Circularly polarized light emitting display device

Abstract

The present invention relates to a circularly polarized light emitting display device comprising a reflective electrode, a light emitting diode layer, a circular polarization layer, and a selective reflection layer which is provided between the light emitting diode layer and the circular polarization layer, and at least a portion of which is configured in a direction identical or opposite to the light transmission rotation direction of the circular polarization layer. The circularly polarized light emitting display device according to the present invention can perfectly prevent reflected light caused by reflection of external incident light, without causing a decrease in efficiency of OLED light emission.

Description

Circularly polarized light-emitting display device

[0001] The present invention relates to a circularly polarized light emitting display device capable of minimizing light loss.

[0002] Emissive display technologies such as OLED use circular polarizers to control the degradation of ambient contrast caused by surface reflection of ambient light incident from the display. These circular polarizers are commonly referred to in the display industry as "OLED polarizers."

[0003] An OLED circular polarizer converts linearly polarized light into right-handed circularly polarized light (RCP) or left-handed circularly polarized light (LCP) by stacking a linear polarizer and a quarter-wave plate (QWP) that is one-quarter the wavelength (λ) of light. The QWP is positioned at an angle of +45 degrees or -45 degrees with respect to the linear polarizer. Alternatively, a broadband circular polarizer (QWP) that operates over a wider wavelength range can be constructed by combining a linear polarizer, a QWP, and a half-wave plate (HWP), in which case the QWP and HWP are positioned at an angle of 75 degrees and 15 degrees, respectively.

[0004] Figure 1 illustrates the concept of an OLED with a conventional vertical polarizer applied. Referring to Figure 1, a circularly polarized polarizer converts externally incident unpolarized light into RCP or LCP conditions and introduces it into the OLED display. This light is reflected after passing through the reflective electrodes (anode, cathode, etc.) inside the OLED. The reflected light passes through the QWP again and incurs an additional 1 / 4 λ phase retardation. Consequently, the phase retardation (1 / 4 λ) generated upon initial incidence and the additional phase retardation (1 / 4 λ) upon reflection combine to form a 1 / 2 λ phase retardation, which is converted to a linearly polarized state. This forms a linearly polarized condition rotated 90 degrees with respect to the optical axis of the polarizer, and the reflection of external light is completely blocked due to the crossed polarizer effect. Through this, the OLED completely blocks external light, providing a perfect black condition and maximizing display contrast and quality.

[0005] Figure 2 illustrates another conventional OLED structure. Referring to Figure 2, the conventional technology suffers from a problem in that the light efficiency decreases below 50% when passing through a circular polarizer. This is because light loss is inevitable in the linear polarizer positioned above the QWP. Consequently, while external light reflection can be reduced, the light emitted from the OLED is lost after passing through the color filter, reducing the light emission efficiency to below 50%.

[0006] In summary, while OLED circular polarizers offer the advantage of completely blocking external light reflection, they also suffer from the fatal drawback of reduced OLED luminous efficiency. This loss of luminance shortens the overall lifespan of OLED displays and makes it difficult to overcome the dark screen problem.

[0007] The purpose of the present invention is to provide a circular polarization light-emitting display device that can secure circular polarization by matching conventional OLED light emission to an OLED polarizer and improve light-emitting efficiency by matching with OLED Pol.

[0008] As a means of solving the problem, according to the present disclosure, a circular polarization light-emitting display device can be provided, which includes a reflective electrode, a light-emitting element layer, a circular polarization layer, and a selective reflection layer provided between the light-emitting element layer and the circular polarization layer, at least a portion of which is configured in the same or opposite direction to the light transmission rotation direction of the circular polarization layer.

[0009] Meanwhile, the selective reflection layer can be configured to have different transmittance depending on the direction of rotation of the light.

[0010] Meanwhile, the selective reflection layer may have a twisted structure and include a chiral optical structure having a pitch of tens to hundreds of nm in length.

[0011] Meanwhile, a chiral optical structure can have an optical effect of rotating incident light to the left or right.

[0012] Meanwhile, the chiral optical structure may include an optical helical structure.

[0013] Additionally, the chiral optical structure may be a chiral molecule, a liquid crystal having refractive index anisotropy (Δn), or a mesognic molecule.

[0014] Meanwhile, the selective reflection layer can be configured so that the reflection wavelength (Δλ-chiral) of the chiral optical structure is greater than or equal to the emission wavelength (Δλ-Emission) of the light-emitting element layer.

[0015] Additionally, the center wavelength of the reflection wavelength bandwidth of the chiral optical structure may include a wavelength position within 200 nm to 2000 nm.

[0016] Meanwhile, the chiral optical structure can be configured to reflect light corresponding to the chiral photonic band gap reflection wavelength.

[0017] Meanwhile, the chiral optical structure may have a first-direction rotation structure so that among unpolarized incident light generated from the light-emitting element layer, light in a first-direction circularly polarized state, which is the same as the rotation direction of the chiral optical structure, is reflected to the light-emitting element layer, and light in a second-direction circularly polarized state, which is opposite to the first direction, is transmitted.

[0018] Furthermore, the circular polarization layer may have left circular polarization or right circular polarization characteristics to suppress reflection of external light, and may be configured to have a linear polarizer and one or two optical retardations.

[0019] Additionally, the circularly polarizing layer may have a second directional polarization characteristic so that second directional polarized light that matches the circular polarization rotation of the circularly polarizing layer can pass through it.

[0020] Meanwhile, light in a first directional polarization state, which is a circular polarization component that is the same as the rotational direction of the chiral optical structure in the selective reflection layer, can be reflected in a second directional polarization state, which is a circular polarization state in the opposite direction of the rotation of the chiral optical structure, in the reflective electrode.

[0021] Meanwhile, the light whose circular polarization direction is converted and reflected into a second directional polarization state, which is a circular polarization rotation state that is the same as the rotation direction of the anti-reflection circular polarization light in which the linear polarizer and the phase retardation layer are laminated, can pass through the light-emitting element layer, the selective reflection layer, and the circular polarization layer and be emitted.

[0022] In addition, the timing of the first light generated from the light-emitting element layer and the timing of the second light reflected from the selective reflection layer and the reflective electrode are combined with different timings of circular polarization to match the polarization rotation direction of the anti-reflection layer of the circular polarizer including the final linear polarizer and the phase delay layer, so that the light-emitting efficiency of the light-emitting display can be improved without optical loss due to the polarizer.

[0023] Additionally, the selective reflection layer may be configured to include a chiral liquid crystal layer so that the refractive indices of n1 and n2 can appear in rotational repetition.

[0024] Meanwhile, the chiral layer can be manufactured through a process that makes the chiral structure have left-handed chirality and / or right-handed chirality.

[0025] Meanwhile, the chiral layer is configured so that the rotational force per unit length changes according to the temperature change of the chiral structure, and can be configured so that the wavelength of the reflected light becomes shorter or, conversely, longer as the temperature of the chiral structure increases.

[0026] Meanwhile, it is composed of organic, inorganic, organic-inorganic hybrid, quantum dot, perovskite, quantum nanowire, organic light-emitting semiconductor, and can have at least one polarizer.

[0027] In addition, the circular polarizer is configured to have a linear polarizer and a quarter wave retardation, so that the final incident linear polarized light is reflected from the light-emitting display and the final incident linear polarized light is rotated by 90 degrees due to the phase retardation (1 / 4) and the reflection phase retardation (1 / 4) that returns when reflected from the light-emitting element, thereby blocking the reflection of light incident on the light-emitting display through orthogonal polarization (Crossed Polarization), and the light-emitting display can emit light in a circularly polarized state.

[0028] Meanwhile, it is combined with a circular polarizer and may further include a linear polarizer.

[0029] Furthermore, the circular polarizer can be configured to include a linear polarizer and a half wave plate to enable a wide wavelength circular polarization function.

[0030] Meanwhile, the chiral layer can be formed integrally with the light-emitting element layer.

[0031] Additionally, the chiral layer can be formed integrally with the circular polarization layer.

[0032] Meanwhile, the chiral layer may be composed of a material having photocurable properties by ultraviolet rays.

[0033] Additionally, the chiral layer can be patterned and manufactured using a photolithography process using a photo mask.

[0034] Meanwhile, the chiral layer may be composed of a mono or diacrylate molecular structure, or may include an epoxy, epoxy acrylate, or thiol, which may induce a polymer curing reaction with visible light or ultraviolet light, or may include a component that may be decomposed.

[0035] Meanwhile, the chiral layer can be configured so that the pitch of the chiral structure is different for each pixel.

[0036] Meanwhile, the pitch of the chiral structure is composed of at least two, and can be fixed by curing at different temperatures.

[0037] Furthermore, the chiral layer can be composed of 100 nm to 10 mm.

[0038] Meanwhile, chiral layers can be composed of multiple layers.

[0039] Additionally, each chiral layer can be configured to have a different reflection wavelength.

[0040] Meanwhile, each chiral layer can be configured with the same or opposite rotational properties of the chiral structure.

[0041] Meanwhile, the polarization direction of the circular polarization layer can be configured to be the same as at least one of the plurality of chiral layers.

[0042] Additionally, the chiral layer is provided for each pixel of the light-emitting element, and may be provided in a different size in at least one pixel.

[0043] In addition, the chiral layer can be configured to enable the configuration of a photo pattern by light through the above process, and can be configured as a layer that controls the circular polarization characteristics of the same or different colors.

[0044] The circularly polarized light emitting display device according to the present invention has the effect of completely preventing reflection of reflected light from external incident light and preventing a decrease in the efficiency of OLED light emission.

[0045] Figure 1 shows the concept of an OLED to which a conventional vertical polarizer is applied.

[0046] Figure 2 is a drawing showing another example of a conventional OLED structure.

[0047] FIG. 3A is a cross-sectional view of a pixel in a circularly polarized light emitting display device according to the first embodiment of the present disclosure.

[0048] FIG. 3b is a cross-sectional view of a pixel in a modified example of a circularly polarized light emitting display device according to the first embodiment of the present disclosure.

[0049] FIG. 3c is a cross-sectional view of a pixel in another modified example of a circularly polarized light emitting display device according to the first embodiment of the present disclosure.

[0050] FIG. 4a and FIG. 4b are conceptual diagrams illustrating optical rotation in the first embodiment of the present disclosure.

[0051] Figure 5 is a conceptual diagram illustrating the rotation concept of a chiral structure in the present disclosure.

[0052] FIG. 6a is a conceptual diagram illustrating a primary light path by a chiral layer in the second embodiment of the present disclosure.

[0053] FIG. 6b is a conceptual diagram illustrating a secondary light path by a chiral layer in the second embodiment of the present disclosure.

[0054] FIG. 6c is a conceptual diagram illustrating the final path of secondary light by a chiral layer in the second embodiment of the present disclosure.

[0055] FIG. 7 is a conceptual diagram illustrating a chiral structure in one embodiment of the present disclosure.

[0056] FIGS. 8a, 8b, 8c and 8d are conceptual diagrams illustrating a process for generating a chiral layer in a circularly polarized light emitting display device according to another embodiment of the present disclosure.

[0057] Figure 9 is a drawing illustrating the concept of forming a chiral layer using a photolithography process.

[0058] FIG. 10 is a drawing showing an example of the molecular structure of a chiral structure in another embodiment of the present disclosure.

[0059] FIG. 11 is a diagram illustrating the pitch of liquid crystal molecules in a chiral layer in one embodiment of the present disclosure.

[0060] Figure 12 is a graph showing the wavelength of light selectively reflected from a chiral liquid crystal depending on temperature.

[0061] Figure 13 is a graph showing the change in pitch of a chiral structure according to temperature.

[0062] Figure 14 is a conceptual diagram showing the optical path of a circularly polarized light emitting display device in one embodiment of the present disclosure.

[0063] FIG. 15 is a conceptual diagram illustrating a variation of a pattern of a chiral layer in another embodiment of the present disclosure.

[0064] FIG. 16 is a conceptual diagram illustrating another variation of the pattern of a chiral layer in another embodiment of the present disclosure.

[0065] Figure 17 is a conceptual diagram showing the structure of a vertically stacked OLED (Tandem OLED).

[0066] FIG. 18 is a graph illustrating a multilayer chiral layer and a half-wavelength in one embodiment of the present disclosure.

[0067] FIG. 19 is a graph illustrating a multilayer chiral layer and a half-wavelength in another embodiment of the present disclosure.

[0068] FIG. 20 is a conceptual diagram illustrating a molecular structure included in a chiral layer in another embodiment of the present disclosure.

[0069] Hereinafter, a circularly polarized light emitting display device according to an embodiment of the present invention will be described in detail with reference to the attached drawings. In the following description of the embodiments, the names of each component may be referred to by different names in the art. However, if there is functional similarity and identity between them, even if a modified embodiment is adopted, it can be viewed as an equivalent configuration. In addition, the symbols added to each component are described for the convenience of explanation. However, the content depicted in the drawings in which these symbols are described does not limit each component to the scope within the drawings. Similarly, even if an embodiment with some modifications to the configuration in the drawings is adopted, it can be viewed as an equivalent configuration if there is functional similarity and identity. In addition, if it is recognized as a component that should be included naturally in light of the general level of a technician in the relevant technical field, a description thereof will be omitted.

[0070] FIG. 3A is a cross-sectional view of a pixel in a circularly polarized light emitting display device according to the first embodiment of the present disclosure.

[0071] Referring to FIG. 3a, a circularly polarized light-emitting display device according to the first embodiment of the present disclosure may be configured to include a light-emitting unit (100), a chiral layer (200), and a circularly polarizing layer.

[0072] In the present disclosure, the light-emitting unit (100) may refer to an OLED or other light-emitting display. The light-emitting unit (100) may be configured to include one or more reflective electrodes (110) to efficiently emit light.

[0073] The reflective electrode (110) can contribute to optimizing display performance by reflecting the emitted light in a specific direction. At this time, the circular polarization of the reflected light can be reversed.

[0074] The chiral layer (200) may include a rotationally symmetric structure (chiral structure) of nanometer size corresponding to the wavelength of light. In the present disclosure, the chiral structure may form a rotational structure by twisting to the left or right. The chiral structure plays a role in manipulating the circular polarization component of light and may exhibit optical activity related to the rotational nature of light. The chiral layer (200) is a selective reflection layer and is configured to reflect light of a selective wavelength. The twisted structure of the chiral layer (200) may have a pitch of tens to hundreds of nm.

[0075] The circular polarizing layer is configured to selectively transmit polarized light in one direction and block the rest. In the present embodiment, the circular polarizing layer may include a circular polarizer. The circular polarizer is configured to control the reflection of OLED emitted light and external light, thereby improving the contrast and efficiency of the display.

[0076] In the present disclosure, a chiral layer (200) is provided between a circular polarizer and a light-emitting portion (100) to enhance contrast and improve luminous efficiency. In addition, light incident from the outside can be completely blocked. In addition, the chiral layer (200) in the present disclosure can be configured to have a thickness of 100 nm to 10 mm.

[0077] FIG. 3b is a cross-sectional view of a pixel in a modified example of a circularly polarized light-emitting display device according to the first embodiment of the present disclosure, and FIG. 3c is a cross-sectional view of a pixel in another modified example of a circularly polarized light-emitting display device according to the first embodiment of the present disclosure.

[0078] Referring to FIG. 3b, in a modified example of the circularly polarized light-emitting display device (2) according to the first embodiment of the present disclosure, the circularly polarized layer may be configured to include a linear polarizer (320) and a phase retardation plate (310), and may be configured to block light in a specific direction. Specifically, the circularly polarized layer may be configured to have a 1 / 4 phase or retardation (quarter wave retardation) with the linear polarizer (320). When external light is reflected from the reflective electrode (110) of the light-emitting display, a phase retardation (1 / 4) and a reflection phase retardation (1 / 4) that returns when reflected from the light-emitting element (120) may appear. Therefore, it can function to block the reflection of light incident on the light-emitting display through orthogonal polarization (Crossed Polarization) in the form of 90 degrees rotation of linear polarization.

[0079] Referring to FIG. 3c, in another modified example of the circularly polarized light-emitting display device (3) according to the first embodiment of the present disclosure, the circularly polarized layer may include a linear polarizer (320), a QWP (312), and an HWP (311). Accordingly, incident external light may be blocked by the circularly polarized layer according to the reflection phase delay within the light-emitting layer.

[0080] FIG. 4a and FIG. 4b are conceptual diagrams illustrating optical rotation in the first embodiment of the present disclosure.

[0081] Referring to Fig. 4a, a chiral photonic structure (CPS, 200) is composed of a helical dielectric structure with a period of several hundred nanometers corresponding to the wavelength of light, and has the characteristic of selectively controlling the rotational component of light. For example, if a chiral optical structure has a right-handed chiral component, unpolarized light is split into two components when it encounters this structure.

[0082] Right circular polarization (RCP), which accounts for about 50% of unpolarized light, is reflected by the chiral structure and returns to its original direction, while left circular polarization (LCP), which accounts for the remaining 50%, passes through the chiral structure and continues to propagate. In this process, the chiral structure acts as a selective filter that reflects the component (RCP) in the same direction as its own rotation and transmits the component (LCP) in the opposite direction without restriction. The reflected light component becomes right-handed circularly polarized light (CPL). Conversely, the transmitted light becomes left-handed CPL.

[0083] Referring to Fig. 4b, a wavelength range for selectively controlling rotational components can be determined depending on the pitch of the chiral structure. Depending on the pitch of the chiral structure, a portion of the light is reflected within a certain region (Δλ), while the remainder is transmitted. In this case, the rotational properties of the transmitted and reflected light may be opposite to each other.

[0084] Furthermore, since this structure does not include color filters or absorbent dyes, light energy is not absorbed or lost. Consequently, light energy can be maximized during reflection and transmission without loss of efficiency due to absorption.

[0085] Figure 5 is a conceptual diagram illustrating the rotation concept of a chiral structure in the present disclosure.

[0086] Referring to FIG. 5, the chiral structure can be formed as a left-handed structure or a right-handed structure.

[0087] FIG. 6a is a conceptual diagram illustrating the path of primary light by a chiral layer (200) in the second embodiment of the present disclosure.

[0088] Referring to FIG. 6a, in the second embodiment of the present disclosure, the circular polarizer is configured to enable left-hand circular polarization, and the chiral layer (200) may include a right-hand rotation chiral resonator.

[0089] The light-emitting portion (100) may include one or more light-emitting elements (110) and reflective electrodes (120). A chiral layer (200) may be provided on the upper side of the light-emitting portion (100). Since the chiral layer (200) includes a right-handed chiral structure, unpolarized light emitted from the OLED (Unpolarized OLED Emission) interacts with the chiral structure and is split into two.

[0090] First, when unpolarized OLED light passes through a right-handed rotational chiral structure (R-Chiral), the right-handed circular polarization (RCP) component, which is oriented in the same direction as the chiral structure, is reflected by the chiral structure. The reflected RCP component does not pass through the chiral structure again and is recycled back into the OLED.

[0091] On the other hand, the left circular polarization (LCP) component, which is opposite to the rotational direction of the chiral structure, passes through the chiral structure and propagates toward the polarizer (300). The RCP component of the emitted light is reflected and reused, and only the LCP component is transmitted and ultimately transmitted to the outside of the display.

[0092] At this time, 50% of the left-hand circular polarization (LCP) that has passed through the right-hand rotation chiral structure matches the left-hand circular polarizer (LCP) placed in the polarizer (300), and ultimately passes through the polarizer (300) without loss while maintaining 50% of the luminous efficiency.

[0093] At this time, if the light that primarily passes through the left-hand circular polarizer is called the first left-hand luminescence component (Left CPL), the first left-hand luminescence component is transmitted without loss in the circular polarizer (310) with the same rotation, and the light with the opposite rotation to the first left-hand luminescence component is blocked from being transmitted.

[0094] FIG. 6b is a conceptual diagram illustrating a secondary light path by a chiral layer (200) in the second embodiment of the present disclosure.

[0095] Referring to Fig. 6b, first, 50% of the right-handed circularly polarized light (RCP) that is reflected from the right-handed rotation chiral structure (R-Chiral) and returns inside the OLED is 100% reflected by the reflective electrode (110) inside the OLED and re-emitted. At this time, during the reflection process, all RCP light is converted into left-handed circularly polarized light (LCP).

[0096] The LCP light thus converted is then incident on a right-handed circularly polarized structure (R-Chiral), which reflects right-handed circularly polarized light (RCP) that matches its own rotational direction, while transmitting left-handed circularly polarized light (LCP) that has the opposite rotational direction without absorption. As a result, the light converted to LCP passes through R-Chiral without loss, and the light converted to a circularly polarized state is efficiently recycled.

[0097] FIG. 6c is a conceptual diagram illustrating the final path of secondary light by the chiral layer (200) in the second embodiment of the present disclosure.

[0098] Referring to Fig. 6c, the reflected and returned left-hand circular polarization (LCP) light that has passed through the R-Chiral finally passes through the left-hand circular polarization OLED polarizer. At this time, the secondary LCP light is ultimately obtained as is without any light loss through the circular polarization matching of the LCP circular polarizer.

[0099] Therefore, the overall OLED luminance is increased by the efficiency of the secondary LCP emission added to the primary LCP emission, and the overall OLED luminance utilizes all the light generated by the primary OLED. Theoretically, considering the losses incurred in the circular polarizer of conventional OLEDs, the luminance efficiency can be increased by up to twice that of conventional OLEDs.

[0100] FIG. 7 is a conceptual diagram illustrating a chiral structure in one embodiment of the present disclosure.

[0101] Referring to Figure 7, the chiral photonic structure is tuned to the emission wavelength of a specific OLED or light-emitting device by controlling the rotational length (pitch, p) of the chiral helix, or through the refractive index and anisotropy (Δn) of the liquid crystal material and other mesogenic materials made of birefringent materials. This tuning can correspond to various emission wavelengths such as red, green, blue, yellow / green, and orange.

[0102] The wavelength of the color that filters the formed reflection return and circular polarization is adjusted by adjusting the center wavelength (λc) and wavelength width (Δλ) to match the emission wavelength of the luminescent light. The relationship is as follows:

[0103] Center wavelength position: λc = navg · p (Equation 1)

[0104] Photonic band gap (wavelength): Δλ = Δn · p (Equation 2)

[0105] navg is the average value of the refractive indices n1 and n2: navg = (n1 + n2) / 2 (Equation 3)

[0106] Δn is the difference between n1 and n2: Δn = n1 - n2 (Equation 4)

[0107] Through these relationships, the properties of chiral photonic structures can be adjusted to optimize the color and efficiency of light-emitting devices.

[0108] FIGS. 8a, 8b, 8c and 8d are conceptual diagrams illustrating a process for generating a chiral layer (210, 220, 230) in a circularly polarized light emitting display device according to another embodiment of the present disclosure.

[0109] In the present disclosure, the display can generate subpixels, generate an encapsulation layer (130), and then form a chiral layer. The chiral layer can be generated by forming a black bank (140) in an R / G / B subpixel, and then curing a chiral liquid crystal layer with controlled pitch and rotation in each subpixel.

[0110] Referring to Fig. 8a, the first chiral layer (210) can be cured in a state adjusted to have the longest pitch in order to amplify blue light. At this time, the material (1000) can be applied at a position corresponding to the blue light-emitting element (111) while being adjusted to the first temperature (T1).

[0111] Referring to FIG. 8b, the second chiral layer (220) may be formed at a position corresponding to the green light-emitting element (112) to amplify green light. At this time, the material (1000) may be applied and cured while the temperature is adjusted to the second temperature (T2) to have an intermediate pitch.

[0112] Referring to Fig. 8c, the third chiral layer (230) may be formed at a position corresponding to the red light-emitting element (113) to amplify red light. At this time, the material (1000) may be applied and cured while the temperature is adjusted to the third temperature (T3) to have an intermediate pitch.

[0113] Referring to Fig. 8d, the rotational twist pitch of the chiral liquid crystals within each chiral layer (210, 220, 230) can be maintained in a fixed state. Of course, the change in pitch according to temperature can be considered when adjusted to room temperature or operating temperature, and the chiral liquid crystal pitch can be determined by compensating in advance. Thereafter, a circular polarizer (300) can be provided on the outside of the chiral layer (210, 220, 230). At this time, the rotational property of the circular polarizer can be opposite to that of the chiral structure.

[0114] Meanwhile, the ink for forming the first chiral layer (210), the second chiral layer (220), and the third chiral layer (230) may be of the same material. However, each chiral layer (210, 220, 230) may be cured by UV after being adjusted to a predetermined temperature so as to control the pitch of the chiral liquid crystal. At this time, the first chiral layer (210) that amplifies blue light may be cured after being adjusted to the highest temperature. Next, the second chiral layer (220) that amplifies green light may be cured after being adjusted to a lower temperature than the first chiral layer (210). Finally, the third chiral layer (230) that amplifies red light may be cured after being adjusted to the lowest temperature.

[0115] Figure 9 is a drawing illustrating the concept of forming a chiral layer (200) using a photolithography process.

[0116] Referring to FIG. 9, in the present disclosure, each chiral layer can be formed in a geometric pattern on a number of pixels. The material constituting the selective reflection layer of the chiral layer chiral LC is coated with a molecular structure capable of forming a chain in a photocurable (UV Curable) form and a predetermined rotational direction, and only the portion where blue selective reflection is desired (red pixel and green pixel) is exposed through an exposure mask, so that a Curable CLC layer for blue selective amplification can be formed only in the selective portion. Thereafter, the area where UV curing is not formed by blocking the mask pattern is washed away through a Develop process, so that a chiral layer can be formed only in the desired portion.

[0117] Additionally, each chiral layer can be formed through a UV curing structure and a UV curing pattern using a desired MASK. At this time, a chiral structure with a predetermined rotation direction can be formed at a position corresponding to R / G / B by adjusting the pitch by inducing a pitch change state according to temperature.

[0118] FIG. 10 is a drawing showing an example of the molecular structure of a chiral structure in another embodiment of the present disclosure.

[0119] Referring to FIG. 10, the material constituting the selective reflection layer of the chiral layer (200) (chiral LC) can be formed of a material including a molecular structure capable of forming a UV-curable chain. The material constituting the chiral layer (200) can include, for example, a monoacrylate or diacrylate molecular material having one or two acrylate reactive groups capable of being cured by UV. At this time, the molecular material has a bonding structure "R" composed of all various birefringences, and the molecule of R can include any one of all other reactive bonding structures including a phenyl group, a heagonal group, a methyl group, an ester group, an ether group, etc.

[0120] FIG. 11 is a diagram illustrating the pitch of liquid crystal molecules in a chiral layer in one embodiment of the present disclosure.

[0121] Referring to Figure 11, the liquid crystal molecules within the chiral layer can reflect light of different wavelengths depending on the length of the helical rotation structure.

[0122] Specifically, when the length of the helical rotation structure of a birefringent molecule changes, the reflected wavelength may change according to the de Vries condition Δλ = Δn p (Δλ: wavelength range of the selectively reflected expression color, Δn: difference in refractive index (n1-n2), p: rotation pitch repetition length).

[0123] Meanwhile, the rotational force per unit thickness of the chiral layer (d / p: d is the unit thickness of the chiral LC helical structure, p: the helical rotational twist repetition period of the CLC molecule) increases as the temperature increases. Therefore, by inducing a temperature change, the helical rotational twist repetition period of the CLC molecule can be controlled, and ultimately, the wavelength of the amplified light can be controlled.

[0124] Figure 12 is a graph showing the wavelength of light selectively reflected from a chiral liquid crystal depending on temperature.

[0125] Referring to Fig. 12, the color conversion layer can induce an effect of shortening the rotational pitch p in a CLC layer of unit thickness d at high temperatures. When a change in the direction of temperature increase (ΔT) is applied, the rotational length of the CLC liquid crystal is directly controlled through the continuous strengthening phenomenon of the rotational force of d / p. Ultimately, as the temperature increases, the chiral layer tends to adjust the selective reflection wavelength of the De Vries condition toward the blue wavelength side.

[0126] Figure 13 is a graph showing the change in pitch of a chiral structure according to temperature.

[0127] Referring to Figure 13, the chiral structure has high viscosity in the Smectic phase and low viscosity in the Nematic phase. As the temperature increases, the chiral structure transitions to the Nematic phase, lowering its viscosity and increasing its rotational force per unit length. Therefore, as the temperature increases, the pitch length of the chiral structure shortens.

[0128] Conversely, as the temperature decreases, the chiral structure undergoes a phase transition from the nematic phase to the smectic phase, and the pitch of the helical structure becomes longer.

[0129] Ultimately, the chiral structure is formed by the De Vires condition Δλ= Δn due to temperature change.

[0130] p (Δλ: wavelength range of the expression color to be selectively reflected, Δn: difference in refractive index (n1-n2), p: rotation pitch repetition length) can be adjusted.

[0131] Figure 14 is a conceptual diagram showing the optical path of a circularly polarized light emitting display device in one embodiment of the present disclosure.

[0132] Referring to Fig. 14, by adjusting the pitch (rotation length) in a chiral structure having a rotational direction, light of a specific wavelength can be selectively controlled according to colors such as red, green, and blue. If it is assumed that a right-handed chiral structure is formed in this process, 50% of the light emitted from the light emitting element (110) passes through the chiral layer (200) and polarizer (300) first as left circular polarization (Left CPL) and is emitted to the outside.

[0133] At this time, the emitted light is reflected while passing through the Right-Handed Chiral structure (200). The reflected 50% Right CPL returns to the OLED and is reflected like a mirror by the reflective electrode (110) inside the OLED. At this time, the reflected Right CPL is converted back into Left CPL. After that, the light converted into Left CPL passes through the chiral layer (200) and polarizer (300) having the Right-Handed Chiral structure for a second time to efficiently reinforce the existing light.

[0134] This process is repeated repeatedly, so that in addition to the original primary Left CPL, 50% of the light corresponding to the Red, Green, and Blue colors is converted to the Left CPL, ultimately achieving the ideal 100% Left CPL.

[0135] FIG. 15 is a conceptual diagram illustrating a variation of the pattern of a chiral layer (200) in another embodiment of the present disclosure.

[0136] Referring to Fig. 15, a chiral layer can be created by changing the temperature of one element to change several pitch lengths and fixing the memory by MASK patterning only the desired location. Therefore, the created display device can form chiral structures of various colors at once when restored to the operating condition temperature of room temperature. In addition, it can be created by changing the direction in which the first chiral layer (210), the second chiral layer (220), and the third chiral layer (230) are arranged.

[0137] FIG. 16 is a conceptual diagram illustrating another variation of the pattern of a chiral layer in another embodiment of the present disclosure.

[0138] Referring to Figure 16, in general, Blue < Red in the emission light of OLED<Green 로 빛의 효율이 차이가 나게 된다. 따라서 Blue > The pixel size of the light-emitting element can be configured differently in the order of Red > Green, and the size of the chiral layer (210, 220, 230) can be set differently. This enables the configuration of a photo pattern using light.

[0139] Figure 17 is a conceptual diagram showing the structure of a vertically stacked OLED (Tandem OLED).

[0140] Referring to FIG. 17, the chiral layer according to the present disclosure can be applied to a vertically stacked OLED other than the R / G / B separated light described above.

[0141] FIG. 18 is a graph illustrating a multilayer chiral layer and a half-wavelength in one embodiment of the present disclosure.

[0142] Referring to Fig. 18, a hetero-tandem structure can be formed by combining a chiral structure (P1) with a short itch length and a chiral pitch (P2) with a long itch length to form a short-wavelength chiral regression reflection (λ1) and a long-wavelength chiral regression reflection (λ2). Through this, a chiral reflection structure corresponding to the white region of the visible light region can be formed by combining a short-wavelength chiral regression reflection (λ1) and a long-wavelength chiral regression reflection (λ2).

[0143] FIG. 19 is a graph illustrating a multilayer chiral layer (200) and a half-wavelength in another embodiment of the present disclosure.

[0144] Referring to Fig. 19, in order to sufficiently secure and precisely configure the White characteristics in the entire visible light range, the heterochiral structure can be configured with three or more layers. For example, when configured with three layers, in addition to the short wavelength (λ1) formed by the short pitch (P1) and the long wavelength (λ2) formed by the long pitch (P2), an intermediate wavelength (λ3) formed by the intermediate pitch (P3) is added to form a White all-visible light reflective layer.

[0145] The order of stacking chiral layers (200) can be arbitrarily configured in various orders such as P1 / P2 / P3, P1 / P3 / P2, P2 / P1 / P3, P2 / P3 / P1, P3 / P2 / P1, P3 / P1 / P2, etc. If the number of chiral pitches is 3 or more, the stacking order of these can be arbitrarily selected by utilizing all combinations of P1, P2, P3, ..., Pn. In this way, optimal reflection characteristics can be implemented through various tandem chiral structures.

[0146] FIG. 20 is a conceptual diagram illustrating a molecular structure included in a chiral layer (200) in another embodiment of the present disclosure.

[0147] Referring to FIG. 20, the chiral material included in the chiral layer (200) in the present disclosure may be configured around a missing carbon atom represented by C*. Atoms with different electronegativity may be bonded around this C* atom, thereby creating a structure that does not form a symmetrical electronegativity configuration. Due to this structural characteristic, the chiral material may exhibit optical rotation properties. This rotation effect is a characteristic of a chiral compound, and at least one chiral compound must be present.

[0148] At this time, a chiral compound can have one of two types of rotational properties depending on the arrangement of atoms around the C* atom. That is, it can be a compound that includes a configuration that can have either a right-handed chiral or a left-handed chiral rotational property.

[0149] As described above, the circularly polarized light emitting display device according to the present disclosure blocks external light incident on the display and maximizes the light emission efficiency of light generated from the light emitting element (120).

Claims

1. Reflective electrode; Light-emitting element layer; Circular polarization layer; and A circularly polarized light-emitting display device comprising a selective reflection layer provided between the light-emitting element layer and the circularly polarized layer, at least a portion of which is configured in the same or opposite direction to the light transmission rotation direction of the circularly polarized layer.

2. In paragraph 1, The above selective reflection layer is a circularly polarized light-emitting display device in which the transmittance changes depending on the direction of rotation of the light.

3. In paragraph 2, A circularly polarized light-emitting display device in which the selective reflection layer has a twist rotation structure and includes a chiral optical structure having a pitch of tens to hundreds of nm in length.

4. In paragraph 3, The above chiral optical structure is a circularly polarized light emitting display device having an optical effect of rotating the incident light to the left or right.

5. In paragraph 4, The above chiral optical structure is a circular polarization light emitting display device including a helical optical rotation structure.

6. In paragraph 5, The above chiral optical structure is a circularly polarized light emitting display device which is a liquid crystal or mesognic molecule having a chiral molecule and a refractive index anisotropy (Δn).

7. In paragraph 6, The above selective reflective layer A circularly polarized light-emitting display device configured such that the reflection wavelength (Δλ-chiral) of the chiral optical structure is greater than or equal to the emission wavelength (Δλ-Emission) of the light-emitting element layer.

8. In paragraph 7, A circularly polarized light emitting display device in which the center wavelength position of the reflection wavelength width of the chiral optical structure includes a wavelength position within 200 nm to 2000 nm.

9. In paragraph 4, A circularly polarized light-emitting display device in which the above chiral optical structure is configured to reflect light corresponding to a chiral photonic band gap reflection wavelength.

10. In paragraph 9, The above chiral optical structure is, Among the unpolarized incident light generated from the light-emitting element layer, light in the first directional circular polarization state, which is the same as the rotation direction of the chiral optical structure, is reflected to the light-emitting element layer, A circularly polarized light-emitting display device having a first direction rotation structure that allows light in a second direction circularly polarized state opposite to the first direction to pass through.

11. In paragraph 10, A circularly polarized light-emitting display device in which the above circularly polarized layer has left circular polarization or right circular polarization characteristics to suppress reflection of external light, and is configured to have a linear polarizer and one or two optical retardations.

12. In paragraph 9, A circularly polarized light emitting display device having the second directional polarization characteristic so that the second directional polarized light that matches the circular polarization rotation of the circularly polarized layer can pass through the second directional polarization characteristic.

13. In paragraph 10, A circularly polarized light-emitting display device in which light in the first directional polarization state, which is the same as the rotational direction of the chiral optical structure, is reflected from the selective reflection layer, is reflected from the reflective electrode in the second directional polarization state, which is the circularly polarized state in the opposite direction of the rotation of the chiral optical structure.

14. In paragraph 13, A circularly polarized light emitting display device in which the light reflected in the second directional polarization state, which is a circularly polarized state opposite to the chiral optical structure and is the same as the rotational direction of the anti-reflection circularly polarized light in which the linear polarizer and the phase retardation layer are laminated, passes through the light emitting element layer, the selective reflection layer, and the circularly polarized light layer and is emitted.

15. In paragraph 14, A circularly polarized light-emitting display device in which the emission point of the first light generated from the light-emitting element layer is aligned with the polarization rotation direction of the anti-reflection layer of the circularly polarized light including the final linear polarizer and the phase delay layer by adding the second light reflected from the selective reflection layer and the reflection electrode (110) at different emission points, thereby improving the luminous efficiency of the light-emitting display without optical loss due to the polarizer.

16. In paragraph 15, A circularly polarized light-emitting display device in which the selective reflection layer comprises a chiral liquid crystal layer so that the refractive indices of n1 and n2 can appear in rotational repetition.

17. In paragraph 16, A circularly polarized light emitting display device manufactured through a process in which the chiral layer has left-handed chirality and / or right-handed chirality.

18. In paragraph 17, The above chiral layer is, It is configured so that the rotational force per unit length changes according to the temperature change of the above chiral structure, A circularly polarized light-emitting display device configured so that the wavelength of the reflected light becomes shorter or, conversely, longer as the temperature of the chiral structure increases.

19. In paragraph 18, A circularly polarized light-emitting display device comprising an organic, inorganic, inorganic-organic hybrid, quantum dot, perovskite, quantum nanowire, or organic light-emitting semiconductor, and having at least one polarizer.

20. In paragraph 16, A circularly polarized light-emitting display device in which the chiral layer is integrally formed with the light-emitting element layer.

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