JP2008209810A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve sensitivity of receiving external light of a liquid crystal display device having an external light sensor at the end of the effective display region. <P>SOLUTION: When a light-receiving element as an external light sensor is formed on an active matrix substrate that drives pixels, a light-shielding film having an opening that enables the external light to enter the light-receiving element is placed on a counter substrate above the light-receiving element, and a light-shielding tape disposed between the active matrix substrate and a molded component that holds the gap between the structure and a structure on the back face of the substrate is further extended to a position overlapping the external light sensor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device in which an optical sensor is provided in a seal space, and particularly to a light shielding technique thereof.

  As a related art relating to a liquid crystal display device provided with a light shielding tape, there is Patent Literature 1.

  Patent Document 1 discloses a liquid crystal display device in which a light-shielding tape is attached to the back surface of a TFT substrate from the end toward the pixel. Specifically, by arranging a light-shielding film on the backlight unit side surface of the region where the sealing material and the black matrix do not overlap on the backlight side surface of the substrate on the backlight side, It is supposed that light leakage from the backlight unit that leaks to the display surface side from a region that does not overlap with the black matrix can be blocked.

  As a related art relating to a liquid crystal display device equipped with an external light sensor, there is Patent Document 2. This publication describes that a light-shielding film having an opening is provided inside the counter substrate above the external light sensor, and that the external light sensor is composed of a bottom gate type TFT and is shielded by the bottom gate.

JP 2002-139725 A JP 2000-131137 A

  In Patent Document 1, no consideration is given to the case where the light receiving element is formed on the TFT substrate.

  In Patent Document 2, light is shielded by the bottom gate, and there is no light shielding member when the top gate is used. Further, the light shielding member only considers the light shielding of the optical sensor. Moreover, only light shielding by the structure inside a board | substrate is described.

  In other words, in the conventional technology, the light shielding structure of the liquid crystal display device equipped with the optical sensor has not been a structure that can efficiently shield light.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device that can improve brightness and control brightness while improving the light shielding efficiency of a light shielding member with respect to light emitted from a light source irradiated from the back surface of an external light sensor.

  In one embodiment of the present invention, when a light receiving element to be an external light sensor is formed on an active matrix substrate for driving a pixel, a light shielding film having an opening is disposed above the light receiving element of the counter substrate, and There is a type in which a light-shielding tape arranged between a mold part that holds a gap between components outside the active matrix substrate such as a light source or a diffusion film is arranged up to a position overlapping with an external light sensor.

  By the above means, it is possible to simplify the manufacturing process by using an existing light shielding member. In addition, when a separate light shielding member is provided, there may be a gap between the light shielding tape around the substrate and the light shielding tape on the back side of the external light sensor, but light from the light source entering through the gap can also be shielded. Therefore, the visibility under external light is improved.

  Examples will be described below.

  FIG. 1 is an exploded perspective view showing the overall configuration of the liquid crystal display device of the present invention.

  PNL is a liquid crystal display panel, DRV is a drive circuit chip, SHD is an upper frame, MLD is a resin molded mold, PZS is a diffusion prism sheet, GLB is a light guide plate, LED is a light emitting diode element, RFS is a reflection sheet, and FPC-L is A flexible printed circuit board for a light source, PZG is a prism groove, CDL is an upper surface arc cross section groove, BTL is a lower surface triangular cross section groove, and ACD is a light incident surface arc cross section groove.

  The liquid crystal display panel PNL includes two substrates. The main surface (inner surface) of the first substrate SUB1 includes pixel electrodes arranged in a matrix for each pixel, a thin film transistor switch TFT that drives the pixel electrode, and a light receiving element PD. The main surface (inner surface) of the second substrate SUB2 includes a color filter CF corresponding to the pixels and a black matrix BM so as to cover the periphery and the outer periphery. The first substrate and the second substrate are sandwiched by a sealing material disposed between the two substrates so as to surround the effective display area, and a liquid crystal layer is enclosed in a space sandwiched between the two substrates and the sealing material. ing. A drive circuit chip (IC chip) DRV is disposed on one of the two glass substrates. The drive circuit chip DRV supplies a signal and power to the liquid crystal display panel PNL and the light receiving element PD, and changes the magnitude of the luminance signal or the backlight brightness depending on the detection value of the light receiving element PD.

  The liquid crystal display panel PNL is sandwiched from above and below in FIG. 1 by an upper frame SHD made of a metal frame and a resin-molded mold MLD. However, if the upper frame SHD can be fixed to the liquid crystal panel PNL, a tape or the like can be substituted and omitted.

  Although not shown, a light-shielding tape TAPE having an opening is disposed between the liquid crystal display panel PNL and the mold MLD. This light-shielding tape TAPE has a function as a buffer material that relieves the force applied from the front side of the liquid crystal display panel PNL and a function that blocks light irradiated from the light-emitting diode element LED to the light-receiving element PD. Details will be described later.

  On the lower side (rear surface) of the mold part MLD, at least one (here, four) light-emitting diode elements LED which are arranged on the side surfaces of the diffusion prism sheet PZS, the light guide plate GLB, and the light guide plate GLB, An optical unit composed of a reflection sheet RFS installed below the light guide plate GLB is installed. Instead of this reflection sheet, a reflection film such as silver may be directly disposed under the light guide plate GLB by vapor deposition or the like.

  The drive circuit chip DRV is supplied with display data, timing signals, power, and the like from an external circuit (information processing apparatus) (not shown) through the flexible printed circuit FPC.

  Further, the light emitting diode element LED is mounted on the light source flexible printed circuit FPC-L, and is disposed close to or in close contact with the light incident surface of the light guide plate GLB.

  The prism sheet PZS is a downward prism sheet having a prism groove PZG on the lower surface. A number of upper surface arc section grooves CDL are formed on the upper surface of the light guide plate GLB, and a number of lower surface triangular section grooves BTL extending in a direction perpendicular to the upper surface arc section groove CDL are formed on the lower surface. On the light exit surface of the light guide plate GLB, a light entrance surface arc-section groove ACD is formed. The light emitting diode element LED is disposed at a position facing the side surface of the light guide plate GLB, is reflected by the reflection sheet RFS, and exits to the liquid crystal display panel PNL as in-plane uniform light.

  FIG. 2 shows a top view of the upper frame SHD.

  The upper frame SHD has a rectangular opening surrounding the effective display area AR and the light receiving element PD.

  FIG. 3 shows a top view of the liquid crystal display panel PNL (the flexible printed circuit FPC is omitted).

  As described above, the liquid crystal display panel PNL includes the first substrate SUB1 and the second substrate SUB2, and is bonded by the seal material SEAL arranged in a frame shape.

  The first substrate SUB1 includes an effective display area AR and an external light sensor arranged outside the effective display area AR.

  In the effective display area, pixels PIX are arranged in a matrix, and each pixel electrode and a thin film transistor which is a switch for controlling voltage for each pixel electrode are provided.

  The external light sensor includes a light receiving element PD that converts the intensity of external light into an electrical signal.

  As described above, the pixel electrode, the thin film transistor, and the light receiving element PD are formed on the glass TFT substrate SUB1.

  In addition, a color filter CF and a black matrix BM are formed on the second substrate SUB2.

  Liquid crystal is sealed in a sealing space between the first substrate SUB1 and the second substrate SUB2.

  In this embodiment, since a so-called VA method is assumed, counter electrodes corresponding to the respective pixel electrodes are formed on the second substrate, but the details are omitted.

  Although not shown, polarizing plates are attached to both outer surfaces of the first substrate SUB1 and the second substrate SUB2.

  FIG. 4 shows a cross-sectional view of a position corresponding to A-B in a liquid crystal display device that does not have an external light sensor that we have prototyped.

  FIG. 5 is a cross-sectional view taken along the line AB in the liquid crystal display device of this example.

  The difference between FIG. 4 and FIG. 5 is that the planar position of the black matrix opening BMO and the planar position of the light receiving element PD overlap, and the light shielding tape TAPE between the liquid crystal display panel PNL and the mold part MLD The light-receiving element PD is shielded by one light-shielding tape TAPE so as to extend from the end of one substrate SUB1 to the effective display area AR side.

  Thus, by extending the light-shielding tape TAPE, the amount of light received from the back surface (light guide plate GLB side) of the light-receiving element PD can be reduced as compared with the case where the light-shielding tape TAPE is separated and arranged. The ratio of outdoor light increases. By performing feedback control of the detection value to the output to the backlight, more accurate luminance control is possible, and a liquid crystal display device having excellent visibility even under external light can be provided.

  This also makes it possible to widen the light shielding tape that shields the light receiving element PD, so that the light shielding tape TAPE can be easily supported by the mold part MLD. Therefore, the mold part MLD is not necessarily arranged below the light receiving element. A good structure can be adopted. Further, since the support area of the light shielding tape can be increased, the probability of natural peeling is reduced, and conversely, if the liquid crystal display panel PNL is defective, it is peeled off at the same time. Production efficiency is also improved.

FIG. 1 is an exploded perspective view showing the overall configuration of the liquid crystal display device of the present invention. FIG. 2 is a top view of the upper frame SHD of FIG. FIG. 3 is a top view of the liquid crystal display panel PNL (the flexible printed circuit FPC is omitted). 4 is a cross-sectional view of a position corresponding to A-B in FIG. 3 in a liquid crystal display device without an external light sensor. FIG. 5 is a cross-sectional view taken along the line AB in the liquid crystal display device of this example.

Explanation of symbols

PNL ... liquid crystal display panel, SHD ... upper frame, MLD ... mold, PZS ... prism sheet, GLB ... light guide plate, LED ... light emitting diode element, RFS ... reflection sheet, DRV ... Drive circuit chip, FPC ... Flexible printed circuit, FPC-L ... Flexible printed circuit for light source, PZG ... Prism groove, CDL ... Upper surface arc cross-section groove are formed. ..Lower surface triangular cross section groove, ACD...

Claims (2)

A liquid crystal panel, a mold part with an opening, a diffusion prism sheet, a light source, and a light shielding tape,
LCD panel
A first substrate having an inner surface with a pixel electrode and a thin film transistor for controlling a voltage applied to the pixel electrode;
A second substrate having a color filter and a black matrix on its inner surface;
A sealing material for sandwiching between the first substrate and the second substrate;
A liquid crystal layer sealed between the first substrate and the second substrate;
Have
In a liquid crystal display device having an opening of a mold component interposed between the outer surface of the first substrate and the diffusion prism sheet, and having a light shielding tape between the first substrate and the mold component,
The first substrate includes a light receiving element on an inner surface,
In a planar position viewed from the normal direction to the second substrate,
An opening of a black matrix is disposed above the light receiving element,
The liquid crystal display device, wherein the light shielding tape extends from an end of the first substrate to the light receiving element. A liquid crystal panel, a mold part with an opening, a diffusion prism sheet, a light source, and a light shielding tape,
LCD panel
A first substrate having an inner surface with a pixel electrode and a thin film transistor for controlling a voltage applied to the pixel electrode;
A second substrate having a color filter and a black matrix on its inner surface;
A sealing material for sandwiching between the first substrate and the second substrate;
A liquid crystal layer sealed between the first substrate and the second substrate;
Have
In a liquid crystal display device having an opening of a mold part interposed between the outer surface of the first substrate and the diffusion prism sheet, and having a light shielding tape between the first substrate and the mold part,
The first substrate includes a light receiving element on an inner surface,
The liquid crystal display device, wherein the light shielding tape is attached so as to extend from an end of the first substrate to the back of the light receiving element.

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