KR102560742B1 - Liquid Crystal Display device having two prism sheet - Google Patents

Abstract

A liquid crystal display device is provided. The liquid crystal display device may include a liquid crystal panel, a backlight unit, a mold frame, and a light blocking tape. The backlight unit may include two prism sheets. The mold frame may include an inner space in which the two prism sheets are accommodated. The light blocking tape may be positioned between the mold frame and the liquid crystal panel. The light blocking tape may extend between the two prism sheets.

Description

Liquid crystal display device having two prism sheets {Liquid Crystal Display device having two prism sheets}

The present invention relates to a liquid crystal display device in which a backlight unit includes two prism sheets.

In general, electronic devices such as monitors, TVs, laptops, digital cameras, and the like include image implementation devices. The image implementation device may include a flat panel display device such as a liquid crystal display device and an organic light emitting display device.

The liquid crystal display device may implement an image by adjusting the transmittance of the liquid crystal. For example, the liquid crystal display may include a liquid crystal panel containing liquid crystal, a backlight unit supplying light to the liquid crystal panel, a mold frame partially accommodating the backlight unit, and a light blocking tape disposed between the mold frame and the liquid crystal panel.

The backlight unit may include a light guide plate including a light incident surface, at least one light source positioned on the light incident surface of the light guide plate, and an optical sheet for improving characteristics of light supplied from the light guide plate to the liquid crystal panel. For example, the optical sheet may include a diffusion sheet and two prism sheets.

The light blocking tape may extend onto the optical sheet. Among the optical sheets, an upper prism sheet positioned relatively close to the liquid crystal panel may be adhered to the light blocking tape. Since the side surface of the diffusion sheet facing the light source is positioned outside the upper prism sheet, the diffusion sheet may be partially adhered to the light blocking tape.

However, since the lower prism sheet positioned between the diffusion sheet and the upper prism sheet does not adhere to the light blocking tape, it may move due to an external impact or the like. Flow of the lower prism sheet may deteriorate characteristics of light supplied to the liquid crystal panel.

In addition, when the side surface of the lower prism sheet toward the light source is extended and adhered to the light blocking tape, light generated by the light source is supplied to the liquid crystal panel without passing through the upper prism sheet, causing light leakage.

In addition, if the side surfaces of the lower prism sheet, except for the side facing the light source, are extended and adhered to the light blocking tape, a problem may arise in that the overall area is increased in order to secure a sufficient bonding space.

An object of the present invention is to provide a liquid crystal display device capable of preventing movement of a lower prism sheet and an upper prism sheet due to external impact without light leakage and an increase in overall area.

Another problem to be solved by the present invention is to provide a liquid crystal display capable of improving the uniformity of light supplied to the liquid crystal panel.

The problems to be solved by the present invention are not limited to the aforementioned problems. Subjects not mentioned herein will be clearly understood by those skilled in the art from the following description.

A liquid crystal display device according to the technical idea of the present invention for achieving the above object is a backlight unit including a lower prism sheet and an upper prism sheet positioned on the lower prism sheet; a mold frame including an inner space in which the lower prism sheet and the upper prism sheet are accommodated; a liquid crystal panel positioned on the backlight unit and the mold frame; and a light blocking tape positioned between the mold frame and the liquid crystal panel. The light blocking tape extends between the lower prism sheet and the upper prism sheet.

The light blocking tape may be directly adhered to edges of the lower prism sheet and edges of the upper prism sheet.

The liquid crystal display device may further include a lower air gap positioned between the lower prism sheet, the upper prism sheet, and the light blocking tape.

A surface of the upper prism sheet exposed by the lower air gap may be parallel to a surface of the lower prism sheet facing the upper prism sheet.

The liquid crystal display device may further include an upper air gap positioned between the backlight unit, the liquid crystal panel, and the light blocking tape.

A side surface of the upper prism sheet may be exposed by the upper air gap.

The backlight unit may further include a light guide plate including a light incident surface, at least one light source positioned on the light incident surface of the light guide plate, a diffusion sheet positioned on a surface of the light guide plate facing the liquid crystal panel, and a reflector positioned on a surface of the light guide plate facing the liquid crystal panel. The lower prism sheet may be positioned between the upper prism sheet and the diffusion sheet.

A side surface of the lower prism sheet facing the light source may be vertically aligned with the upper prism sheet.

An area of the upper prism sheet may be smaller than that of the lower prism sheet.

In the liquid crystal display device according to the technical idea of the present invention, the lower prism sheet and the upper prism sheet may be fixed using a light blocking tape without light leakage and an increase in overall area. In addition, in the liquid crystal display device according to the technical concept of the present invention, the uniformity of light supplied to the liquid crystal panel can be improved. Accordingly, in the liquid crystal display device according to the technical idea of the present invention, the quality of an image implemented can be improved.

1 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.
FIG. 2 is a view showing a cross section taken along the line II' of FIG. 1 .
FIG. 3 is an enlarged view of region P of FIG. 2 .
4 is a cross-sectional view of a liquid crystal display according to another embodiment of the present invention.
FIG. 5 is a view showing a positional relationship between a lower prism sheet and an upper prism sheet of FIG. 4 .

The above objects and technical configurations of the present invention and details of the operation and effect thereof will be more clearly understood by the following detailed description with reference to the drawings illustrating the embodiments of the present invention. Here, since the embodiments of the present invention are provided to sufficiently convey the technical spirit of the present invention to those skilled in the art, the present invention may be embodied in other forms so as not to be limited to the embodiments described below.

Also, parts denoted by the same reference numerals throughout the specification mean the same components, and the length and thickness of a layer or region in the drawings may be exaggerated for convenience. In addition, when the first component is described as being “on” the second component, the first component is not only located on the upper side in direct contact with the second component, but also includes the case where the third component is located between the first component and the second component.

Here, terms such as first and second are used to describe various components, and are used for the purpose of distinguishing one component from another. However, the first component and the second component may be named arbitrarily according to the convenience of those skilled in the art within the scope of the technical idea of the present invention.

Terms used in the specification of the present invention are only used to describe specific embodiments, and are not intended to limit the present invention. For example, a component expressed in the singular number includes a plurality of components unless the context clearly indicates only the singular number. In addition, in the specification of the present invention, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but it should be understood that the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof is not excluded in advance.

In addition, unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and are not interpreted in an ideal or excessively formal meaning unless explicitly defined in the specification of the present invention.

(Example)

1 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention. FIG. 2 is a view showing a cross section taken along the line II' of FIG. 1 . FIG. 3 is an enlarged view of region P of FIG. 2 .

Referring to FIGS. 1 to 3 , a liquid crystal display according to an embodiment of the present invention may include a liquid crystal panel 100 , a backlight unit 200 , a mold frame 300 and a light blocking tape 400 .

The liquid crystal panel 100 may implement an image by adjusting transmittance of liquid crystal. The liquid crystal panel 100 may include a lower substrate 110 and an upper substrate 120 bonded to the lower substrate 110 . Liquid crystal may be positioned between the lower substrate 110 and the upper substrate 120 .

The lower substrate 110 may be a TFT substrate. For example, on the surface of the lower substrate 110 facing the upper substrate 120, gate lines, data lines crossing the gate lines, thin film transistors positioned at intersections of the gate lines and the data lines, and pixel electrodes individually connected to the thin film transistors may be positioned.

The upper substrate 120 may be a color filter substrate. For example, common electrodes and color filters may be positioned on the surface of the upper substrate 120 facing the lower substrate 110 .

The common electrode may form an electric field with the pixel electrodes. An electric field between the common electrode and the pixel electrodes may rotate liquid crystal located in a corresponding region. Transmittance of the rotated liquid crystal may be changed.

The color filters may allow light passing through the liquid crystal to have a specific color. For example, each color filter can transmit only light of a specific wavelength. The color filters may include red color filters, green color filters, and blue color filters. Each color filter may be positioned to face a corresponding pixel electrode.

The liquid crystal panel 100 may further include a driver IC 115. The driver IC 115 may control thin film transistors positioned on the lower substrate 110 . The driver IC 115 may be mounted on the same surface as the thin film transistors. For example, the driver IC 115 may be located on a surface of the lower substrate 110 facing the upper substrate 120 . The upper substrate 120 may expose a surface of a predetermined area of the lower substrate 110 where the driver IC 115 is located. For example, the upper substrate 120 may have a smaller area than the lower substrate 110 .

The liquid crystal panel 100 may further include a lower polarizing plate 130 and an upper polarizing plate 140 . The lower polarizing plate 130 may be positioned on the lower substrate 110 . The upper polarizing plate 140 may be positioned on the upper substrate 120 . For example, the lower substrate 110 and the upper substrate 120 may be positioned between the lower polarizing plate 130 and the upper polarizing plate 140 .

The lower polarizer 130 and the upper polarizer 140 may polarize transmitted light. The upper polarizer 140 may polarize light in a direction different from that of the lower polarizer 130 . For example, the upper polarizer 140 may polarize light in a direction perpendicular to the lower polarizer 130 .

The backlight unit 200 may supply light to the liquid crystal panel 100 . For example, the backlight unit 200 may be positioned on the lower substrate 110 of the liquid crystal panel 100 . The backlight unit 200 may include a light source assembly 210 , a light guide plate 220 , a reflector 230 and an optical sheet 240 .

The light source assembly 210 may generate light to be supplied to the liquid crystal panel 100 . For example, the light source assembly 210 may include a printed circuit board 212 including at least one light source 211 and a circuit for controlling the light source 211 . The light source 211 may be mounted on the printed circuit board 212 . For example, the light source 211 may include an LED lamp.

The light guide plate 220 may supply light generated by the light source assembly 210 to the entire liquid crystal panel 100 . For example, the light source 211 may be located on one side of the light guide plate 220 . A side surface of the light guide plate 220 facing the light source 211 may be defined as a light incident surface.

The reflection plate 230 can improve the efficiency of light supplied from the light guide plate 220 to the liquid crystal panel 100 . For example, the reflector 230 may reflect light emitted from the light guide plate 220 in a direction opposite to that of the liquid crystal panel 100 toward the liquid crystal panel 100 . The light guide plate 220 may be positioned between the liquid crystal panel 100 and the reflector 230 .

The optical sheet 240 may improve characteristics of light supplied from the light guide plate 220 to the liquid crystal panel 100 . The optical sheet 240 may be positioned between the light guide plate 220 and the liquid crystal panel 100 . For example, the optical sheet 240 may include a diffusion sheet 241 , a lower prism sheet 242 , and an upper prism sheet 243 .

The diffusion sheet 241 may improve uniformity of light passing from the light guide plate 220 to the liquid crystal panel 100 . For example, the diffusion sheet 241 may diffuse light emitted from the light guide plate 220 .

The diffusion sheet 241 may be positioned close to the light guide plate 220 . For example, the diffusion sheet 241 may directly contact the light guide plate 220 .

The lower prism sheet 242 and the upper prism sheet 243 may improve the luminance of light passing through the diffusion sheet 241 toward the liquid crystal panel 100 . For example, the lower prism sheet 242 and the upper prism sheet 243 may condense light supplied to the liquid crystal panel 100 .

The lower prism sheet 242 may be positioned between the diffusion sheet 241 and the upper prism sheet 243 . The lower prism sheet 242 may be positioned close to the diffusion sheet 241 . For example, the lower prism sheet 242 may directly contact the diffusion sheet 241 .

The lower prism sheet 242 may have a smaller area than the diffusion sheet 241 . For example, a side surface 242S of the lower prism sheet 242 facing the light source 211 may be located inside than a side surface of the diffusion sheet 241 .

The lower prism sheet 242 may have the same area as the upper prism sheet 243 . For example, side surfaces of the lower prism sheet 242 may be vertically aligned with corresponding side surfaces of the upper prism sheet 243 .

The mold frame 300 may include an inner space 300s in which a part of the backlight unit 200 is accommodated. For example, the light guide plate 220 and the optical sheet 240 may be accommodated in the inner space 300s of the mold frame 300 . Light may not be emitted toward the side of the light guide plate 220 by the mold frame 300 .

The mold frame 300 may be fixed on the reflector 230 . The reflection plate 230 may have a larger area than the light guide plate 220 . The liquid crystal display device according to an embodiment of the present invention may further include an adhesive member 500 positioned between the reflector 230 and the mold frame 300 .

The mold frame 300 may further include an accommodation groove 300g into which the light source 211 is inserted. The receiving groove 300g of the mold frame 300 may be opened only in the direction of the light incident surface LS of the light guide plate 220 . Light generated by the light source 211 may propagate only in the direction of the light incident surface LS of the light guide plate 220 by the mold frame 300 .

The light blocking tape 400 may be positioned between the liquid crystal panel 100 and the mold frame 300 . The mold frame 300 may be attached to the liquid crystal panel 100 by the light blocking tape 400 . For example, the light blocking tape 400 may be a double-sided tape.

The light blocking tape 400 may prevent light emitted from the backlight unit 200 from entering the non-display area of the liquid crystal panel 100 . The non-display area of the liquid crystal panel 100 may vertically overlap the light blocking tape 400 . For example, the light blocking tape 400 may vertically overlap an edge of the optical sheet 240 .

The light blocking tape 400 may extend between the lower prism sheet 242 and the upper prism sheet 243 . The lower prism sheet 242 and the upper prism sheet 243 may be fixed by the light blocking tape 400 . For example, the edge of the lower prism sheet 242 and the edge of the upper prism sheet 243 may be directly adhered to the light blocking tape 400 .

In the liquid crystal display according to the embodiment of the present invention, the lower prism sheet 242 and the upper prism sheet 243 may be bonded to the light blocking tape 400 . Accordingly, in the liquid crystal display device according to the exemplary embodiment of the present invention, separation of the lower prism sheet 242 and the upper prism sheet 243 due to external impact may be prevented by the light blocking tape 400 . Also, in the liquid crystal display according to the exemplary embodiment of the present invention, side surfaces of the lower prism sheet 242 may be vertically aligned with side surfaces of the upper prism sheet 243 . Therefore, in the liquid crystal display according to the exemplary embodiment of the present invention, the flow of the lower prism sheet 242 can be prevented without causing light leakage and increasing the overall area.

The liquid crystal display according to an embodiment of the present invention may be formed by changing the assembly order of the optical sheet 240 and the light blocking tape 400 . For example, the liquid crystal display according to the embodiment of the present invention may be formed by assembling the lower prism sheet 242 on the diffusion sheet 241, assembling the light blocking tape 400 on the lower prism sheet 242, and then assembling the upper prism sheet 243 on the light blocking tape 400. Therefore, in the liquid crystal display device according to the exemplary embodiment of the present invention, movement of the lower prism sheet 242 due to external impact or the like can be prevented without adding a special process.

The upper prism sheet 243 that does not overlap with the light blocking tape 400 may be spaced apart from the lower prism sheet 242 . For example, the liquid crystal display according to the embodiment of the present invention may further include a lower air gap AG1 positioned between the lower prism sheet 242 , the upper prism sheet 243 , and the light blocking tape 400 .

Light passing through the lower prism sheet 242 and proceeding to the upper prism sheet 243 may be diffused by the lower air gap AG1. That is, in the liquid crystal display device according to the embodiment of the present invention, the light traveling from the light guide plate 220 toward the liquid crystal panel 100 may be first diffused by the diffusion sheet 241 and secondarily diffused by the lower air gap AG1. Therefore, in the liquid crystal display according to the embodiment of the present invention, the uniformity of light supplied to the liquid crystal panel 100 can be improved.

A surface of the upper prism sheet 243 exposed by the lower air gap AG1 may be parallel to a surface of the lower prism sheet 242 facing the upper prism sheet 243 . That is, in the liquid crystal display according to the embodiment of the present invention, the height of the lower air gap AG1 may not change depending on the position. Accordingly, in the liquid crystal display according to the exemplary embodiment of the present invention, diffusion by the lower air gap AG1 may be uniformly generated throughout. Therefore, in the liquid crystal display device according to the embodiment of the present invention, uniformity of light supplied to the liquid crystal panel 100 can be uniformly improved as a whole.

The top of the light blocking tape 400 may be higher than the top of the optical sheet 240 . For example, the upper prism sheet 243 may be spaced apart from the lower polarizing plate 130 . The light blocking tape 400 may directly contact the lower polarizing plate 130 . The liquid crystal display according to an embodiment of the present invention may further include an upper air gap AG2 positioned between the liquid crystal panel 100 , the backlight unit 200 and the light blocking tape 400 .

Light passing through the upper prism sheet 243 and proceeding to the liquid crystal panel 100 may be diffused by the upper air gap AG2. That is, in the liquid crystal display device according to the embodiment of the present invention, the light emitted from the light guide plate 220 toward the liquid crystal panel 100 is first diffused by the diffusion sheet 241, secondarily diffused by the lower air gap AG1, thirdly diffused by the upper air gap AG2, and then supplied to the liquid crystal panel 100. Therefore, in the liquid crystal display according to the embodiment of the present invention, the uniformity of light supplied to the liquid crystal panel 100 can be greatly improved.

The upper air gap AG2 may be positioned between the liquid crystal panel 100 and the upper prism sheet 243 . An edge of the upper prism sheet 243 may be positioned between the liquid crystal panel 100 and the light blocking tape 400 . Accordingly, in the liquid crystal display according to the embodiment of the present invention, the side surface of the upper prism sheet 243 may be exposed by the upper air gap AG2.

The upper prism sheet 243 may be parallel to the lower prism sheet 242 . A surface of the upper prism sheet 243 facing the liquid crystal panel 100 exposed by the upper air gap AG2 may be parallel to a surface of the liquid crystal panel 100 facing the backlight unit 200 . Accordingly, in the liquid crystal display according to the exemplary embodiment of the present invention, diffusion by the upper air gap AG2 may be uniformly generated throughout. Therefore, in the liquid crystal display device according to the embodiment of the present invention, uniformity of light supplied to the liquid crystal panel 100 can be uniformly improved as a whole.

As a result, in the liquid crystal display device according to the embodiment of the present invention, movement of the lower prism sheet 242 due to external impact can be prevented and uniformity of light supplied to the liquid crystal panel 100 can be improved without occurrence of light leakage and an increase in the overall area by the light blocking tape 400 extending between the lower prism sheet 242 and the upper prism sheet 243.

In order to prevent light leakage in the liquid crystal display according to the exemplary embodiment, side surfaces of the lower prism sheet 242 are vertically aligned with side surfaces of the upper prism sheet 243 . However, the light leakage phenomenon due to the area difference between the lower prism sheet 242 and the upper prism sheet 243 occurs because some of the light generated by the light source 211 does not pass through the upper freeze sheet 243 and is supplied to the liquid crystal panel 100. occurrence can be prevented.

Accordingly, as shown in FIGS. 4 and 5 , in the liquid crystal display device according to another embodiment of the present invention, the side surface 242S of the lower prism sheet 242 facing the light source 211 is vertically aligned with the side surface of the upper prism sheet 243. That is, in the liquid crystal display according to another embodiment of the present invention, the area of the upper prism sheet 243 may be smaller than that of the lower prism sheet 242 .

In the liquid crystal display according to another embodiment of the present invention, the light blocking tape 400 extending between the lower prism sheet 242 and the upper prism sheet 243 may be gently bent. Accordingly, in the liquid crystal display device according to another embodiment of the present invention, the stress of the upper prism sheet 243 caused by the curved area of the light blocking tape 400 can be reduced. That is, in the liquid crystal display device according to another embodiment of the present invention, deformation of the lower prism sheet 242 and the upper prism sheet 243 due to the curved light blocking tape 400 can be prevented. Therefore, in the liquid crystal display device according to another embodiment of the present invention, the uniformity of light supplied to the liquid crystal panel 100 is improved, and the lower prism sheet 242 and the upper prism sheet 243 can be securely fixed by the light blocking tape 400.

100: liquid crystal panel 200: backlight unit
210: light source assembly 220: light guide plate
230: reflector 240: optical sheet
241: diffusion sheet 242: lower prism sheet
243: upper prism sheet 300: mold frame
400: light blocking tape AG1: lower air gap
AG2: upper air gap

Claims (10)

a backlight unit including a lower prism sheet positioned on the light guide plate and an upper prism sheet positioned on the lower prism sheet;
a mold frame providing an internal space in which the light guide plate, the lower prism sheet, and the upper prism sheet are accommodated, and including a body portion surrounding a side surface of the light guide plate and a side wall portion protruding from a first region of the body portion positioned on three surfaces of the light guide plate except for a light incident surface;
a liquid crystal panel disposed on the backlight unit and the mold frame, including a lower polarizing plate disposed on a lower substrate and an upper polarizing plate disposed on an upper substrate bonded to the lower substrate; and
A light-shielding tape positioned between the mold frame and the liquid crystal panel and including a region positioned on the sidewall portion of the mold frame,
The light-shielding tape extends between the lower prism sheet and the upper prism sheet, and a lower air gap is positioned between the light-shielding tape, the lower prism sheet, and the upper prism sheet;
The lower polarizing plate of the liquid crystal panel is in contact with the light blocking tape on the sidewall of the mold frame, so that an upper air gap is positioned between the light blocking tape, the upper prism sheet, and the lower polarizing plate;
An edge of the lower prism sheet and an edge of the upper prism sheet contact an end of the light blocking tape on the body. delete delete According to claim 1,
A surface of the upper prism sheet exposed by the lower air gap is parallel to a surface of the lower prism sheet facing the upper prism sheet. delete According to claim 1,
A side surface of the upper prism sheet is exposed by the upper air gap. According to claim 1,
The backlight unit further includes a diffusion sheet positioned on a surface of the light guide plate facing the liquid crystal panel and a reflector plate positioned on a surface of the light guide plate facing the liquid crystal panel,
The lower prism sheet is positioned between the upper prism sheet and the diffusion sheet. According to claim 7,
A side surface of the lower prism sheet facing the light incident surface is vertically aligned with a side surface of the upper prism sheet. According to claim 7,
The area of the upper prism sheet is smaller than the area of the lower prism sheet. According to claim 1,
The mold frame includes a stepped portion overlapping an edge of the lower prism sheet and an edge of the upper prism sheet,
The side wall portion surrounds side surfaces of the lower prism sheet and side surfaces of the upper prism sheet on three surfaces of the light guide plate except for the light incident surface.

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