematic cross-sectional view of a display device according to another embodiment of the present invention.

The above objects, other objects, features and advantages of the present invention will be easily understood through the following preferred embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

In order to clearly express various layers and regions in the drawings, the thicknesses are enlarged. Throughout the specification, like reference numerals are assigned to similar parts. When a part, such as a layer, film, region, plate, etc., is “on” another part, it includes not only cases where it is “on” another part, but also cases where another part is in between.

Hereinafter, a display device according to a first embodiment of the present invention will be described.

1 is a schematic perspective view of a display device according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view corresponding to I-I' of FIG. 1 .

The display device 10 according to the first exemplary embodiment includes a lower substrate 200 including a plurality of pixel areas PXL and a color conversion layer CCL.

The pixel areas PXL may include first pixel areas PXL1 , second pixel areas PXL2 , and third pixel areas PXL3 displaying different colors.

The lower substrate 200 is not particularly limited as long as it is commonly used, but may be a transparent substrate, and the transparent substrate may be a glass substrate, a quartz substrate, or a plastic substrate.

The color conversion layer CCL is formed on the lower substrate 200 , and includes a light conversion unit 300 and a transmissive reflection layer 400 formed on the light conversion unit 300 .

The light conversion unit 300 corresponds to at least a portion of the pixel areas PXL, absorbs at least a portion of the blue light L1 provided under the color conversion layer CCL, and the blue light L1 . The first lights L2 and L3 having a longer wavelength are emitted.

The light conversion unit 300 may include a quantum dot layer. Since the half-width of light emitted from the quantum dot layer is narrower than that of light through a conventional color filter or phosphor, color reproducibility is excellent.

The quantum dots forming the quantum dot layer are materials having a crystal structure of several nanometers, and are composed of hundreds to thousands of atoms. Since the quantum dots are very small in size, a quantum confinement effect appears. The quantum confinement effect refers to a phenomenon in which a band gap of an object becomes larger when an object becomes smaller than a nano size. Accordingly, when light having a wavelength higher than that of the band gap is incident on the quantum dot, the quantum dot absorbs the light and enters an excited state, and falls to a ground state while emitting light of a specific wavelength. The light of the emitted wavelength has a value corresponding to the band gap. When the size and composition of the quantum dots are adjusted, the light emission characteristics due to the quantum confinement effect can be controlled.

The composition of the quantum dot layer is not particularly limited and may include Group II-VI elements, III-V elements, IV elements, or IV-VI elements. The Group II element may be at least one selected from the group consisting of zinc cadmium and mercury. The group III element may be at least one selected from the group consisting of aluminum, gallium, and indium. The group IV element may be at least one selected from the group consisting of silicon, germanium, tin, and lead. The group V element may be at least one selected from the group consisting of nitrogen, phosphorus, and arsenic. The group VI may be any one selected from the group consisting of sulfur, selenium, and tellurium.

The light conversion unit 300 is formed to correspond to the first pixel region PXL1, and a red quantum dot layer 310 that absorbs the blue light L1 and emits the red light L2 and the second pixel region ( The green quantum dot layer 330 formed to correspond to the PXL2) and emitting the green light L3 by absorbing the blue light L1 may be included. A plurality of the red quantum dot layer 310 and the green quantum dot layer 330 may be provided in a one-to-one correspondence or a one-to-many correspondence to the first pixel regions PXL1 and the second pixel regions PXL2, respectively. .

A transparent insulating layer 600 may be formed to correspond to the third pixel areas PXL3 displaying different colors from the first pixel areas PXL1 and the second pixel areas PXL2 . The transparent insulating layer 600 transmits the blue light L1. The transparent insulating layer 600 is not particularly limited as long as it is commonly used, but may include at least one of _{SiO 2 and SiN.}

Black matrices BM1 may be provided between the quantum dot layers 310 and 330 adjacent to each other so that different first lights L2 and L3 emitted from adjacent quantum dot layers do not mix.

The color conversion layer CCL includes a transmissive reflection layer 400 formed on the light conversion unit 300 . The transmissive reflection layer 400 reflects at least a portion L4 of the unabsorbed blue light and transmits the first light L2 and L3. That is, the transmission reflective layer 400 formed on the red quantum dot layer 310 reflects (L4) at least a portion of the unabsorbed blue light, and transmits the red light (L2) converted by the red quantum dot layer 310 . . In addition, the transmissive reflection layer 400 formed on the green quantum dot layer 330 reflects (L4) at least a portion of the unabsorbed blue light and transmits the green light (L3) converted by the green quantum dot layer 330 .

The transmissive reflective layer 400 is not particularly limited as long as it is a material having a photonic band gap, but may include at least one of a cholesteric liquid crystal and a photonic crystal. Materials having a band gap are materials having a crystal structure, and periodic potentials are generated due to the regular arrangement of atoms or molecules constituting the material, thereby affecting the movement of electrons. Due to this, a band gap is formed, and this band gap prevents the propagation of electrons having a specific energy.

The cholesteric liquid crystal, the photonic crystal, etc. are materials having an optical band gap and block the progress of electrons corresponding to the blue light region. Accordingly, the transmissive reflection layer 400 includes the cholesteric liquid crystal and the photonic crystal, and thus can maximize the reflection (L4) efficiency of the unabsorbed blue light.

The color conversion layer CCL may further include a color filter 500 formed on the transmissive reflection layer 400 . The color filter 500 blocks the remainder L5 of the blue light not reflected by the transmission/reflection layer 400 and transmits the first light L2 and L3. The first light L2 and L3 may be a red light L2, a green light L3, or the like.

The color filter 500 may include a red color layer 510 and a green color layer 530 . The red color layer 510 may be formed to correspond to the first pixel region PXL1 in which the red quantum dot layer 310 is formed, and the green color layer 530 may include the green quantum dot layer 330 . It may be formed to correspond to the second pixel area PXL2 . The red color layer 510 transmits the red light L2 that has passed through the transmission/reflection layer 400 and blocks the blue light L5 that is not reflected by the transmission/reflection layer. The green color layer 530 transmits the green light L3 that has passed through the transmissive reflective layer 400 and blocks the blue light L5 that is not reflected by the transmissive reflective layer. The color filter may be formed by patterning using photolithography, or may be formed by an inkjet method or the like. Also, although not shown, a color layer representing blue and other colors may be further included.

Also, a black matrix BM2 may be formed between the color layers 510 and 530 so that the transmitted first lights L2 and L3 are not mixed. The black matrix BM2 may be formed before, after, or simultaneously with the step of forming the color filter 500 . The black matrix BM2 may be formed by forming a light blocking layer that absorbs light and patterning the light blocking layer using photolithography, and may optionally be formed by another method, for example, an inkjet method.

The display device 10 may include a backlight unit 100 including a light source unit 110 and a light guide plate 130 . The light source unit 110 emits the blue light L1 , and the light guide plate 130 guides the blue light L1 emitted from the light source unit 110 to the color conversion layer CCL. The light source unit 110 is not particularly limited as long as it is a unit 30 emitting blue light L1, but a blue light emitting diode (Blue LED) emitting blue light L1 having a wavelength of 440 to 460 nm or 430 to 450 nm. It may be a deep blue LED emitting blue light L1 having a wavelength.

The display device 10 further includes a liquid crystal layer LC facing the lower substrate 200 with the color conversion layer CCL interposed therebetween and an upper substrate 700 formed on the liquid crystal layer LC. can do.

The liquid crystal layer LC is not particularly limited as long as it is commonly used, but may include a plurality of liquid crystal molecules having dielectric anisotropy. The liquid crystal layer LC is formed by being inserted between the lower substrate 200 and the upper substrate 700 . The display device 10 may adjust the amount of transmitted light by applying an electric field to the liquid crystal layer LC to rearrange the liquid crystal molecules of the liquid crystal layer LC.

The upper substrate 700 is not particularly limited as long as it is commonly used, but may be a transparent substrate, and the transparent substrate may be a glass substrate, a quartz substrate, or a plastic substrate. Also, the upper substrate 700 may include a common electrode for driving the liquid crystal molecules.

The display device 10 may further include a thin film transistor layer 800 , and the thin film transistor layer 800 may be formed between the lower substrate 200 and the color conversion layer CCL. In addition, the thin film transistor layer 800 may be formed between the color conversion layer CCL and the liquid crystal layer LC. The thin film transistor layer 800 may include at least one thin film transistor (not shown) and a pixel electrode (not shown) for driving the liquid crystal molecules.

The display device 10 according to the first embodiment of the present invention includes the light conversion unit 300 and the transmission/reflection layer 400 to maximize light efficiency.

Hereinafter, a display device according to another embodiment of the present invention will be described. Hereinafter, differences from the above-described display device according to the first embodiment of the present invention will be described in detail, and parts not described above are based on the display device according to the first embodiment of the present invention.

3 is a schematic cross-sectional view of a display device according to another exemplary embodiment of the present invention.

Referring to FIG. 3 , a display device 20 according to another embodiment of the present invention includes a lower substrate 200 including a plurality of pixel regions PXL and a color conversion layer formed on the lower substrate 200 ( CCL). The color conversion layer CCL is formed on the lower substrate 200 , and includes a light conversion unit 300 and a transmissive reflection layer 400 formed on the light conversion unit 300 .

The pixel areas PXL include fourth pixel areas PXL4 different from the first to third pixel areas PXL1 , PXL2 , and PXL3 .

The light conversion unit 300 may further include a sky blue quantum dot layer 350 . The sky blue quantum dot layer 350 is formed to correspond to the fourth pixel region PXL4, absorbs the blue light L1, and emits the sky blue light L6 having a wavelength of 444 to 484 nm. A plurality of the sky blue quantum dot layers 350 may also be provided in a one-to-one correspondence or a one-to-many correspondence to the fourth pixel regions PXL4 .

The color filter 500 corresponding to the fourth pixel area PXL4 may include a color layer (not shown) corresponding to sky blue, or may be replaced with a transparent insulating layer 600 as shown in FIG. 2 . have. Since the sky blue light L6 corresponds to the blue light region, a separate color filter is not necessarily required.

The display device 20 may include the fourth pixel area PXL4 to implement a display device having a pixel structure of four colors.

When blue light with a wavelength of 464 nm reaches the retina during the day, seronin, which has an arousal effect, is produced. The seronin is converted into melatonin at night, and the melatonin can effectively treat depression, insomnia, and sleep disorders. However, when blue light with a wavelength of 464 nm reaches the retina at night, melatonin secretion is suppressed due to the arousal effect, thereby disturbing insomnia and circadian rhythm.

Therefore, when the display device 20 is used during the daytime, the sky blue light does not participate in melatonin suppression, so it can be used as a four-color pixel structure, and when used at night, it emits sky blue light capable of suppressing melatonin. By turning off the fourth pixel areas PXL4 to use the three-color pixel structure, it is possible to minimize disturbance in one cycle.

That is, the display device 20 according to another embodiment of the present invention includes the light conversion unit 300 and the transmission/reflection layer 400 to maximize light efficiency, and when the display device 20 is used at night, , by minimizing the emission of blue light having a wavelength of 464 nm, it is possible to minimize insomnia and circadian disturbance caused by suppressed melatonin secretion.

Next, a display device according to another exemplary embodiment of the present invention will be described. Hereinafter, differences from the display device according to the first embodiment of the present invention described above will be described in detail, and parts that are not described are based on the display device according to the first embodiment of the present invention described above.

4 is a schematic cross-sectional view of a display device according to another embodiment of the present invention.

Referring to FIG. 4 , the display device 30 includes a lower substrate 200 including a plurality of pixel regions PXL, an organic emission layer EM and a color conversion layer CCL formed on the lower substrate 200 . ) is included. The color conversion layer CCL is formed on the organic light emitting layer EM, and includes a light conversion unit 300 and a transmissive reflection layer 400 formed on the light conversion unit 300 .

The organic light emitting layer EM is formed on the lower substrate 200 and provides blue light L1 . Although not limited thereto, the blue light L1 may have a wavelength of 430 to 470 nm.

Anodes 910 may be formed on the lower substrate 200 , and the organic emission layer EM is formed on the anodes 910 . A cathode 930 is formed on the organic emission layer EM. The organic light emitting layer (EM) is

The display device 30 may further include a thin film transistor layer 800 . The thin film transistor layer 800 may be formed between the lower substrate 200 and the organic emission layer EM. The display device 30 may emit blue light L1 by applying an electric field to the organic emission layer EM.

The display device 30 according to another embodiment of the present invention includes the light conversion unit 300 and the transmission/reflection layer 400 to maximize light efficiency.

As mentioned above, although embodiments of the present invention have been described with reference to the accompanying drawings, those of ordinary skill in the art to which the present invention pertains can practice the present invention in other specific forms without changing its technical spirit or essential features. You will understand that there is Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

10, 20, 30: display device 100: backlight unit
110: light source unit 130: light guide plate
200: lower substrate 300: light conversion unit
310: red quantum dot layer 330: green quantum dot layer
350: sky blue quantum dot layer 400: transmission reflective layer
500: color filter 510: red color layer
530: green color layer 550: sky blue color layer
600: transparent insulating layer 700: upper substrate
800: thin film transistor layer 910: anode
930: cathode

Claims (19)

a lower substrate including a plurality of pixel regions; and
a color conversion layer formed on the lower substrate;
The color conversion layer is
a first conversion unit corresponding to a first pixel area of the pixel areas and absorbing a first light of a first color to emit a second light of a second color different from the first color; and a second of the pixel areas. a light conversion unit corresponding to the pixel area and including a second conversion unit which absorbs the first light and emits a third light of the first color and a third color different from the second color;
a transmissive reflection layer disposed on the first converting unit and the second converting unit, reflecting the first light and transmitting the second light and the third light; and
a color filter disposed on the transmission/reflection layer, the color filter including a first color layer corresponding to the first conversion unit and having the second color and a second color layer corresponding to the second conversion unit and having the third color A display device comprising a. The display device of claim 1 , wherein the light conversion unit includes a quantum dot layer. The display device of claim 2 , wherein the quantum dot layer is made of at least one of Group II-VI elements, III-V elements, IV elements, and IV-VI elements. According to claim 1, wherein the first conversion unit comprises a red quantum dot layer for emitting the second light by absorbing the first light,
and the second conversion unit includes a green quantum dot layer absorbing the first light and emitting the third light. The display device of claim 4 , wherein the light conversion unit further comprises a transparent insulating layer corresponding to a third pixel area among the pixel areas. The method according to claim 5, wherein the light conversion unit further comprises a sky blue quantum dot layer corresponding to a fourth pixel area among the pixel areas, absorbing the first light, and emitting sky blue light having a wavelength of 444 to 484 nm. display device included. The display device of claim 5 , wherein the transparent insulating layer includes at least one _{of SiO 2 and SiN.} The display device of claim 1 , wherein the transmission and reflection layer includes at least one of a cholesteric liquid crystal and a photonic crystal. delete delete The method of claim 1 , wherein the display device comprises a backlight unit providing the first light to the lower substrate;
The backlight unit includes a light source unit emitting the first light and a light guide plate guiding the first light emitted from the light source unit to the color conversion layer. According to claim 11, wherein the light source unit is a blue light emitting diode (Blue LED) for emitting the first light having a wavelength of 440 to 460 nm or a deep blue light emitting diode for emitting the first light having a wavelength of 430 to 450 nm (Deep blue LED) is a display device. The display device of claim 1 , further comprising a liquid crystal layer facing the lower substrate with the color conversion layer interposed therebetween, and an upper substrate formed on the liquid crystal layer. 14. The method of claim 13, wherein the display device further comprises a thin film transistor layer,
The thin film transistor layer is formed between the lower substrate and the color conversion layer or between the color conversion layer and the liquid crystal layer. The display device of claim 1 , further comprising an organic light emitting layer disposed between the color conversion layer and the lower substrate and emitting the first light. delete delete delete a substrate including a plurality of pixel regions; and
a color conversion layer formed on the substrate;
The color conversion layer is
a first conversion unit corresponding to a first pixel area of the pixel areas and absorbing a first light of a first color to emit a second light of a second color different from the first color; and a second of the pixel areas. a light conversion unit corresponding to the pixel area and including a second conversion unit which absorbs the first light and emits a third light of the first color and a third color different from the second color; and
and a transmissive reflection layer overlapping the first conversion unit and the second conversion unit, reflecting the first light and transmitting each of the second light and the third light.

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