Display device

Abstract

One embodiment of a display device includes a display unit, a light guide plate disposed below the display unit, a first light source unit disposed on one side of the light guide plate and irradiating light toward the light guide plate, and a second light source unit disposed below the light guide plate and irradiating light toward the light guide plate, wherein the light guide plate includes a plurality of emission surface patterns, the plurality of emission surface patterns are formed to protrude from the upper surface from which light is emitted, the longitudinal direction of each of the plurality of emission surface patterns is a first direction, and the plurality of emission surface patterns are arranged to be separated from each other in a second direction that intersects the first direction.

Description

Technical Field

[0001] This specification relates to a display device, and more particularly to a display device provided inside a vehicle.

Background Art

[0002] The content described herein merely provides background information for this specification and does not constitute prior art.

[0003] Entering the full-fledged information age, the field of display devices that visually display electrical information signals has been rapidly developing, and research has been continuously conducted to improve the performance of various display devices, such as thinning, lightening, and reducing power consumption.

[0004] These display devices include liquid crystal display devices (LCD), quantum dot display panel devices (QD), field emission display devices (FED), electro-wetting display devices (EWD), and organic light emitting display devices (OLED), etc.

[0005] Display devices have been miniaturized and developed to be portable by users or attached to mobile devices such as vehicles, and have been improved to be more conveniently utilized by users.

[0006] Also, display devices have been continuously improved to increase the resolution and brightness of the screen and provide clear images to users.

Summary of the Invention

Problems to be Solved by the Invention

[0007] The embodiments of this specification can provide a display device equipped with a light guide plate having a structure that can suppress the searchlight effect.

[0008] Furthermore, the embodiments described herein can provide a method for easily manufacturing a light guide plate and a display device equipped with a light guide plate manufactured by these methods.

[0009] The examples described herein can solve a variety of problems in addition to those mentioned. [Means for solving the problem]

[0010] One embodiment of a display device includes a display unit, a light guide plate disposed below the display unit, a first light source unit disposed on one side of the light guide plate and irradiating light toward the light guide plate, and a second light source unit disposed below the light guide plate and irradiating light toward the light guide plate, wherein the light guide plate includes a plurality of emission surface patterns, the plurality of emission surface patterns are formed to protrude from the upper surface from which light is emitted, the length direction of each of the plurality of emission surface patterns is a first direction, the plurality of emission surface patterns are arranged to separate from each other in a second direction intersecting the first direction, and the width of each of the plurality of emission surface patterns may increase as the plurality of emission surface patterns move toward the first light source unit.

[0011] The shape of the cross-section obtained by cutting the emission surface pattern in the second direction may be a semicircular or semielliptical shape that protrudes convexly from the upper surface of the light guide plate.

[0012] The light guide plate includes a first region where an emission surface pattern is formed, and a second region located on one side of the first region where an emission surface pattern is formed. The width of the emission surface pattern in the first region is formed to be smaller than the width of the emission surface pattern in the second region, and the emission surface pattern in the second region may be configured to have a continuously increasing width as it approaches the first light source.

[0013] The exit surface pattern is formed by injection molding using a mold, and the mold may be pressurized with a pressurizing tool so that forming grooves for each of the multiple exit surface patterns are defined in the mold.

[0014] The pressurizing tool may be configured to advance continuously in a first direction relative to the mold, creating a forming groove, and the depth of contact with the mold may change as it advances in the first direction.

[0015] The pressurizing tool can contact the mold at a depth corresponding to the first region of the mold, but at a depth smaller than that corresponding to the second region.

[0016] The pressurizing tool may be configured such that, at a position corresponding to the second region, the contact depth with the mold continuously increases as it advances in the direction corresponding to the first light source.

[0017] The light guide plate may include a bottom pattern positioned on its lower surface so as to protrude toward the second light source, and a side pattern positioned on its side so as to protrude toward the first light source.

[0018] The bottom surface pattern is formed in a pyramidal shape, and the area of ​​the first surface facing the first light source may be larger than the area of ​​the second surface facing the opposite direction from the first light source.

[0019] The longitudinal direction of the side pattern is the second direction, and the side pattern may include multiple side patterns, which may be arranged to be spaced apart from each other in a third direction that intersects the first and second directions.

[0020] The cross-sectional shape obtained by cutting the side pattern in the third direction is a semicircular or semi-elliptical shape that protrudes convexly from the side of the light guide plate, and the side pattern may have a constant width along the second direction.

[0021] The display unit includes a shared area where all users in front of the display unit can view the displayed image, and a variable personal area where the displayed image can be selectively viewed only by all users or some users. The shared area may at least partially overlap with the first area, and the variable personal area may at least partially overlap with the second area.

[0022] When the first light source unit is in the on state, all users can view the image displayed on the variable personal area. When the first light source unit is in the off state, the image displayed on the variable personal area may be configured such that only some users can view it.

[0023] The display unit may include a display panel on which an image is reproduced, a cover member disposed above the display panel, and an optical sheet disposed below the display panel and into which light passing through the light guide plate is incident.

[0024] An embodiment of the display device may include a light control film disposed below the light guide plate, an optical member disposed between the light control film and the second light source unit, and a reflector disposed below the second light source unit.

Advantages of the Invention

[0025] In the display device according to this specification, the upper surface of the light guide plate is formed such that the change in concavity and convexity is large and deep in the second direction. As a result, the light emitted from the upper surface of the light guide plate undergoes significant scattering, refraction, diffraction, total surface reflection, etc. in the second direction, significantly suppressing the searchlight phenomenon and making the luminance of the light emitted from the light guide plate uniform.

[0026] Also, in the display device according to this specification, the emission surface pattern may be configured such that the width increases as it approaches the first light source unit.

[0027] With such a structure, in a portion adjacent to the first light source portion where the searchlight phenomenon on the upper surface of the light guide plate is prominent, concavities and convexities are deeply formed in the second direction by the exit surface pattern, and the searchlight phenomenon can be effectively removed.

[0028] On the other hand, in a portion far from the first light source portion where the searchlight phenomenon on the upper surface of the light guide plate is weak, concavities and convexities are shallowly formed in the second direction by the exit surface pattern, and the luminance of the light emitted from the light guide plate can be increased.

[0029] Further, in manufacturing the light guide plate described in this specification, by continuously moving the pressing tool in the first direction with respect to the mold and changing the depth at which the pressing tool and the mold come into contact according to each region, formation grooves having different depths in the first direction can be manufactured. Also, with these methods, the manufacturing of one formation groove can be completed in one movement.

[0030] Therefore, in order to manufacture formation grooves having different depths in the first direction, there is no need to separately cut each part of the mold with a separate cutting tool, so the mold can be easily manufactured, the manufacturing time of the light guide plate can be shortened, and the manufacturing cost can be effectively saved.

[0031] Also, since the mold is not cut using a separate cutting tool, processing defects of the mold due to cutting can be reduced, and the overall manufacturing cost of the mold can be reduced.

[0032] The above-described effects and the specific effects of the present invention will be described and described while explaining the embodiments for implementing the following invention.

Brief Description of the Drawings

[0033] [Figure 1] It is a schematic cross-sectional view of a display device according to an embodiment. [Figure 2] It is a diagram for explaining the searchlight phenomenon occurring in the light guide plate. [Figure 3] It is a perspective view of a light guide plate according to an embodiment. [Figure 4] It is a view of FIG. 3 seen from another direction. [Figure 5] This is a plan view of a light guide plate according to one embodiment. [Figure 6] This is a front view of a light guide plate according to one embodiment. [Figure 7] This figure shows a portion of the bottom surface of a light guide plate according to one embodiment. [Figure 8] This is a magnified view of a portion of Figure 6. [Figure 9] This is a view of the right side of Figure 6. [Figure 10] This is a schematic diagram showing the mold and pressurizing tool. [Figure 11] This is a front view of a light guide plate according to one embodiment. [Figure 12] This is a cross-sectional view of the mold at point A, which corresponds to the point shown on the light guide plate in Figure 11. [Figure 13] This is a cross-sectional view of the mold at point B, which corresponds to the point shown on the light guide plate in Figure 11. [Figure 14] This is a cross-sectional view of the mold at point C, which corresponds to the point shown on the light guide plate in Figure 11. [Modes for carrying out the invention]

[0034] The aforementioned objectives, features, and advantages will be described in detail below with reference to the accompanying drawings, so that a person with ordinary skill in the art to which this specification belongs can easily implement the technical concept of this specification. In describing this specification, if a specific description of known technology relating to this specification is deemed to obscure the gist of this specification, the detailed description will be omitted. Hereafter, preferred embodiments according to this specification will be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings are used to indicate the same or similar components.

[0035] Although terms such as "first," "second," etc., are used to indicate various components, these components are not limited by these terms. These terms are simply used to distinguish one component from another, and unless otherwise specified, the first component may also be the second component.

[0036] Throughout the specification, unless otherwise stated, each component may be singular or plural.

[0037] In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise. Terms such as “composed of” or “including” in this application should not be interpreted as necessarily including all of the multiple components or stages described in the specification, but rather as meaning that some of the components or stages may not be included, or that further components or stages may be included.

[0038] Throughout the specification, "A and / or B" means A, B, or A and B unless otherwise specified, and "C to D" means C or greater and D or less unless otherwise specified.

[0039] In the drawings, directions can be indicated using a Cartesian coordinate system. In the specification, the first direction refers to the X-axis direction, the second direction refers to the Y-axis direction, and the third direction refers to the Z-axis direction. Also, in the specification, "upper" and "lower" refer to the upper and lower relationship in the X-axis direction.

[0040] Furthermore, when display devices are used on a daily basis, the terms "front" or "back" may be used to describe the position of an object. In this case, "front" refers to the +X direction in the drawing, and "back" refers to the -X direction in the drawing.

[0041] The display device according to the embodiments of this specification can variably provide a shared mode in which both the driver and the assistant can view the displayed image, and a personal mode in which a portion of the image in front of the assistant can be viewed only by the assistant and not by the driver.

[0042] These functional modes are referred to as Switchable Privacy Modes (SPM). Some vehicle display devices may be equipped with an SPM area to implement the SPM function.

[0043] In these SPM areas, a variable image viewable only by the assistant may be displayed. Whether the image in the SPM area is in a shared mode where both the driver and the assistant can see it, or in a personal mode where only the assistant can see it, can be selected by controlling the brightness of the light on the display unit where the image is played.

[0044] In other words, if the brightness of the display is high, it may enter shared mode, and if the brightness of the display is low, it may enter personal mode.

[0045] Thus, multiple light sources may be provided in the display device to adjust the brightness of the display. By blinking some of the multiple light sources to adjust the brightness of the light in the display, the SPM area can be variably switched between shared mode and individual mode.

[0046] Multiple light sources may be arranged sequentially below the display unit on which the image is played. Light sources located close to the display unit, i.e., above it, may be positioned to illuminate the display device laterally.

[0047] In such cases, a light guide plate may be placed to change the path of the light. On the other hand, the light guide plate can also serve to change the multiple point light sources provided in the light source unit into a face light source and emit it.

[0048] As light travels through the light guide plate, a phenomenon can occur where the point light source gradually changes into a surface light source. Consequently, the area of ​​light incident on the light guide plate may exhibit uneven light intensity, resulting in a repetitive pattern of light and dark areas. These phenomena are known as the searchlight phenomenon.

[0049] When the searchlight phenomenon occurs in the light guide plate, the uniformity of light decreases, which can degrade the image quality of the image reproduced on the display. Improvement is needed to address this. The embodiments of this specification will be described in detail below.

[0050] Figure 1 is a schematic cross-sectional view of a display device according to one embodiment. The display device according to one embodiment may include a display unit 100, a light guide plate 200, a first light source unit 300, and a second light source unit 400.

[0051] The display unit 100 can display video and images. In the following, the objects displayed on the display unit 100 can be a mix of video, images, and other visuals. A user is positioned in front of the display unit 100, and the user can obtain information necessary for driving and other desired information from the images displayed on the display unit 100.

[0052] The display unit 100 may include a display panel 110, a cover member 120, and an optical sheet 130.

[0053] The display panel 110 has multiple pixels arranged horizontally and vertically, and can reproduce an image by changing the color of each pixel. The cover member 120 is positioned above the display panel 110 and can protect the display panel 110.

[0054] The optical sheet 130 is positioned below the display panel 110, allowing light that has passed through the light guide plate 200 to enter it. The optical sheet 130 diffuses the incident light, further uniformizing the brightness of the light across the entire optical sheet 130 before emission.

[0055] The optical sheet 130 may be configured in a form in which multiple sheets having different functions are laminated together.

[0056] For example, the optical sheet 130 may include a diffusion sheet, a prism sheet, and a protective sheet. The diffusion sheet diffuses light. Light that passes through the diffusion sheet is diffused and can become even more uniform.

[0057] The prism sheet is placed above the diffusion sheet and can improve the straight-line propagation of light. Because the prism sheet has a prism structure, it can partially focus the light that enters after passing through the diffusion sheet, thereby improving the straight-line propagation of light.

[0058] The protective sheet may be placed outside the diffusion sheet or prism sheet. The protective sheet can protect the diffusion sheet and prism sheet from damage caused by external foreign objects or scratches.

[0059] The display unit 100 may include a shared area 101 and a variable personal area 102. The shared area 101 allows all users in front of the display unit 100 to view the displayed image. In a display device installed in a vehicle, the shared area 101 may be positioned close to the driver.

[0060] The variable personal area 102 can selectively display images to all users or only some users. The variable personal area 102 may be positioned close to an assistant sitting next to the driver. The area of ​​the shared area 101 may be larger than the area of ​​the variable personal area 102.

[0061] The display device of the embodiment includes a plurality of light sources, namely a first light source 300 and a second light source 400, which are arranged to be spaced apart from each other and can be turned on / off by independent control.

[0062] When the first light source unit 300 is in a heated state and emits light, the variable personal area 102 may be configured so that all users can see the displayed image, and when the first light source unit 300 is in an off state, the variable personal area 102 may be configured so that only some users can see the displayed image.

[0063] The second light source 400 may remain lit while the display device is operating. Alternatively, by blinking the first light source 300 to adjust the brightness of the light in the display unit 100, the display unit 100 can operate in a shared mode where both the driver and the assistant can view the image, or in a personal mode where the image displayed in the variable personal area 102 can only be viewed by the assistant.

[0064] This utilizes the fact that if the brightness of the display unit 100 is moderately low, a driver who views the variable personal area 102 at an angle will not be able to see the image displayed in the variable personal area 102.

[0065] To implement these SPM (Switchable Privacy Mode) functions, multiple light sources are required, some of which need to blink while the display device is operating. In this embodiment, the first light source unit 300 blinks to implement either shared mode or private mode.

[0066] The light guide plate 200 may be positioned below the display unit 100. The light guide plate 200 can convert an incident point light source into a face light source and emit light from it.

[0067] Light emitted from the first light source unit 300 enters the light guide plate 200, where it undergoes repeated total internal reflection, diffuse reflection, refraction, and diffraction to be converted into a surface light source with uniform brightness, which can then be emitted toward the display unit 100.

[0068] Light emitted from the first light source unit 300 enters the side surface of the light guide plate 200, altering the path of the light so that it can be emitted towards the display unit 100 located above the light guide plate 200.

[0069] The first light source unit 300 is positioned on one side of the light guide plate 200 and can irradiate light toward the light guide plate 200. The light source unit in this specification may consist of an LED that serves as a light source and a circuit board on which the LED is mounted. The first light source unit 300 is arranged along one side edge of the light guide plate 200 such that a plurality of LEDs are spaced apart from each other, and these LEDs may be mounted on the circuit board.

[0070] As mentioned above, in shared mode, the first light source 300 is turned on, and the brightness of the light from the display unit 100 becomes relatively high, while in personal mode, the first light source 300 is turned off, and the brightness of the light from the display unit 100 may become relatively low.

[0071] The second light source unit 400 is positioned below the light guide plate 200 and can irradiate light toward the light guide plate 200. The point light source emitted from the second light source unit 400 passes through the optical member 600 and the light control film 500, which will be described later, enters the light guide plate 200, and then exits the light guide plate 200 to enter the display unit 100.

[0072] The second light source unit 400 may include a plurality of LEDs arranged at intervals from each other in the X-axis and Y-axis directions on an XY plane perpendicular to the Z-axis direction in Figure 1, and a circuit board on which the LEDs are mounted.

[0073] One embodiment of the display device may include a light control film 500, an optical element 600, and a reflector 700.

[0074] The light control film 500 may be placed below the light guide plate 200. By irradiating the light control film 500 from the second light source unit 400 and adjusting the transmittance of the light that has passed through the optical element 600, the contrast between light and dark in the displayed image can be increased, thereby improving the clarity of the image.

[0075] Light can be incident on the portion of the light-control film 500 adjacent to the first light source 300 from the first light source 300. To allow the light incident on the light-control film 500 from the first light source 300 to travel upward, i.e., in the +Z direction, a plurality of light-reflecting diaphragms 510 may be arranged in the portion of the light-control film 500 adjacent to the first light source 300 so as to be separated from each other in a first direction.

[0076] These diaphragms 510 can improve the brightness of the display unit 100 and enhance the light efficiency of the display device.

[0077] The optical component 600 may be placed between the light control film 500 and the second light source unit 400. The optical component 600 may have a structure in which parts having different functions are laminated together. For example, the optical component 600 may include a diffusion layer and a prism layer.

[0078] The diffusion layer can diffuse the point light source incident on the second light source unit 400, converting it into a surface light with uniform brightness. The prism layer, equipped with a prism structure, can partially focus the incident light, improving the straightness of the light's propagation.

[0079] The reflector 700 may be positioned below the second light source unit 400. The reflector 700 can reflect light emitted downward from the second light source unit 400 and change the path of the light so that it travels upward towards the display unit 100.

[0080] Therefore, by directing almost all of the light emitted from the second light source unit 400 towards the display unit 100, the light efficiency of the display device can be increased.

[0081] Figure 2 is a diagram illustrating the searchlight 40 phenomenon that occurs in the light guide plate 200. Figure 2 shows the screen of the display unit 100 with no video playback, the first light source unit 300 turned on, and the display unit 100 screen being viewed. Figure 2 shows a display device equipped with a light guide plate 200 in which the emission surface pattern 210, which will be described later, is not formed.

[0082] When light from the first light source 300 enters the light guide plate 200, a phenomenon may occur in which the point light source gradually changes to a surface light source as the light travels along the light guide plate 200. Consequently, the area of ​​the light guide plate 200 into which the light enters may have uneven light intensity, and a phenomenon may occur in which bright and dark areas are repeatedly arranged. These phenomena are referred to as the searchlight phenomenon.

[0083] In the display device, the screen of the display unit 100 when these searchlight 40 phenomena occur is shown in Figure 2.

[0084] Referring to Figure 2, in the area where light enters the display unit 100, the light does not diffuse sufficiently into the light guide plate 200, so the light emitted from each LED maintains the form of a point source.

[0085] This shows that on the screen of the display unit 100, the light repeatedly changes in a second direction at the light incidence site, that is, it becomes darker in the second direction and then brighter, and the light maintains the shape of the light ray.

[0086] These searchlight 40 phenomena disappear as the light continues to travel along the light guide plate 200. This is because, as the light continues to travel, it diffuses more effectively in the second direction, resulting in a more uniform light intensity.

[0087] In other words, these searchlight 40 phenomena are more pronounced in the portion of the light guide plate 200 adjacent to the first light source, and become weaker as the distance from the first light source increases. Considering these characteristics of the searchlight 40 phenomenon, a structure that effectively suppresses the searchlight 40 and improves the light efficiency of the light guide plate 200 will be specifically described below.

[0088] In this specification, "light efficiency" may mean the efficiency of suppressing light brightness unevenness, such as the searchlight 40 phenomenon, without reducing the light brightness.

[0089] Figure 3 is a perspective view of a light guide plate 200 according to one embodiment. Figure 4 is a view of Figure 3 from another direction. The light guide plate 200 may include an emission surface pattern 210 in order to suppress the searchlight 40 phenomenon described above and to improve the uniformity of the emitted light.

[0090] The emission surface pattern 210 is formed to protrude from the upper surface of the light guide plate 200 from which light is emitted, the longitudinal direction of the emission surface pattern 210 is the first direction, and the emission surface patterns 210 may be arranged to be spaced apart from each other in a second direction that intersects the first direction.

[0091] The emission surface pattern 210 may protrude convexly from the surface of the light guide plate 200 from which light is emitted, i.e., the upper surface. As light is emitted from the light guide plate 200, it undergoes scattering, refraction, diffraction, surface total internal reflection, etc., by the emission surface pattern 210, and can have a uniform brightness on the XY plane.

[0092] In particular, the emission surface pattern 210 can diffuse light in a second direction, thereby suppressing the aforementioned searchlight 40 phenomenon. To effectively suppress the searchlight 40 phenomenon, the light needs to diffuse significantly in the second direction.

[0093] The emission surface pattern 210 in the embodiment may be arranged in a first direction whose longitudinal direction is parallel to the direction of propagation of light emitted from the first light source unit 300. Therefore, the upper surface of the light guide plate 200 has little to no change in irregularities in the first direction.

[0094] On the other hand, the emission surface pattern 210 may be provided in multiple locations and arranged to be spaced apart from each other in the second direction. Therefore, the upper surface of the light guide plate 200 has large and deep changes in its unevenness in the second direction.

[0095] The multiple LEDs in the first light source unit 300 are arranged to be spaced apart from each other in the second direction, and each LED can form a point light source. For these reasons, the searchlight 40 phenomenon exhibits a pattern of repeated high and low brightness in the second direction.

[0096] In this embodiment, as described above, the upper surface of the light guide plate 200 is formed such that the changes in unevenness are large and deep in the second direction. As a result, the light emitted from the upper surface of the light guide plate 200 undergoes significant scattering, refraction, diffraction, and total internal reflection in the second direction, which significantly suppresses the searchlight 40 phenomenon and makes the brightness of the light emitted from the light guide plate 200 uniform.

[0097] Figure 5 is a plan view of the light guide plate 200 according to one embodiment. Figure 6 is a front view of the light guide plate 200 according to one embodiment.

[0098] As shown in Figure 2, the searchlight 40 phenomenon can decrease as the light propagates. This is because the light becomes more diffuse and gradually more uniform as it propagates. The emission surface pattern 210 needs to be formed taking these light propagation characteristics into consideration.

[0099] The emission surface pattern 210 allows for greater uniformity of brightness as the depth of the irregularities on the upper surface of the light guide plate 200 increases, resulting in more pronounced scattering, refraction, diffraction, and total internal reflection.

[0100] However, while these emission surface patterns 210 can suppress the searchlight 40 phenomenon and improve brightness uniformity, they may also weaken the directivity of light, thereby reducing the overall brightness of the emitted light.

[0101] Considering this, the emission surface pattern 210 needs to have deeper irregularities in areas where the searchlight 40 phenomenon is pronounced, and shallower irregularities in areas where the searchlight 40 phenomenon is weak, in order to increase the brightness of the light and improve light efficiency.

[0102] Therefore, the emission surface pattern 210 may be configured so that its width increases as it approaches the first light source unit 300.

[0103] With this structure, the searchlight 40 phenomenon can be effectively eliminated by forming deep irregularities in a second direction by the emission surface pattern 210 in the portion adjacent to the first light source 300 where the searchlight 40 phenomenon is prominent on the upper surface of the light guide plate 200.

[0104] On the other hand, in areas of the upper surface of the light guide plate 200 that are far from the first light source 300 where the searchlight 40 phenomenon is weak, shallow irregularities can be formed in a second direction by the emission surface pattern 210 to increase the brightness of the light emitted from the light guide plate 200. The structure of the light guide plate 200 will be described in more detail below.

[0105] The light guide plate 200 may include a first region 201 and a second region 202. The first region 201 may have an emission surface pattern 210 formed thereon, and the second region 202 may be located on one side of the first region 201 and may also have an emission surface pattern 210 formed thereon. The width of the emission surface pattern 210 in the first region 201 may be smaller than the width of the emission surface pattern 210 in the second region 202.

[0106] In other words, in the first region 201, the width of the emission surface pattern 210 is relatively small. The first region 201 is a region in the light guide plate 200 that is relatively far from the incident surface of light irradiated from the first light source unit 300. The second region 202 is a region where the width of the emission surface pattern 210 is relatively large and is relatively close to the incident surface of light.

[0107] The width of the emission surface pattern 210 in the second region 202 may increase continuously (gradually) as it approaches the first light source unit 300. That is, the width of the emission surface pattern 210 may increase continuously (gradually) as it approaches the light incident surface in the light guide plate 200.

[0108] With this structure, in the first region 201 where the searchlight 40 phenomenon in the light guide plate 200 is weak, the irregularities caused by the emission surface pattern 210 are formed to be shallow, and the brightness of the light emitted from the light guide plate 200 can be increased.

[0109] Furthermore, in the second region 202 of the light guide plate 200 where the searchlight 40 phenomenon is pronounced, the widths of the emission surface patterns 210 are configured to differ from each other in the first direction. When the searchlight 40 phenomenon is pronounced, the irregularities of the emission surface patterns 210 are made deeper, and when the searchlight 40 phenomenon gradually decreases, the irregularities of the emission surface patterns 210 are made shallower, thereby increasing the light efficiency.

[0110] As mentioned above, the searchlight 40 phenomenon is relatively weak in the shared area 101 of the display unit 100, while it is relatively pronounced in the variable personal area 102. Therefore, the first area 201 is located in a position corresponding to the shared area 101, and the second area 202 is located in a position corresponding to the variable personal area 102.

[0111] With this structure, the common area 101 of the display unit 100 may overlap with the first area 201 in at least a portion, and the variable personal area 102 of the display unit 100 may overlap with the second area 202 in at least a portion.

[0112] Of course, the shared area and the first area 201 are not positioned to perfectly coincide with each other, nor are the variable personal area 102 and the second area 202 positioned to perfectly coincide with each other.

[0113] Figure 7 shows a portion of the bottom surface of the light guide plate 200 according to one embodiment. Figure 8 is an enlarged view of a portion of Figure 6. The arrows in Figure 8 indicate that the path of light emitted to the bottom surface of the light guide plate 200 is altered by the bottom surface pattern 220.

[0114] The light guide plate 200 may include a bottom surface pattern 220 that is positioned to protrude toward the second light source unit 400 on its lower surface. Multiple bottom surface patterns 220 may be provided, and as shown in Figure 4, each bottom surface pattern 220 may be arranged on the XY plane at regular intervals in the first and second directions.

[0115] The lower surface pattern 220 can improve the light efficiency of the display device by reflecting the light emitted from the first light source unit 300 when it is emitted from the lower surface of the light guide plate 200, thereby changing the path of the light and causing it to enter the light guide plate 200 again.

[0116] In this case, the lower surface pattern 220 is a transparent structure through which light passes, but the path of the light can be changed by totally reflecting the light emitted from the lower surface pattern 220.

[0117] The lower surface pattern 220 may be formed in a pyramidal shape, and the area of ​​the first surface 221 facing the first light source unit 300 may be larger than the area of ​​the second surface 222 facing in the opposite direction from the first light source unit 300.

[0118] With this structure, as shown in Figure 8, the first inclination of the second surface 222, which faces in the opposite direction to the first light source 300, may be steeper than the first inclination of the first surface 221, which faces the first light source 300, in the first direction.

[0119] Therefore, the light emitted from the lower surface of the light guide plate 200 undergoes total internal reflection at the first surface 221, which is formed by a relatively steep inclined surface. This abruptly changes the path of the light, allowing it to re-enter the light guide plate 200.

[0120] Figure 9 is a right side view of Figure 6. As shown in Figure 9, the emission surface pattern 210 may be formed such that the cross section cut in the second direction is a semicircular or semielliptical shape that protrudes convexly from the upper surface of the light guide plate 200.

[0121] The protruding height of the ejection surface pattern 210 can be proportional to the width of the ejection surface pattern 210. That is, the wider the ejection surface pattern 210, the greater the height of the ejection surface pattern 210 can be.

[0122] The light guide plate 200 may include a side pattern 230 arranged on its side so as to protrude toward the first light source unit 300. The side pattern 230 may be formed on the light incident surface of the light guide plate 200 that faces the first light source unit 300.

[0123] Light emitted from the first light source 300 passes through the side pattern 230, undergoing scattering, refraction, diffraction, etc., and diffusing, which can improve the uniformity of the light incident on the light guide plate 200. The side pattern 230, together with the exit surface pattern 210, can reduce the searchlight 40 phenomenon.

[0124] The wider the side pattern 230, the better the uniformity of the light, but the less bright the light may be. Therefore, the width of the side pattern 230 can be appropriately selected, taking into consideration this point and the area of ​​the incident surface of the light guide plate 200.

[0125] The longitudinal direction of the side pattern 230 may be a second direction. The side pattern 230 may include a plurality of side patterns. These plurality of side patterns may be arranged to be spaced apart from each other in a third direction that intersects the first and second directions.

[0126] The LEDs of the first light source unit 300 may include a plurality of LEDs. These plurality of LEDs may be arranged so as to be spaced apart from each other at regular intervals in a second direction. Therefore, the longitudinal direction of the first light source unit 300 may be the second direction. Correspondingly, the longitudinal direction of each of the plurality of side patterns 230 may be the second direction. The plurality of side patterns 230 may be arranged so as to be spaced apart from each other in a third direction.

[0127] The cross-sectional shape obtained by cutting the side pattern 230 in a third direction may be a semicircular or semi-elliptical shape that protrudes convexly from the side surface of the light guide plate 200.

[0128] The side pattern 230 may be configured to have a constant width in the second direction. The incident surface of the light guide plate 200 on which the side pattern 230 is formed can be incident on a uniform point light source in the second direction. Accordingly, the side pattern 230 may be configured to have a constant width in the second direction in order to uniformly diffuse the light in the second direction.

[0129] The exit surface pattern 210 may be formed by injection molding using a mold 20. To form the exit surface pattern 210, the mold 20 may have a shape that corresponds to the shape of the exit surface pattern 210.

[0130] However, since the ejection surface pattern 210 is formed with different widths in the first direction, it may be somewhat difficult to form these shapes in the mold 20. Below, we will specifically describe a method for easily forming shapes corresponding to the ejection surface pattern 210 in the mold 20.

[0131] Figure 10 is a schematic diagram showing the mold 20 and the pressurizing tool 30. The mold 20 shown in Figure 10 and subsequent figures is the part of the mold 20 used to produce the shape of the upper surface of the light guide plate 200 and the ejection surface pattern 210 of the light guide plate 200, out of the overall mold 20 used to inject the light guide plate 200.

[0132] The mold 20 can be pressurized with a pressurizing tool 30 to form a shape corresponding to the injection surface pattern 210. When the mold 20 is pressurized by the pressurizing tool 30, forming grooves 31 that form the injection surface pattern 210 are formed in the mold 20, and the forming grooves 31 may have a shape corresponding to the injection surface pattern 210.

[0133] The pressurizing tool 30 may be configured to advance continuously in a first direction relative to the mold 20 to create a forming groove 31, and the depth of contact with the mold 20 may change as it advances in the first direction.

[0134] By continuously moving the pressurizing tool 30 relative to the mold 20 in a first direction, and changing the contact depth between the pressurizing tool 30 and the mold 20 according to each region, forming grooves 31 of different depths are created in the first direction. Furthermore, this method allows the creation of one forming groove 31 to be completed in a single movement.

[0135] Therefore, since it is not necessary to separate and cut each part of the mold 20 with a separate cutting tool in order to produce forming grooves 31 of different depths in the first direction, the mold 20 can be easily manufactured, the manufacturing time of the light guide plate 200 can be shortened, and manufacturing costs can be effectively saved.

[0136] Figure 11 is a front view of a light guide plate 200 according to one embodiment. Figure 12 is a cross-sectional view of the mold 20 at point A, which corresponds to the point shown on the light guide plate 200 in Figure 11. Figure 13 is a cross-sectional view of the mold 20 at point B, which corresponds to the point shown on the light guide plate 200 in Figure 11. Figure 14 is a cross-sectional view of the mold 20 at point C, which corresponds to the point shown on the light guide plate 200 in Figure 11.

[0137] In the embodiment, the distance (D) between adjacent ejection surface patterns 210 in the second direction and the corresponding forming grooves 31 may be, for example, about 50 μm. However, the distance (D) is not limited thereto.

[0138] If the cross-section of the ejection surface pattern is semicircular, the width of the ejection surface pattern 210 may be twice the height of the ejection surface pattern 210 and the depth of the forming groove 31. If the cross-section of the ejection surface pattern is semielliptical, the width of the ejection surface pattern 210 may be greater than twice the height of the ejection surface pattern 210 and the depth of the forming groove 31. The following explanation will use the case where the cross-section of the ejection surface pattern is semicircular as an example.

[0139] When forming grooves 31 in the mold 20, the pressurizing tool 30 can contact the mold 20 at a relatively small depth in a position corresponding to the first region 201 of the mold 20, and at a relatively large depth in a position corresponding to the second region 202 of the mold 20.

[0140] The pressurizing tool 30 may be configured such that, as it moves toward the direction corresponding to the first light source unit 300 at a position corresponding to the second region 202, the contact depth with the mold 20 increases continuously (gradually).

[0141] In Figures 12 to 14, point A belongs to the part of the mold 20 corresponding to the first region 201 of the light guide plate 200, and points B and C belong to the parts of the mold 20 corresponding to the second region 202 of the light guide plate 200. In particular, point C is one end of the exit surface pattern 210 on the light guide plate 200 where the width of the exit surface pattern 210 is maximum.

[0142] The depth of the formed grooves 31 at point A is minimal, and the depth of these formed grooves 31 can be kept constant in the area corresponding to the first region 201. The depth (H1) of the formed grooves 31 at point A may be, for example, 0.1 μm. However, the depth (H1) is not limited to this.

[0143] The depth (H3) of the groove 31 at point C may be 10 μm, but is not limited to this. The depth (H2) of the groove 31 at point B may be, for example, greater than 0.1 μm and less than 10 μm, but is not limited to this.

[0144] The depth of the formed groove 31 at point B may increase continuously (gradually) as it progresses in the direction corresponding to the first light source unit 300.

[0145] With the structure described above, a mold 20 having a forming groove 31 can be manufactured, and the light guide plate 200 according to the embodiment can be easily manufactured by injection molding using these molds 20.

[0146] A display device according to one embodiment includes a display unit, a light guide plate disposed below the display unit, a first light source unit disposed on one side of the light guide plate and irradiating light toward the light guide plate, and a second light source unit disposed below the light guide plate and irradiating light toward the light guide plate, wherein the light guide plate includes a plurality of emission surface patterns, the plurality of emission surface patterns are formed to protrude from the upper surface from which light is emitted, the longitudinal direction of each of the plurality of emission surface patterns is a first direction, the plurality of emission surface patterns are arranged to be separated from each other in a second direction intersecting the first direction, and the width of each of the plurality of emission surface patterns may be configured to increase as the plurality of emission surface patterns move toward the first light source unit.

[0147] The shape of the cross-section obtained by cutting the emission surface pattern in the second direction may be a semicircular or semielliptical shape that protrudes convexly from the upper surface of the light guide plate.

[0148] The light guide plate includes a first region on which the emission surface pattern is formed, and a second region disposed on one side of the first region on which the emission surface pattern is formed, wherein the width of the emission surface pattern in the first region is smaller than the width of the emission surface pattern in the second region, and the width of the emission surface pattern in the second region may be configured to increase continuously as it approaches the first light source.

[0149] The ejection surface pattern is formed by injection molding using a mold, and the mold may be pressurized by a pressurizing tool so that forming grooves for forming each of the plurality of ejection surface patterns are defined in the mold.

[0150] The pressurizing tool may be configured to advance continuously in the first direction relative to the mold to create the forming groove, and for the depth of contact with the mold to change as it advances in the first direction.

[0151] The pressurizing tool can contact the mold at a position corresponding to the first region of the mold, at a depth smaller than that at a position corresponding to the second region.

[0152] The pressurizing tool may be configured such that, at a position corresponding to the second region, the contact depth with the mold continuously increases as it moves toward the direction corresponding to the first light source.

[0153] The light guide plate may include a bottom surface pattern positioned on its lower surface so as to protrude toward the second light source unit, and a side surface pattern positioned on its side so as to protrude toward the first light source unit.

[0154] The lower surface pattern is formed in a pyramidal shape, and the area of ​​the first surface facing the first light source may be larger than the area of ​​the second surface facing the opposite direction from the first light source.

[0155] The longitudinal direction of the side pattern is the second direction, and the side pattern includes a plurality of side patterns, which may be arranged to be spaced apart from each other in a third direction that intersects the first and second directions.

[0156] The cross-sectional shape obtained by cutting the side pattern in the third direction is a semicircular or semi-elliptical shape that protrudes convexly from the side of the light guide plate, and the side pattern may have a constant width along the second direction.

[0157] The display unit includes a shared area where the displayed image can be viewed by all users in front of the display unit, and a variable personal area where the displayed image can be selectively viewed by all or some users, wherein the shared area may overlap with the first area in at least a portion, and the variable personal area may overlap with the second area in at least a portion.

[0158] When the first light source is turned on, the image displayed on the variable personal area may be visible to all users, and when the first light source is turned off, the image displayed on the variable personal area may be visible to only some users.

[0159] The display unit may include a display panel on which an image is reproduced, a cover member positioned above the display panel, and an optical sheet positioned below the display panel, into which light that has passed through the light guide plate is incident.

[0160] The display device may include a light control film disposed below the light guide plate, an optical member disposed between the light control film and the second light source unit, and a reflector disposed below the second light source unit.

[0161] As described above, this specification has been explained with reference to the illustrative drawings, but it is clear that this specification is not limited to the embodiments and drawings disclosed herein, and that various modifications can be made by a person of the ordinary skill within the scope of the technical concept of this specification. Furthermore, even if the effects of the configuration described herein are not explicitly stated and explained in the embodiments described above, it is natural that the effects that can be predicted by such configuration should also be recognized.

Claims

1. The display unit, A light guide plate is positioned below the display unit, A first light source unit is positioned on one side of the light guide plate and irradiates light toward the light guide plate, A second light source unit is positioned below the light guide plate and irradiates light toward the light guide plate, Includes, The light guide plate includes a plurality of emission surface patterns, The plurality of emission surface patterns are formed to protrude from the upper surface from which light is emitted. The longitudinal direction of each of the aforementioned plurality of ejection surface patterns is the first direction. The plurality of ejection surface patterns are arranged to be separated from each other in a second direction that intersects with the first direction. The width of each of the plurality of emission surface patterns increases as the plurality of emission surface patterns move toward the first light source. Display device.

2. The display device according to claim 1, wherein the shape of the cross section obtained by cutting the emission surface pattern in the second direction is a semicircular or semielliptical shape that protrudes convexly from the upper surface of the light guide plate.

3. The light guide plate is The first region where the aforementioned injection surface pattern is formed, A second region is located on one side of the first region, and the emission surface pattern is formed therein. Includes, The width of the exit surface pattern in the first region is smaller than the width of the exit surface pattern in the second region. The emission surface pattern in the second region is configured such that its width continuously increases as it approaches the first light source. The display device according to claim 1.

4. The aforementioned injection surface pattern is formed by injection molding using a mold. The mold is pressurized by a pressurizing tool so that forming grooves for forming each of the plurality of injection surface patterns are defined in the mold. The display device according to claim 3.

5. The display device according to claim 4, wherein the pressurizing tool is configured to advance continuously in a first direction relative to the mold to create the forming groove, and the depth of contact with the mold changes as it advances in the first direction.

6. The display device according to claim 5, wherein the pressurizing tool contacts the mold at a position corresponding to the first region of the mold, to a depth smaller than that at a position corresponding to the second region.

7. The display device according to claim 6, wherein the pressurizing tool is configured such that the contact depth with the mold continuously increases as it moves toward the direction corresponding to the first light source at a position corresponding to the second region.

8. The light guide plate is A lower surface pattern is positioned on the lower surface so as to protrude toward the second light source section, A side pattern is arranged on the side so as to protrude toward the first light source section, The display device according to claim 1, including the following:

9. The aforementioned lower surface pattern is formed in a pyramidal shape, The area of ​​the first surface facing the first light source is greater than the area of ​​the second surface facing the opposite direction from the first light source. The display device according to claim 8.

10. The longitudinal direction of the side pattern is the second direction, The aforementioned side pattern includes a plurality of side patterns, The plurality of side patterns are arranged so as to be separated from each other in a third direction that intersects the first and second directions. The display device according to claim 8.

11. The shape of the cross-section obtained by cutting the side pattern in the third direction is a semicircular or semielliptical shape that protrudes convexly from the side surface of the light guide plate. The side pattern has a constant width along the second direction, The display device according to claim 10.

12. The aforementioned display unit is The displayed image is viewed by all users in front of the display unit in a shared area, A variable personal area that allows all or some users to selectively view the displayed image, Includes, The shared area overlaps with the first area in at least a portion of it. The variable personal region overlaps with the second region in at least a portion thereof. The display device according to claim 3.

13. When the first light source is turned on, the image displayed on the variable personal area can be seen by all users. When the first light source is turned off, the image displayed on the variable personal area can only be seen by some users. It is structured in such a way. The display device according to claim 12.

14. The aforementioned display unit is A display panel on which images are played, A cover member positioned above the display panel, An optical sheet is positioned below the display panel, into which light that has passed through the light guide plate is incident; The display device according to claim 1, including the following:

15. A light control film is positioned below the light guide plate, An optical member disposed between the light control film and the second light source unit, A reflector positioned below the second light source unit, The display device according to claim 1, including the following:

Images