KR101950379B1 - Viewing angle controllable display - Google Patents

Abstract

The present invention relates to a display device capable of controlling a viewing angle. The display device capable of controlling the viewing angle comprises: a display panel; A polarization switching unit configured to switch a polarization direction of incident light and mounted on a front surface of the display panel; And a polarization-dependent prism array film which is mounted on the front surface of the polarization switching unit so that on / off of the prism function is controlled according to the polarization direction of the incident light, thereby controlling the viewing angle distribution of the display panel. When the prism function of the polarization-dependent prism array film is turned on or off according to the polarization direction of the incident light, the display device displays the image on the viewing angle of the directional backlight unit constituting the display panel Or operates in a wide viewing angle mode by the polarization dependent prism array film.
The viewing angle controllable display device according to the present invention can control the viewing angle distribution of the display panel without losing the light efficiency by stacking the polarization dependent prism array film on the front surface of the display panel such as the LC panel or the OLED panel including the directional BLU do.

Description

A viewing angle controllable display,

The present invention relates to a viewing angle controllable display device, and more particularly, to a viewing angle controllable display device capable of controlling the viewing angle distribution of a display panel without losing a light efficiency by stacking a polarization dependent prism array film on a front surface of a display panel such as an LC panel or an OLED panel To a display device.

2. Description of the Related Art In recent years, the use of portable electronic devices such as mobile phones, tablet PCs, PDAs, and notebook computers has been rapidly increasing, and protection of privacy in public places has become a new challenge. In order to protect privacy when using portable electronic devices in such public places, display devices must have a narrow viewing angle.

However, when a plurality of users use the portable electronic device at the same time, or when one user uses the portable electronic device at an oblique angle instead of the frontal view, a display device having a narrow viewing angle has a problem of visibility. In this case, it is preferable that the display device has a wide viewing angle.

As described above, it is necessary for the display device of the portable electronic device to be able to switch between a narrow viewing angle (NVA) and a wide viewing angle (WVA) according to circumstances, Development of display devices has been demanded.

In liquid crystal displays, several approaches have been introduced to obtain the viewing angle distribution control characteristics between WVA and NVA. In most cases, a wide viewing angle LC mode such as IPS, MVA, PVA, FFS mode to control the gray level of each pixel, and a laminate structure using additional LC panels for viewing angle distribution control. FIG. 1 illustrates an IPS mode for gradation representation and a HAN mode stacking structure for viewing angle distribution control according to the prior art. The laminated structure of Fig. 1 is the contents published in Proc, SID'06, vol. 37, pp. 705-708.

Referring to FIG. 1, an LC panel is laminated for viewing angle distribution control, and an LC panel is used only for a viewing angle distribution control without a pixel pattern such as ECB, HAN, and VA modes. FIG. 1 (a) shows a state in which the LC panel is used in a wide viewing angle mode, and FIG. 1 (b) shows a state in which the LC panel is used in a narrow viewing angle mode.

In principle, the approaches according to the above-described method use a view angle dependent light absorption in the polarizer in order to realize a narrow viewing angle state without changing the incident light distribution. Accordingly, inevitably a large amount of light loss occurs in a narrow viewing angle mode. Also, due to the viewing angle asymmetry of the LC panel stacked for the viewing angle distribution control, the viewing angle distribution of the entire system has a problem of asymmetry.

Korean Patent Publication No. 10-2008-0092622 Korean Patent Publication No. 10-2006-0110678

An object of the present invention is to provide a display device capable of controlling the viewing angle distribution of a display panel without losing a light efficiency by laminating a polarization dependent prism array film on a front surface of a display panel such as an LC panel or an OLED panel .

According to an aspect of the present invention, there is provided a display device capable of controlling a viewing angle, including: a display panel for outputting light in a polarized state; A polarization switching unit configured to switch a polarization direction of incident light and mounted on a front surface of the display panel; And a polarization-dependent prism array film which is mounted on the front surface of the polarization switching unit so that on / off of the prism function is controlled in accordance with the polarization direction of the incident light, thereby controlling the viewing angle distribution of the display panel.

In the display device capable of controlling the viewing angle according to the first aspect, the display panel includes an LC panel (Liquid Crystal Panel) composed of two polarizers and a liquid crystal layer disposed therebetween, and a directional backlight unit (BLU) Or an OLED panel (Organic Light Emitting Diodes Panel), a directional optical film, and a polarizer.

In the display device capable of controlling the viewing angle according to the first aspect, the display device is characterized in that the prism function of the polarization-dependent prism array film is turned ON or OFF according to the polarization direction of the incident light, The light from the display panel operates in a narrow viewing angle mode in accordance with the viewing angle of the display panel formed by the light emitted from the display panel or the light from the display panel is refracted by the polarization dependent prism array film to operate in the wide viewing angle mode desirable.

In the display device capable of controlling the viewing angle according to the first aspect, the polarization-dependent prism array film may include a transparent substrate; An isotropic upper layer formed of a photocurable isotropic polymer material having a predetermined optical refractive index n _p and laminated on the substrate; And a birefringent layer made of a material having birefringence having a normal optical refractive index ( n _o ) and an extraordinary refractive index ( n _e ) and laminated on the isotropic upper layer, wherein the interface between the isotropic upper layer and the birefringent layer is a prism array It is preferable that the refractive index difference generated at the interface between the isotropic upper layer and the birefringent layer is different from each other according to the polarization direction of the incident light.

In the display device capable of controlling the viewing angle according to the first aspect, the isotropic upper layer is made of a photo-curable isotropic polymer material having a refractive index ( n _p ) equal to the normal refractive index of the birefringent layer, It is preferable to control the on / off of the function of the prism according to the polarization direction.

In the display device capable of controlling the viewing angle according to the first aspect, the refractive index n _p of the isotropic upper layer and the normal refractive index n _o and the extraordinary refractive index n _e of the birefringent layer satisfy n _p = n _o < n _e . &lt; / RTI &gt;

In the display device capable of controlling the viewing angle according to the first aspect, the birefringent layer is preferably made of a liquid crystal having birefringence or a photoactive liquid crystal polymer.

In the display device according to the first aspect, the polarizing-dependence prism array film may further include a lower alignment layer formed at an interface between the birefringent layer and the isotropic upper layer, and the material constituting the birefringent layer may be formed on the lower alignment layer In a single direction.

In the display device according to the first aspect, the polarization-dependent prism array film may further comprise an upper transparent substrate laminated on the surface of the birefringent layer, and an upper alignment layer is provided on one surface of the upper transparent substrate, And the material constituting the birefringent layer is oriented in a single direction by the upper alignment layer.

In the display device capable of controlling the viewing angle according to the first aspect, it is preferable that the prism formed at the interface between the isotropic upper layer and the birefringent layer has a triangular shape.

In the display device capable of controlling the viewing angle according to the first aspect, the polarization switching unit may include a liquid crystal layer; An upper alignment layer disposed on the upper portion of the liquid crystal layer; An upper transparent electrode layer positioned between the liquid crystal layer and the upper alignment layer; A lower orientation layer located below the liquid crystal layer; And a lower transparent electrode layer positioned between the liquid crystal layer and the lower alignment layer.

A display device capable of controlling a viewing angle according to a second aspect of the present invention includes: a directional backlight unit; A polarization-dependent prism array film mounted on a front surface of the directional backlight unit, the polarization-dependent prism array film configured to be partially refracted and partially straightened according to a polarization state of incident light provided from the directional backlight unit; A polarization switching unit mounted on a front surface of the polarization dependent prism array film so as to switch the polarization direction of incident light; And an LC (Liquid Crystal) panel composed of two polarizers and a liquid crystal layer disposed therebetween and mounted on a front surface of the polarization switching unit, so that the viewing angle distribution of the LC panel can be controlled.

In the above-described display device capable of controlling the viewing angle according to the second aspect, the polarization-dependent prism array film comprises: a transparent substrate; An isotropic upper layer formed of a photocurable isotropic polymer material having a predetermined optical refractive index n _p and laminated on the substrate; And a birefringent layer made of a material having a normal refractive index ( n _o ) and an extraordinary refractive index ( n _e ) and having birefringence and laminated on the isotropic upper layer; Wherein an interface between the isotropic upper layer and the birefringent layer is in the form of a prism array, incident light perpendicular to the alignment direction of the material constituting the birefringent layer is outputted straight without refraction, It is preferable that parallel incident light is refracted and output.

In the display device capable of controlling the viewing angle according to the second aspect, the polarization switching unit may include a liquid crystal layer; An upper alignment layer disposed on the upper portion of the liquid crystal layer; An upper transparent electrode layer positioned between the liquid crystal layer and the upper alignment layer; A lower orientation layer located below the liquid crystal layer; A lower transparent electrode layer positioned between the liquid crystal layer and the lower alignment layer; .

In the display device capable of controlling the viewing angle according to the second aspect, the display device has a linearly polarized state having a polarization state coinciding with the transmission axis of the polarizer of the LC panel in accordance with ON / OFF of the polarization switching part Of the liquid crystal panel is operated so as to operate in a narrow viewing angle mode or in a wide viewing angle mode by passing refracting light having a polarization state coinciding with the transmission axis of the polarizer of the LC panel,

The prism angle of the prism array formed at the interface between the isotropic upper layer and the birefringent layer is preferably determined according to a viewing angle required in the wide viewing angle mode.

In the display device according to the second aspect of the present invention, the isotropic upper layer is made of a photo-curable isotropic polymer material having a refractive index ( n _p ) equal to the normal refractive index of the birefringent layer, refractive index (n _p) and the ordinary ray refractive index of the birefringent layer (n _o) and extraordinary refractive index (n _e) of preferably has the relationship _{n p = n o <n e} .

The viewing angle controllable display device according to the present invention is a viewing angle controllable display device in which a polarization-dependent prism array film is laminated on a front surface of a display panel such as an LC panel or an OLED panel so that the viewing angle distribution of the display panel can be changed to a wide viewing angle mode or a narrow viewing angle mode It becomes possible to control.

FIG. 1 illustrates an IPS mode for gradation representation and a HAN mode stacking structure for viewing angle distribution control according to the prior art.
FIG. 2 is a schematic cross-sectional view of a display device capable of controlling a viewing angle according to a first preferred embodiment of the present invention.
FIG. 3 is a cross-sectional view illustrating a structure and operation of a polarization dependent prism array film in a display device capable of controlling a viewing angle according to a first preferred embodiment of the present invention.
4 is a conceptual diagram illustrating a principle of operation of a display device capable of controlling a viewing angle according to a first preferred embodiment of the present invention.
FIG. 5 is a flowchart sequentially illustrating a process of manufacturing a polarization dependent prism array film of a display device capable of controlling a viewing angle according to a first preferred embodiment of the present invention.
6 shows a chart of the luminance distribution in the polarization-dependent prism array film measured on the directional BLU in the display device capable of controlling the viewing angle according to the first preferred embodiment of the present invention.
FIG. 7 is a graph showing an angular luminance distribution according to a viewing angle in a polarization-dependent prism array film in a directional BLU at different voltage conditions in the x-axis direction, according to a first embodiment of the present invention; It is a graph.
8 is a graph showing a simulation result of a luminance distribution according to a viewing angle under various refractive condition conditions in a display device capable of controlling a viewing angle according to a first preferred embodiment of the present invention.
9 is a cross-sectional view illustrating a display device capable of controlling a viewing angle according to a second embodiment of the present invention.
10 is a cross-sectional view illustrating a display device capable of controlling a viewing angle according to a third embodiment of the present invention.

The viewing angle controllable display device according to the present invention can control the viewing angle distribution of the display panel without losing the light efficiency by stacking the polarization dependent prism array film on the front surface of the display panel such as the LC panel or the OLED panel including the directional BLU do.

&Lt; Embodiment 1 >

Hereinafter, a configuration and operation of a display device capable of controlling a viewing angle according to a first preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a schematic cross-sectional view of a display device capable of controlling a viewing angle according to a first preferred embodiment of the present invention.

Referring to FIG. 2, a display device 20 according to the present invention includes a display panel 17, a polarization switching unit 15 provided on the front surface of the display panel, and a polarization dependent prism array film 10 ).

2, the display panel 17 is formed by stacking a directional backlight unit 170 and an LC panel, and the LC panel includes two polarizers 172 and 174 and a polarizer 172 disposed between the polarizers And a liquid crystal layer 176. The two polarizers 172 and 174 are preferably composed of a polarizer 172 and an analyzer 174, respectively.

The polarization switching unit 15 is configured to switch the polarization direction of incident light and is mounted on the front surface of the LC panel. The polarization switching unit 15 includes a liquid crystal layer 150, upper and lower alignment layers 152 and 154 disposed at upper and lower portions of the liquid crystal layer, An upper transparent electrode layer 153, and a lower transparent electrode layer 155 positioned between the liquid crystal layer and the lower alignment layer. In the polarization switching part having the above-described configuration, the alignment direction of the liquid crystal layer is changed in accordance with the driving voltage applied from the outside, and as a result, the polarization direction of the incident light can be changed.

The polarized-light-dependent prism array film 10 is mounted on the front surface of the polarization switching unit so that on / off of the prism function is controlled according to the polarization direction of the incident light. When the prism function of the polarization dependent prism array film is turned off, the light passing through the polarization dependent prism array film goes straight, and the narrow viewing angle mode corresponding to the viewing angle of the directional backlight unit . In addition, when the prism function of the polarization-dependent prism array film is turned ON, the display device capable of controlling the viewing angle according to the present invention is capable of controlling the angle of incidence of light by the polarization-dependent prism array film And operates in a viewing angle mode. Therefore, in the display device according to the present invention, the viewing angle in the narrow viewing angle mode is determined by the viewing angle of the directional backlight unit, and the viewing angle in the wide viewing angle mode is set at the interface between the isotropic upper layer and the birefringent layer in the polarization- Is determined by the prism angle of the prism to be formed.

On the other hand, in another embodiment of the viewing angle controllable display device according to the first embodiment of the present invention, by reversely orienting the orientation direction of the polarization dependent prism array film, when the prism function is turned on, it operates in a narrow viewing angle mode, It may be configured to operate in the wide viewing angle mode.

FIG. 3 is a cross-sectional view illustrating a structure and operation of a polarization dependent prism array film in a display device capable of controlling a viewing angle according to a first preferred embodiment of the present invention. Hereinafter, the structure and operation of the polarization dependent prism array film will be described in detail with reference to FIG.

The polarization dependent prism array film 10 includes a transparent substrate 100, an isotropic upper layer 110, and a birefringent layer 120. In the polarization dependent prism array film (10) according to the present invention, the interface between the isotropic upper layer and the birefringent layer is formed in the shape of a prism array, and is generated at the interface between the isotropic upper layer and the birefringent layer Are different from each other in accordance with the polarization direction of the incident light.

The isotropic upper layer 110 is formed of a photocurable isotropic polymer material having a predetermined optical refractive index n _p and is stacked on the substrate.

The birefringent layer 120 is made of a birefringent material having a normal optical refractive index (n _o ) and an extraordinary refractive index (n _e ), and is stacked on the isotropic upper layer. Preferably, the interface between the isotropic upper layer and the birefringent layer has a triangular prism shape, and may be realized in the form of a prism array. The prism is formed of a triangular shape made up of inclined at a predetermined angle of the prism _(prism θ) inclined with respect to the planar exit surface, is arranged to repeat these prisms it is to implement the prism array pattern.

The birefringent layer is preferably made of a liquid crystal (LC) or a photocurable liquid crystal polymer (Reactive Mesogen) material having birefringence aligned in a single direction.

In order to align the liquid crystalline material or the photo-curable liquid crystalline polymer material constituting the birefringent layer in a unidirectional direction, the polarization-dependent prism array film 10 may have a structure in which the lower orientation layer 110 is formed on the interface between the isotropic upper layer 110 and the birefringent layer 120, (Not shown) to orient the medium of the birefringent layer in a bottom-up manner or to further include an upper orientation layer (not shown in the figure) on the upper surface of the birefringent layer 120, the birefringent layer 120 may be oriented in a bottom-up manner or a top-down manner by orienting the medium of the birefringent layer 120 in the down-type or the upper and lower orientation layers on the upper and lower surfaces of the birefringent layer 120, It can be oriented in a single direction. By the upper orientation layer and / or the lower orientation layer, the medium constituting the birefringent layer is oriented in a single direction.

Dependent prism array film according to the present invention is characterized in that the refractive index n _p of the isotropic upper layer 110 and the normal refractive index n _{o which} is a refractive index in a direction perpendicular to the alignment direction of the birefringent layer 120, It is preferable that the on / off of the prism function can be controlled in accordance with the polarization direction of the incident light by setting the relationship of n _o = n _{p &} lt; n _e to the ideal light refractive index ( n _e )

Referring to FIG. 3A, when the linearly polarized light is incident on the polarization dependent prism array film according to the present embodiment, when the polarization direction of the incident light is perpendicular to the alignment direction of the birefringent layer 120, The birefringent layer 120 has a refractive index of n _o , and since n _o = n _p , the incident light goes straight without refraction. As a result, the polarization-dependent prism array film according to this embodiment does not operate as a prism when light having a polarization direction perpendicular to the alignment direction of the birefringent layer is incident.

Referring to FIG. 3 (b), when the linearly polarized light is incident on the polarization dependent prism array film according to the present embodiment, the polarization direction of the incident light coincides with the alignment direction of the birefringent layer 120 case, the birefringent layer 120 is to have a refractive index n _e, the light is incident, so _p n <n _e is represented by a refractive index difference at the interface between the isotropic upper layer 110 and the birefringent layer (120). As a result, when the light having the polarization direction coinciding with the alignment direction of the birefringent layer is incident, the polarization dependent prism array film according to the present embodiment operates as a prism array, and the incident light spreads. Therefore, when the polarization direction of the incident light is perpendicular to the alignment direction of the birefringent layer, the prism function is turned off. When the polarization direction of the incident light matches the alignment direction of the birefringent layer, do.

In the display device capable of controlling the viewing angle according to the first embodiment of the present invention, when the prism function of the polarization dependent prism array film is turned ON, the polarization dependent prism array film operates in the wide viewing angle mode, the prism angle of the prism array is formed at the interface between the isotropic upper layer and the birefringent layer (θ _prism) is preferably determined in accordance with the field of view required in the wide viewing angle mode. As the prism angle increases, the viewing angle increases. Here, the prism angle (θ _prism), as shown in Fig 3, means the angle with the inclined surface of the prism on a plane parallel to the exit surface of the prism.

Hereinafter, with reference to FIG. 4, the principle of operation of a display device capable of controlling a viewing angle according to a first preferred embodiment of the present invention will be described in detail. 4 is a conceptual diagram illustrating a principle of operation of a display device capable of controlling a viewing angle according to a first preferred embodiment of the present invention.

4A, when the polarization state of the incident light is parallel to the alignment direction of the birefringent layer 120, the incident light passes through the prism array film 10 without refraction, and finally, the narrow The beam distribution results in a narrow viewing angle mode.

Referring to FIG. 4B, when the polarization state of the incident light is perpendicular to the alignment direction of the birefringent layer 120, incident light is refracted at the interface between the birefringent layer 120 and the isotropic upper layer 110, .

The display device according to the present invention having the above-described configuration can electrically control the polarization angle of the light incident on the liquid crystal layer of the polarization switching part 15, and the viewing angle distribution can be narrowed without loss of light efficiency, It is possible to continuously switch from the viewing angle state to the wide viewing angle state. In the drawings of the present invention, only the TN mode of the liquid crystal is displayed, but the present invention is also applicable to the VA, ECB, OCB, IPS, and FFS modes.

The display device having the above-described configuration can be fabricated as an integral unit through the direct imprinting process on the polarization switching unit or by combining the polarization switching prism array with the polarization dependent prism array on the film or glass substrate. Hereinafter, a process of manufacturing the polarization dependent prism array film of the display device capable of controlling the viewing angle according to the present invention will be described with reference to FIG. FIG. 5 is a flowchart sequentially illustrating a process of manufacturing a polarization-dependent prism array film of a display device capable of controlling a viewing angle according to the present invention.

The method of manufacturing a polarization-dependent prism array film according to the present invention comprises the steps of depositing a photocurable isotropic polymer material 710 on a lower transparent substrate 700 and then forming a prism array template 750 (step a). Next, the photocurable isotropic polymer materials 710 are cured (step b) by irradiating with UV light, and the prism array template 750 is separated and removed (step c). As a result, by using the imprinting process An isotropic upper layer 710 'in the shape of a prism array is completed on the lower transparent substrate 700. [

Next, before the alignment material is applied to the surface of the isotropic upper layer 710 ', the surface of the isotropic upper layer 710' is subjected to UVO treatment to hydrophilize the surface of the isotropic upper layer 710 " It is desirable to improve the coating properties of the material (step d).

Next, an alignment material 730 is applied to the surface of the isotropic upper layer 710 " (step e), and rubbed in a single direction to form a lower part for the bottom-up alignment on the surface of the isotropic upper layer 710 & Thereby forming an alignment film 730 '(step f). Polyvinylachol (PVA) may be used as the alignment material.

Next, an alignment material is applied on the upper transparent substrate 770 and rubbed to manufacture an upper transparent substrate 770 having an upper alignment film 780 for top-down alignment (step g).

Next, the upper transparent substrate 770 is disposed on the lower alignment film 730 'on the lower transparent substrate 700, and the upper alignment film 730' is formed between the lower alignment film 730 'and the upper alignment film 780, After the liquid crystalline polymer material 720 is injected (step h), the photo-curable liquid crystalline polymer material 720 is photo-cured by UV irradiation to form a birefringent layer 720 '(step i). The photo-curable liquid crystalline polymer material 720 constituting the birefringent layer is aligned in a single direction according to the orientation effect by the lower alignment layer 730 'and the upper alignment layer 780. Next, the upper transparent substrate 770 and the upper alignment film 780 are separated from the birefringent layer 720 '(step j) to complete the polarization dependent prism array film according to the present invention.

In the above-described manufacturing process, step j, which is the last step, may be omitted so that the upper transparent substrate 770 and the upper alignment film 780 may not be removed as needed to complete the polarization dependent prism array film.

A display device capable of controlling the viewing angle according to the present invention was manufactured according to the above-described manufacturing process and various characteristics were analyzed. In the production process of the above-mentioned viewing angle control a display device capable of, during the imprinting process and a period of 18.5 ㎛ prism array using a template, and a height 11㎛, the prism angle (θ _prism) is 50 degrees, the photo-curable polymer isotropic phase The material is Norland Products. Was used Inc.'s n _p = 1.51 NOA89 the product, the photo-curable liquid crystalline polymeric substance constituting the birefringent layer were used RMM727 Merck's product, the liquid crystal layer portions polarization switching was used to E7 Merck's product, the liquid crystal Was 10 mu m, and the viewing angle of the directional BLU was 30 degrees.

6 shows a chart of the luminance distribution in the polarization-dependent prism array film measured on the directional BLU in the display device capable of controlling the viewing angle according to the first embodiment of the present invention. The equipment used for the viewing angle measurement of FIG. 6 is DMS 803 from Autronic-Melchers GmbH, and the alignment direction of the prism or birefringent layer is in the y-axis direction of 90 degrees.

6 (a), when Va = 0 V is applied to the TN liquid crystal layer and the TN liquid crystal layer is in the field off state, the incident polarized state becomes perpendicular to the orientation axis of the birefringent layer ( n _o = n _p ), Resulting in narrow viewing angle characteristics.

Referring to FIG. 6 (b), when a field of Va = 5 V is applied to the TN liquid crystal layer, incident light from the directional BLU is incident on a refractive index mismatch condition ( n _e ≠ n _p ), It is refracted at the inclined interface of the birefringent layer and the isotropic upper layer. As a result, the luminance in the front direction decreases and the luminance in the viewing angle direction increases.

7 shows an angular luminance distribution according to a viewing angle in a polarization-dependent prism array film in a directional BLU under different voltage conditions in the x-axis direction in a viewing angle controllable display device according to the first embodiment of the present invention Graph.

Referring to FIG. 7, the viewing angle distribution of the polarization-dependent prism array film in the directional BLU is observed at different voltage conditions (Va = 0, 1.5, 1.8, 2.15, 5 V) at φ = 0 . It can be seen from Fig. 7 that as the applied voltage of the TN liquid crystal layer of the polarization switching section increases, the luminance in the front direction direction gradually decreases while the luminance in the viewing angle direction gradually increases. Also, it can be seen that, under all applied voltage conditions, the luminance distribution is symmetrical with respect to the viewing angle change. In addition, when calculating the total luminance by integrating the luminance distribution in the luminance distribution obtained under the respective voltage conditions, it can be seen that the total luminance is almost the same within the variation of 1.5%. This result means that the viewing angle controllable display device according to the present invention can continuously control the viewing angle without loss of light by using the lamination structure of the polarization dependent prism array film, the polarization switching part, and the directional BLU.

In the display device capable of controlling the viewing angle according to the first embodiment of the present invention, the refraction angle of the incident light is related to the angle of the prism structure and the refractive index difference at the interface between the birefringent layer and the isotropic upper layer. Considering these factors, we used the Breault Research Organization. Optical simulation was performed using optical modeling software of Advanced System Analysis Program (ASAPTM) Inc.

8 is a graph showing a simulation result of a luminance distribution according to a viewing angle in various refractive condition conditions in a display device capable of controlling the viewing angle according to the first embodiment of the present invention.

8 (a) shows the refractive indices of the birefringent layer and the isotropic upper layer are n _e = 1.65 and n _o = 1.51, the angular luminance distribution according to the viewing angles was simulated for different prism angle conditions of 40 °, 50 ° and 60 °. Referring to FIG. 8 (a), simulation results show that as the prism angle increases, the viewing angle distribution becomes wider and the front brightness decreases. It can also be seen that a wider field of view angle condition can be provided when the prism angle is 60 DEG as compared with the experimental conditions where the prism angle is 50 DEG.

FIG. 8 (b) shows the refractive index n _e = 1.55, 1.65, 1.75, and n _o = 1.51, the angular luminance distribution according to the viewing angle was simulated. The prism angle condition at this time was fixed at 50 °. Referring to FIG. 8 (b), the n _e As the value increases. It can be seen that the viewing angle is widened due to the increased refraction effect at the interface between the birefringent layer and the isotropic upper layer.

8 (c), in order to obtain a wider viewing angle condition, the birefringent layer is formed of n _e = 1.75, and the angular luminance distribution according to the viewing angle was simulated while varying the prism angle conditions at 40, 50 and 60 degrees. Referring to FIG. 8 (c), n _e It can be seen that each luminance distribution is wider in the same prism condition as compared with FIG. 8 (a). In particular, under the experimental conditions in which the prism angle is 60 degrees, the luminance in the direction of the viewing angle .

&Lt; Embodiment 2 >

Hereinafter, the configuration and operation of a display device capable of controlling a viewing angle according to a second embodiment of the present invention will be described in detail with reference to the accompanying drawings. The display device capable of controlling the viewing angle according to the second embodiment of the present invention is characterized by being applied to an OLED (Organic Light Emitting Diodes) panel.

9 is a schematic cross-sectional view illustrating a display device capable of controlling a viewing angle according to a second embodiment of the present invention. 9, the display device 8 according to the second embodiment of the present invention includes a display panel 87, a polarization switching part 85 provided on the front surface of the display panel, And a prism array film (80). The polarization switching portion 85 and the polarization dependent prism array film 80 according to the present embodiment are the same as those of the first embodiment.

The display panel 87 is composed of an OLED panel 870, a directional optical film 872 and a polarizer 874 as shown in FIG.

The display device according to the second embodiment having the above-described configuration operates in the same manner as the display device according to the first embodiment. Therefore, when the prism function of the polarization-dependent prism array film is turned off, the display device capable of controlling the viewing angle according to the second embodiment of the present invention, when the light passing through the polarization-dependent prism array film goes straight, A narrow viewing angle mode according to the viewing angle of the display device. When the prism function of the polarization-dependent prism array film is turned on, the display device capable of controlling the viewing angle according to the second embodiment of the present invention, when the light passing through the polarization-dependent prism array film is refracted, And operates in the wide viewing angle mode by the array film. Therefore, in the display device according to the present invention, the viewing angle in the narrow viewing angle mode is determined by the viewing angle of the directional optical film, and the viewing angle in the wide viewing angle mode is set at the interface between the isotropic upper layer and the birefringent layer in the polarization- Is determined by the prism angle of the prism to be formed.

On the other hand, in another embodiment of the viewing angle controllable display device according to the second embodiment of the present invention, when the prism function is turned on by operating the polarization direction-dependent prism array film in the opposite direction, It may be configured to operate in the wide viewing angle mode.

&Lt; Third Embodiment >

Hereinafter, a configuration and operation of a display device capable of controlling a viewing angle according to a third embodiment of the present invention will be described in detail with reference to the accompanying drawings.

10 is a schematic cross-sectional view of a display device capable of controlling a viewing angle according to a third embodiment of the present invention. 10, the display device 9 according to the third embodiment of the present invention includes a directional backlight unit 96, a polarization-dependent prism array film 90 provided on the front surface of the directional backlight unit 90, A polarization switching part 95 provided on the front surface of the film, and an LC panel 97 provided on the front surface of the polarization switching part. The configurations of the polarization switching part 95 and the polarization dependent prism array film 90 according to the present embodiment are the same as those of the first embodiment.

The LC panel 97 consists of two polarizers 972 and 974 and a liquid crystal layer 976 interposed therebetween as shown in Fig. 10, which has the same structure as the LC panel of the first embodiment .

The non-polarized light emitted from the directional backlight unit 96 is partially refracted by the birefringent layer of the polarization-dependent prism array film 90 and the other is straightened. In the direction parallel to the alignment direction of the material constituting the birefringent layer The polarized light is refracted and the polarized light in a direction perpendicular to the alignment direction of the material constituting the birefringent layer goes straight without refraction.

Referring to FIG. 9A, when the polarization switching unit 95 is off, the polarization state of the light advancing and refracted is rotated by 90 degrees, and the polarizer 972 Passing through only the straight-going light representing the state of polarization that coincides with the transmission axis of the light. As a result, it operates in a narrow viewing angle mode according to the viewing angle of the directional backlight unit.

Referring to FIG. 9B, when the polarization switching unit 95 is on, no polarization change appears in both straight and refracted light, and the polarization of the polarizer 972 of the LC panel Only the refracted light representing the polarization state coinciding with the transmission axis passes through. As a result, the light is refracted by the polarization dependent prism array film to operate in the wide viewing angle mode.

On the other hand, in another embodiment of the display device capable of controlling the viewing angle according to the third embodiment of the present invention, by reversely orienting the orientation direction of the polarization-dependent prism array film, when the polarization switching section is turned on, it operates in a narrow viewing angle mode, And may be configured to operate in the wide viewing angle mode when the addition is off.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be understood that various changes and modifications may be made without departing from the scope of the present invention. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

20, 8, 9: Display device
10, 80, 90: Polarization-dependent prism array film
15, 85, 95: polarization switching unit
17, 87: Display panel
150: liquid crystal layer
152: upper alignment layer
154: Lower alignment layer
153: upper transparent electrode layer
155: lower transparent electrode layer
100: Substrate of transparent material
110: isotropic upper layer
120: birefringent layer

Claims (17)

A display panel for outputting light in a polarized state;
A polarization switching unit configured to switch a polarization direction of incident light and mounted on a front surface of the display panel; And
A polarization-dependent prism array film which is mounted on a front surface of the polarization switching unit so that on / off of the prism function is controlled according to the polarization direction of the incident light;
So that the viewing angle distribution of the display panel can be controlled,
The display panel includes:
An LC panel (Liquid Crystal Panel) composed of two polarizers and a liquid crystal layer disposed therebetween, and a directional backlight unit (BLU) are laminated,
An OLED panel (Organic Light Emitting Diodes Panel), a directional optical film, and a polarizer,
The polarizing-dependence prism array film is characterized in that,
A transparent substrate;
An isotropic upper layer formed of a photocurable isotropic polymer material having a predetermined optical refractive index n _p and laminated on the substrate; And
A birefringent layer made of a material having a normal refractive index ( n _o ) and an extraordinary refractive index ( n _e ) and having birefringence and laminated on the isotropic upper layer;
And an interface between the isotropic upper layer and the birefringent layer is formed in the shape of a prism array. The refractive index difference generated at the interface between the isotropic upper layer and the birefringent layer is different from each other according to the polarization direction of the incident light A display device capable of controlling the viewing angle. delete The display device according to claim 1,
The ON / OFF of the prism function of the polarization dependent prism array film is determined according to the polarization direction of the incident light, and the light emitted from the display panel is linearly formed on / Wherein the display device is operated in a narrow viewing angle mode according to the viewing angle or the light emitted from the display panel is refracted by the polarization dependent prism array film to operate in the wide viewing angle mode. delete The display device according to claim 1,
Depending on the ON / OFF state of the prism function of the polarization-dependent prism array film, the light emitted from the display panel may be operated in a narrow viewing angle mode according to the viewing angle of the display panel formed by straightening the light emitted from the display panel, Dependent prism array film to operate in a wide viewing angle mode,
Wherein the prism angle of the prism array formed at the interface between the isotropic upper layer and the birefringent layer is determined according to a viewing angle required in the wide viewing angle mode. The prism of claim 1, wherein the isotropic upper layer is made of a photo-curable isotropic polymer material having a refractive index ( n _p ) equal to the normal refractive index of the birefringent layer, / OFF of the display device. The optical element according to claim 1, wherein the refractive index ( n _p ) of the isotropic upper layer and the normal optical refractive index ( n _o ) of the birefringent layer and the extraordinary optical refractive index ( n _e ) have a relationship of n _p = n _o < n _e A display device capable of controlling the viewing angle. The display device according to claim 1, wherein the birefringent layer is made of a liquid crystal having birefringence or a photoactive liquid crystal polymer. The prism array film according to claim 1, wherein the polarization-dependent prism array film further comprises a lower alignment layer formed at an interface between the birefringent layer and the isotropic upper layer,
Wherein the material constituting the birefringent layer is oriented in a single direction by the lower alignment layer. The prism array film according to claim 1, wherein the polarization-dependent prism array film further comprises an upper transparent substrate laminated on the surface of the birefringent layer,
An upper alignment layer is formed on one surface of the upper transparent substrate contacting the birefringent layer,
Wherein the material constituting the birefringent layer is oriented in a single direction by the upper alignment layer. The display device according to claim 1, wherein the prism formed at the interface between the isotropic upper layer and the birefringent layer has a triangular shape. The apparatus of claim 1, wherein the polarization switching unit comprises:
A liquid crystal layer;
An upper alignment layer disposed on the upper portion of the liquid crystal layer;
An upper transparent electrode layer positioned between the liquid crystal layer and the upper alignment layer;
A lower orientation layer located below the liquid crystal layer; And
A lower transparent electrode layer positioned between the liquid crystal layer and the lower alignment layer;
Wherein the display device is a display device. A directional backlight unit;
A polarization-dependent prism array film mounted on a front surface of the directional backlight unit, the polarization-dependent prism array film configured to be partially refracted and partially straightened according to a polarization state of incident light provided from the directional backlight unit;
A polarization switching unit mounted on a front surface of the polarization dependent prism array film so as to switch the polarization direction of incident light; And
An LC (Liquid Crystal) panel composed of two polarizers and a liquid crystal layer interposed therebetween, and mounted on a front surface of the polarization switching unit;
So that the viewing angle distribution of the LC panel can be controlled,
The polarizing-dependence prism array film is characterized in that,
A transparent substrate;
An isotropic upper layer formed of a photocurable isotropic polymer material having a predetermined optical refractive index n _p and laminated on the substrate; And
A birefringent layer made of a material having a normal refractive index ( n _o ) and an extraordinary refractive index ( n _e ) and having birefringence and laminated on the isotropic upper layer;
And an interface between the isotropic upper layer and the birefringent layer is formed in the shape of a prism array,
Wherein the incident light perpendicular to the alignment direction of the material constituting the birefringent layer is output without being refracted and outputted, and the incident light parallel to the alignment direction is refracted and output. delete 14. The polarization beam splitter of claim 13,
A liquid crystal layer;
An upper alignment layer disposed on the upper portion of the liquid crystal layer;
An upper transparent electrode layer positioned between the liquid crystal layer and the upper alignment layer;
A lower orientation layer located below the liquid crystal layer; And
A lower transparent electrode layer positioned between the liquid crystal layer and the lower alignment layer;
Wherein the display device is a display device. 14. The display device according to claim 13,
The linearly polarized light having the polarization state coinciding with the transmission axis of the polarizer of the LC panel passes through the ON / OFF state of the polarization switching unit to operate in a narrow viewing angle mode, or the transmission axis of the polarizer of the LC panel Refractive-index light having a coincident polarization state is transmitted to operate in a wide viewing angle mode,
Wherein the prism angle of the prism array formed at the interface between the isotropic upper layer and the birefringent layer is determined according to a viewing angle required in the wide viewing angle mode. 14. The birefringent optical element according to claim 13, wherein the isotropic upper layer is made of a photo-curable isotropic polymer material having a refractive index ( n _p ) equal to a normal refractive index of the birefringent layer,
The refractive index of the isotropic upper layer (n _p) and the ordinary ray refractive index of the birefringent layer (n _o) and extraordinary refractive index (n _e) the viewing angle-controllable display device, characterized in that a relationship of _{n p = n o <n e} .

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