JP2006098550A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display which can improve the visibility of the rotating reel arranged behind the liquid crystal display panel. <P>SOLUTION: This is a liquid crystal display which has a transparent liquid crystal display panel 2, having an effective display area with display elements in front of a rotating reel 110 arranged freely turnable, and a surface light source 15 provided between the liquid crystal display panel 2 and the rotating reel 110 for illuminating the liquid crystal display panel 2 from behind. The surface light source 15 has a light source 20, a hole 21A facing the rotating reel 110, and a lightguide 21 for guiding the light emitted from the light source 20, to the liquid crystal display panel 2. The end surface 21S along the hole 21A is formed into a curved surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device, and more particularly to a transmissive liquid crystal display panel and a liquid crystal display device including a surface light source device that illuminates the transmissive liquid crystal display panel.

  Liquid crystal display devices are utilized in various fields as display devices for OA equipment such as personal computers and information terminal equipment, taking advantage of features such as light weight, thinness, and low power consumption. In recent years, liquid crystal display devices are also used in gaming machines such as slot machines. A liquid crystal display panel mounted for use in a gaming machine is fitted, for example, over the entire display window of the casing (see, for example, Patent Document 1).

That is, a reel window is formed in the center of the liquid crystal display panel so that a lottery result based on the design of the rotating reel housed in the housing can be viewed from the outside. In such a gaming machine, when the display on the liquid crystal display panel is unnecessary, the driving of the liquid crystal display panel can be stopped so that the rotating reel on the back can be visually observed. Various images can be displayed around the rotating reel in a transparent state in a state where the rotating reel is visible.
JP 2000-308551 A

  The gaming machine having the above-described configuration includes a light emitting device. The emitted light from the light emitting device is reflected by a reflection plate inside the casing, illuminates the rotating reel housed inside the casing, and illuminates the liquid crystal display panel. Since the liquid crystal display panel displays an image by selectively transmitting illumination light from the back surface, even with such a configuration, there is no problem that visibility is deteriorated. However, since the rotating reel is observed from the front side (observer side) through the liquid crystal display panel, when illuminated from the back side, the front side is shaded, resulting in deterioration of visibility.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a liquid crystal display device capable of improving the visibility of a rotating reel disposed behind a liquid crystal display panel. is there.

A liquid crystal display device according to an aspect of the present invention
A transmissive liquid crystal display panel provided with an effective display portion arranged on the front side of a rotatable reel and arranged with a plurality of display pixels;
A surface light source device disposed between the liquid crystal display panel and the rotating reel and illuminating the liquid crystal display panel from the back side thereof, and a liquid crystal display device comprising:
The surface light source device includes a light source,
A light guide that has an opening facing the rotating reel and emits radiated light emitted from the light source toward the liquid crystal display panel;
The end face along the edge of the opening is formed as a curved surface.

  According to the present invention, it is possible to provide a liquid crystal display device capable of improving the visibility of a rotating reel disposed behind the liquid crystal display panel.

  Hereinafter, a liquid crystal display device according to an embodiment of the present invention, particularly a liquid crystal display device that can be used for gaming machines will be described with reference to the drawings.

  As shown in FIG. 1, the liquid crystal display device 1 includes a transmissive liquid crystal display panel 2 having a substantially rectangular flat plate shape. The liquid crystal display panel 2 includes a pair of substrates, that is, an array substrate 3 and a counter substrate 4, and a liquid crystal layer 5 held between them as a light modulation layer. The liquid crystal display panel 2 includes a rectangular effective display unit 6 corresponding to a display area for displaying an image. The effective display unit 6 is composed of a plurality of display pixels PX arranged in a matrix.

  In the effective display section 6, the array substrate 3 extends along the column direction of the display pixels PX and a plurality of scanning lines Y (1, 2, 3,..., M) extending along the row direction of the display pixels PX. A plurality of existing signal lines X (1, 2, 3,..., N), connected to the switching elements 7 and switching elements 7 arranged for each display pixel PX in the vicinity of the intersection of the scanning lines Y and the signal lines X. The pixel electrode 8 and the like are provided.

  The switching element 7 is composed of a thin film transistor (TFT) or the like. The gate electrode 7G of the switching element 7 is electrically connected to the corresponding scanning line Y (or formed integrally with the scanning line). The drain electrode 7D of the switching element 7 is electrically connected to the corresponding signal line X (or formed integrally with the signal line). The source electrode 7S of the switching element 7 is electrically connected to the pixel electrode 8 of the corresponding display pixel PX.

  The counter substrate 4 includes a counter electrode 9 and the like common to all the display pixels PX in the effective display unit 6. The pixel electrode 8 and the counter electrode 9 are formed of a light-transmitting conductive material such as ITO (Indium Tin Oxide). The array substrate 3 and the counter substrate 4 are arranged with the pixel electrode 8 and the counter electrode 9 facing each other, and a gap is formed between them. The liquid crystal layer 5 is formed of a liquid crystal composition sealed in the gap between the array substrate 3 and the counter substrate 4.

  In the liquid crystal display panel 2, a pair of polarizing plates PL 1 and PL 2 whose polarization directions are set in accordance with the characteristics of the liquid crystal layer 5 are provided on the outer surface of the array substrate 3 and the outer surface of the counter substrate 4.

  In the color display type liquid crystal display device, the liquid crystal display panel 2 includes a plurality of types of display pixels, for example, a red pixel that displays red (R), a green pixel that displays green (G), and a blue that displays blue (B). Has pixels. That is, the red pixel includes a red color filter that transmits light having a red main wavelength. The green pixel includes a green color filter that transmits light having a green dominant wavelength. The blue pixel includes a blue color filter that transmits light having a blue main wavelength. These color filters are arranged on the main surface of the array substrate 3 or the counter substrate 4.

  The liquid crystal display panel 2 having such a configuration is disposed between a rectangular frame bezel cover 11 and a backlight 15 as a surface light source device. That is, the backlight 15 is integrated with the bezel cover 11 together with the liquid crystal display panel 2 with the surface thereof facing the back side (array substrate side) of the liquid crystal display panel 2. Illuminate from the side.

  A driver circuit 12 that supplies a drive signal to the liquid crystal display panel 2 is electrically connected to one side edge of the liquid crystal display panel 2 via a flexible printed wiring board 13. The driver circuit 12 is arranged on the back side of the backlight 15 by curving the printed wiring board 13.

  As illustrated in FIGS. 1 to 3, the backlight 15 includes a light source unit 20, a light guide 21, and the like. The light source unit 20 includes a cold cathode tube 22 and a lamp reflector 23 as a light source. That is, the cold cathode tube 22 is an elongated cylindrical tubular light source extending in the longitudinal direction of the substantially rectangular light guide 21. The lamp reflector 23 reflects the radiated light emitted from the cold cathode tube 22 toward the light guide 21, and is disposed so as to surround the cold cathode tube 22.

  The light guide 21 is formed of a resin material such as an acrylic resin or a polycarbonate resin having light transmittance. Here, the light guide 21 is formed in a substantially rectangular shape. The light guide 21 includes a first main surface 21b facing the liquid crystal display panel 2, a second main surface 21d facing the first main surface 21b, and the first main surface 21b and the second main surface 21d. The first side surface 21a and the second side surface 21c are connected to each other. The first side surface 21a and the second side surface 21c face each other and are each formed in a rectangular shape.

  In this embodiment, the light source unit 20 is disposed along a pair of long sides 21 </ b> L of the light guide 21. That is, the cold cathode tubes 22 are respectively disposed so as to face the first side surface 21 a and the second side surface 21 c along the long side 21 </ b> L of the light guide 21 substantially in parallel. That is, the first side surface 21a and the second side surface 21c of the light guide correspond to a light incident surface on which the emitted light from the cold cathode tube 22 is incident.

  The light guide 21 having such a configuration can propagate linear radiation light from the cold cathode tube 22 incident through the first side surface 21a and the second side surface 21c, and can be emitted from the first main surface 21b. . That is, the first main surface 21 b of the light guide 21 corresponds to an emission surface that emits light incident on the light guide 21.

  The substantially rectangular optical sheet 24 is disposed so as to cover the first main surface 21 b of the light guide 21. The optical sheet 24 gives a predetermined optical characteristic to the outgoing light emitted from the first main surface 21b of the light guide 21. For example, the optical sheet 24 collects the outgoing light from the first main surface 21b. And a diffusion sheet for diffusing the light emitted from the first main surface 21b.

The substantially rectangular optical sheet 25 is arranged so as to cover the second main surface 21 d of the light guide 21. The optical sheet 25 is a reflection sheet that reflects the emitted light leaking from the second main surface 21 d of the light guide 21 toward the light guide 21 again.
The light source unit 20, the light guide 21, and the optical sheets 24 and 25 are accommodated in a substantially rectangular frame 30.

  The liquid crystal display device configured as described above operates as follows. That is, electric energy is supplied to the cold cathode tubes 22 of the pair of light source units 20 to cause the cold cathode tubes 22 to emit light. The linear radiation emitted from the cold cathode tubes 22 is reflected by the inner surface of the lamp reflector 23 covering the cold cathode tubes 22, and directed toward the first side surface 21a and the second side surface 21c of the light guide 21, respectively. Is derived. Incident light that has entered from the first side surface 21 a and the second side surface 21 c of the light guide 21 propagates through the light guide 21 toward the first main surface 21 b and the second main surface 21 d of the light guide 21. Refracted or reflected. The emitted light emitted from the second main surface 21 d of the light guide 21 is reflected again toward the inside of the light guide 21 by the optical sheet 25.

  The emitted light emitted from the first main surface 21b of the light guide 21 is given predetermined optical characteristics such as being appropriately condensed or moderately diffused when passing through the optical sheet 24. Thereby, the brightness | luminance of the emitted light radiate | emitted from the 1st main surface 21b of the light guide 21 is improved, and it is made uniform.

  Illumination light from the backlight 15, that is, light that has passed through the optical sheet 24 is led out to the back side of the liquid crystal display panel 2. The illumination light derived to the liquid crystal display panel 2 selectively transmits through the effective display unit 6 of the liquid crystal display panel 2. Thereby, an image is displayed on the effective display section 6 of the liquid crystal display panel 2.

  Next, the liquid crystal display device 1 used for a gaming machine such as a slot machine will be described. That is, as shown in FIGS. 1 and 3, the gaming machine includes a rotating reel 110 that is rotatably arranged inside the housing 100. The rotary reel 110 includes a plurality of, for example, three cylindrical reel bodies 111 that can rotate around a rotation axis O, and a belt-like reel tape 112 that is attached to the cylindrical surface of the reel body 111. . The reel tape 112 has a plurality of patterns arranged at equal intervals.

  The liquid crystal display device 1 is disposed on the front side (that is, the observer side) of the rotating reel 110 inside the housing 100. That is, the liquid crystal display panel 2 is disposed on the front side of the rotating reel 110, and the backlight 15 is disposed between the liquid crystal display panel 2 and the rotating reel 110. The housing 100 includes a window portion 102 that allows an image displayed on the liquid crystal display device 1 to be viewed, and the window portion 102 includes a protective plate 103 having a light transmission property such as a glass plate.

  The backlight 15 mounted on such a liquid crystal display device 1 has an opening 15 </ b> A corresponding to the position where the rotary reel 110 is disposed at the approximate center thereof. That is, the light guide 21 has an opening 21 </ b> A that faces the rotating reel 110. Similarly, the optical sheet 24 has an opening 24A at a position corresponding to the opening 21A. Further, the optical sheet 25 similarly has an opening 25A at a position corresponding to the opening 21A. Such an opening 15 </ b> A of the backlight 15 has a substantially rectangular shape, and allows a predetermined number of patterns on the rotary reel 110 located behind the backlight 15 to be viewed.

  Thereby, the weight of the light guide 21 is reduced, and the liquid crystal display device 1 can be reduced in weight. Further, since the rotary reel 110 can be viewed without using the backlight 15, the visibility of the rotary reel 110 can be improved.

  By the way, in the liquid crystal display panel 2 described above, when an image is displayed on the effective display unit 6, the luminance of the region located on the first main surface 21 b of the light guide 21 and the region located on the opening 21 </ b> A is reduced. The difference may be visible. That is, since the region located on the first main surface 21b is efficiently illuminated by the radiated light from the cold cathode tube 22 guided by the light guide 21, relatively high luminance can be obtained. On the other hand, since it is difficult to guide the emitted light from the cold cathode tube 22 to the region located on the opening 21A, the luminance in this region tends to be relatively low.

  For this reason, due to these luminance differences, the edge 21E that defines the opening 21A of the light guide 21 is easily visually recognized. The edge 21E is the edge of the opening 21A in a plane parallel to the main surface (for example, the first main surface 21b or the second main surface 21d) of the light guide 21 as shown in FIG. It corresponds to.

  Therefore, as shown in FIGS. 1 to 5, in the light guide 21 according to this embodiment, the end surface 21S along the edge 21E of the opening 21A is formed by a curved surface. More specifically, the light guide 21 has a tapered portion 21T around the opening 21A, the thickness of which gradually decreases toward the opening 21A. The thickness here corresponds to the thickness along the normal direction N of the first main surface 21b (or the second main surface 21d) of the light guide 21. In particular, in the example shown in FIGS. 4 and 5, the opening 21A has a substantially rectangular shape, and the entire tapered portion 21T is formed by a curved surface extending along each side of the opening 21A. At this time, in the cross section orthogonal to the first main surface 21b of the light guide 21, the tapered portion 21T has an arbitrary curved shape.

  In the tapered portion 21T having such a shape, illumination light having gradation can be formed. That is, in the thick portion of the tapered portion 21T that is separated from the opening 21A, the emitted light from the cold cathode tube 22 can be efficiently guided, and a relatively high luminance can be obtained. Further, a relatively low luminance is obtained at the thin portion near the tip portion TE in the tapered portion 21T. Since the thickness gradually decreases from the thick portion to the thin portion, the brightness gradually decreases from the thick portion to the thin portion in the tapered portion 21T, and illumination light having gradation is formed. At this time, the difference between the luminance of the illumination light on the thin portion and the luminance of the illumination light on the opening 21A can be reduced.

  Further, in the tapered portion 21T, at least the tip portion TE is formed with a curved surface. This tip portion TE corresponds to the vicinity of the edge 21E portion. For this reason, the light incident from the light incident surfaces 21a and 21c facing the front end portion TE can be collected by the front end portion TE. That is, it is possible to give a lens action to the tip portion TE of the tapered portion 21T. This makes it possible to illuminate the opening 21A with the light condensed at the tip TE, and further reduce the difference between the luminance of the illumination light on the thin portion and the luminance of the illumination light on the opening 21A. be able to.

  Therefore, according to the light guide 21 having the above-described structure, when an image is displayed on the effective display unit 6, the luminance in the area near the edge 21E of the opening 21A is averaged, and the edge 21E is hardly visible. . Thereby, it is possible to improve the display quality of the image.

  In the example shown in FIGS. 4 and 5, the case where the entire tapered portion 21T is formed with a curved surface has been described, but the shape of the curved surface is not particularly limited. For example, the tapered portion 21T may be formed of a cylindrical surface extending along each side of the opening 21A, as shown in FIG. At this time, the central axis of the cylindrical surface is parallel to each side defining the rectangular opening 21A, and in the cross section orthogonal to the first main surface 21b of the light guide 21, the tapered portion 21T has a semicircular shape. Become. That is, the first main surface 21b located on the liquid crystal display panel 2 side of the light guide 21 and the second main surface 21d located on the rotary reel 110 side of the light guide 21 are connected by the cylindrical surface CS. Even with such a structure, the same effects as those of the above-described embodiment can be obtained.

  Further, as shown in FIG. 7, the tapered portion 21 </ b> T includes a first flat surface T <b> 1 extending from the first main surface 21 b located on the liquid crystal display panel 2 side of the light guide 21, and a rotating reel of the light guide 21. It may be formed of a second flat surface T2 extending from the second main surface 21d located on the 110 side and a curved surface T3 connecting the first flat surface T1 and the second flat surface T2. Even with such a structure, the same effects as those of the above-described embodiment can be obtained.

  As described above, according to the liquid crystal display device usable for the gaming machine according to this embodiment, the opening is formed in the light guide of the backlight corresponding to the position where the rotating reel is provided. . Thereby, the weight of the light guide is reduced, and the weight of the liquid crystal display device can be reduced. Further, since the rotating reel can be viewed without going through the backlight, the visibility of the rotating reel can be improved.

  In addition, the light guide has a tapered portion around the opening that gradually decreases in thickness toward the opening, and at least the tip of the tapered portion is formed with a curved surface. When the image is displayed on the effective display portion, the edge of the opening portion becomes difficult to be visually recognized. Thereby, it is possible to improve the display quality of the image.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the gist of the invention in the stage of implementation. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

FIG. 1 is an exploded perspective view schematically showing the structure of a liquid crystal display device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view schematically showing a structure of a backlight mounted on the liquid crystal display device shown in FIG. FIG. 3 is a cross-sectional view schematically showing the structure of a liquid crystal display device used in a gaming machine. FIG. 4 is a plan view schematically showing the structure of a light guide applicable to the backlight shown in FIG. FIG. 5 is a cross-sectional view schematically showing the structure of the light guide shown in FIG. FIG. 6 is a cross-sectional view schematically showing the structure of a light guide applicable to the backlight shown in FIG. FIG. 7 is a cross-sectional view schematically showing the structure of a light guide applicable to the backlight shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device, 2 ... Liquid crystal display panel, 15 ... Backlight (surface light source device), 15A ... Opening part, 20 ... Light source part, 21 ... Light guide, 21A ... Opening part, 21E ... Edge, 21S ... End face 21T ... taper portion, 21a ... first side surface, 21b ... first main surface, 21c ... second side surface, 21d ... second side surface, 22 ... cold cathode tube (light source), 23 ... lamp reflector, 24 ... optical sheet, 25 ... Optical sheet, 30 ... Frame, 100 ... Housing, 110 ... Rotating reel, 111 ... Reel body, 112 ... Reel tape

Claims (5)

A transmissive liquid crystal display panel provided with an effective display portion arranged on the front side of a rotatable reel and arranged with a plurality of display pixels;
A surface light source device disposed between the liquid crystal display panel and the rotating reel and illuminating the liquid crystal display panel from the back side thereof, and a liquid crystal display device comprising:
The surface light source device includes a light source,
A light guide that has an opening facing the rotating reel and emits radiated light emitted from the light source toward the liquid crystal display panel;
An end face along the edge of the opening is formed as a curved surface. The light guide has a tapered portion around the opening, the thickness of which gradually decreases toward the opening,
The liquid crystal display device according to claim 1, wherein at least a tip portion of the tapered portion is a curved surface. The opening is substantially rectangular,
The liquid crystal display device according to claim 2, wherein the tapered portion is formed of a cylindrical surface extending along each side of the opening.   The tapered portion extends from a first flat surface extending from a first main surface located on the liquid crystal display panel side of the light guide and a second main surface located on the rotating reel side of the light guide. 3. The liquid crystal display device according to claim 2, wherein the liquid crystal display device is formed by a protruding second flat surface and a curved surface connecting the first flat surface and the second flat surface.   The said surface light source device is provided with the optical sheet which provides a predetermined | prescribed optical characteristic to the emitted light radiate | emitted from the said light guide between the said light guide and the said liquid crystal display panel. A liquid crystal display device according to 1.

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