JP2007299716A - Illuminating device, electro-optical device and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a both-faces-display type electro-optical device that can be thinned. <P>SOLUTION: The electro-optical device is constituted by a first display panel, a second display panel, a light guide plate, and a light source. The second display panel is placed to be opposed to the first display panel. The light guide plate has a first output surface opposed to the first display panel and a second output surface opposed to the second display panel. In this condition, the light guide plate has its end face connected with the first output surface by a first inclined surface and connected with the second output surface by a second inclined surface, and a thickness between the first inclined surface and the second inclined surface is gradually more reduced as approach progresses from the end face to the first and second output surfaces. In this way, a thickness between the first output surface and the second output surface can be more reduced than a thickness of an ordinary rectangular light guide plate, thus making it possible to thin the electro-optical device. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a so-called double-sided display type electro-optical device.

  Recently, so-called double-sided display type mobile phones have become widespread. A double-sided display type electro-optical device is used for a double-sided display type mobile phone. For example, in a foldable mobile phone, a display unit (corresponding to the lid side in terms of structure) is generally attached to a main body unit provided with operation buttons so that it can be folded in a hinged manner. A large display panel is provided on the inner side (side facing the operation button) of the display unit, and a small display panel is provided on the outer side (rear side) of the display unit. That is, a large display panel and a small display panel are provided back to back. For example, a liquid crystal display panel is used as the large display panel and the small display panel. And the illuminating device is provided in the form inserted | pinched between these display panels. That is, the double-sided display type electro-optical device includes a large display panel, a small display panel, and an illumination device sandwiched between the display panels. The double-sided display type electro-optical device is often used in a mobile phone as described above, and therefore, it is required to be thinner.

  Patent Document 1 below describes a technique for reducing the thickness of a single-sided display type electro-optical device.

JP-A-2005-339956

  The present invention has been made in view of the above points, and an object thereof is to provide a double-sided display type electro-optical device that can be reduced in thickness.

  In one aspect of the present invention, an electro-optical device includes a first display panel, a second display panel disposed to face the first display panel, the first display panel, A light guide plate disposed between the second display panels and having a first emission surface facing the first display panel; a second emission surface facing the second display panel; and A light source for allowing light to enter from an end face, wherein the end face and the first exit face are connected by a first slope, and the end face and the second exit face are a second slope. The thickness between the first slope and the second slope is gradually reduced from the end face toward the first and second exit faces.

  The electro-optical device is, for example, a liquid crystal display device, and includes a first display panel, a second display panel, a light guide plate, and a light source. Here, an illumination device is constituted by the light guide plate and the light source. The first display panel and the second display panel are, for example, liquid crystal display panels. The second display panel is disposed to face the first display panel. The light guide plate has a first emission surface facing the first display panel and a second emission surface facing the second display panel. The light source is, for example, an LED (Light Emitting Diode), and makes light incident from an end face of the light guide plate. Here, in the light guide plate, the end surface and the first emission surface are connected by a first inclined surface, the end surface and the second emission surface are connected by a second inclined surface, and the first inclined surface, The thickness between the second slopes gradually decreases from the end face toward the first and second exit faces. By doing so, the thickness between the first emission surface and the second emission surface can be made thinner than the thickness of a general rectangular light guide plate, and the electro-optical device can be made thinner. Can do.

  In one aspect of the electro-optical device, an optical sheet is disposed on either the first emission surface or the second emission surface. Examples of the optical sheet include a diffusion sheet and a prism sheet. In the electro-optical device according to the aspect of the invention, the thickness between the first emission surface and the second emission surface is smaller than the thickness of a general rectangular light guide plate. And even if it is a case where an optical sheet is arrange | positioned on the said 2nd output surface, compared with a general electro-optical apparatus, thickness reduction can be achieved.

  In another aspect of the present invention, an electronic apparatus including the above-described electro-optical device in a display portion can be configured.

  In still another aspect of the present invention, the illumination device includes a light guide plate having a first emission surface and a second emission surface facing each other, and a light source that makes light incident from an end surface of the light guide plate, In the light guide plate, the end face and the first emission face are connected by a first slope, the end face and the second emission face are connected by a second slope, and the first slope and the second slope are connected. The thickness between the slopes gradually decreases from the end face toward the first and second exit faces. Thereby, thickness reduction of an illuminating device can also be achieved.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the present invention is applied to a liquid crystal display device.

[Liquid Crystal Display]
FIG. 1 is a side view showing a schematic configuration of a liquid crystal display device 100 according to the present embodiment. In FIG. 1, for convenience of explanation, each component is illustrated with a space therebetween, but actually, the liquid crystal display device 100 is configured in a state where they are stacked in the vertical direction in the drawing.

  The liquid crystal display device 100 is a so-called double-sided display type liquid crystal display device, and mainly includes an illumination device 9, a liquid crystal display panel 20, and a liquid crystal display panel 30. The illumination device 9 includes a light source unit 15 and a light guide plate 11. Liquid crystal display panels 20 and 30 are arranged above and below the light guide plate 11 of the illumination device 9. The light source unit 15 includes a plurality of LEDs 16 that are point light sources.

  The light L emitted from each LED 16 enters the light guide plate 11 from the end surface 11c, and changes its direction by repeating reflection on the upper and lower surfaces of the light guide plate 11, that is, the emission surfaces 11a and 11b facing each other, and the emission surface 11a. 11b are emitted to the outside as illumination lights La and Lb, respectively. In the light guide plate 11, the emission surface 11 a faces the liquid crystal display panel 20, and the emission surface 11 b faces the liquid crystal display panel 30. Therefore, the light La emitted from the emission surface 11a travels toward the liquid crystal display panel 20, and the light Lb emitted from the emission surface 11b travels toward the liquid crystal display panel 30.

  The liquid crystal display panel 20 corresponds to a main display panel in a double-sided display type mobile phone, and has a display area substantially the same as the light emitting area of the light guide plate 11. The liquid crystal display panel 20 is configured by laminating substrates 1a and 2a such as glass through a sealing material 3a to form a cell structure and enclosing the liquid crystal 4a therein. In the present invention, the structure of the liquid crystal display panel 20 is not limited to a specific one.

  Between the illumination device 9 and the liquid crystal display panel 20, for example, a diffusion sheet 12a and a prism sheet 13a are provided as optical sheets. The diffusion sheet 12a has a role of diffusing the light La emitted from the light guide plate 11 in all directions. The prism sheet 13a has a role of condensing the light La on the liquid crystal display panel 20, and has a shape in which a prism shape having a substantially triangular cross section is extended in one side direction (side direction perpendicular to the cross section). . The light La emitted from the light guide plate 11 passes through these optical sheets and then illuminates by passing through the liquid crystal display panel 20.

  On the other hand, the liquid crystal display panel 30 is a panel that is smaller than the liquid crystal display panel 20 and has a smaller display area than the liquid crystal display panel 20. The liquid crystal display panel 30 corresponds to a sub display panel (a small display panel provided on the back of the main display panel) in terms of a double-sided display type mobile phone. The liquid crystal display panel 30 is also configured by bonding substrates 1b and 2b made of glass or the like through a sealing material 3b and enclosing the liquid crystal 4b therein. In the present invention, the structure of the liquid crystal display panel 30 is not limited to a specific one.

  Between the liquid crystal display panel 30 and the light guide plate 10, for example, a diffusion sheet 12b and a prism sheet 13b are provided as optical sheets. The diffusion sheet 12 b diffuses the light Lb emitted from the light guide plate 11 in all directions, and the prism sheet 13 b collects the diffused light Lb and guides it to the liquid crystal display panel 30. Light Lb emitted from the light guide plate 11 is illuminated by passing through the liquid crystal display panel 30 after passing through these optical sheets.

(Structure of lighting device)
Next, the structure of the illumination device 9 according to the present embodiment will be described in detail. The illumination device 9 includes the light source unit 15 and the light guide plate 11 as described above. FIG. 2 is a perspective view of the light guide plate 11. FIG. 2 is a perspective view when the light guide plate 11 is viewed from the direction of the light source unit 15.

  As shown in FIG. 2, the light guide plate 11 has an end surface 11c and an exit surface 11a connected by a slope 11ac, an end surface 11c and an exit surface 11b connected by a slope 11bc, and the thickness between the slope 11ac and the slope 11bc is As it goes from the end surface 11c to the emission surfaces 11a and 11b, it has a shape that becomes gradually thinner. Therefore, the light L incident from the end surface 11c is accurately reflected on the inclined surfaces 11ac and 11bc and then reflected on the exit surfaces 11a and 11b, and the illumination lights La and Lb are respectively emitted from the exit surfaces 11a and 11b. To the outside.

  3A shows a side view of a general lighting device 29 to which an optical sheet is attached, and FIG. 3B shows a side view of the lighting device 9 according to the present embodiment to which an optical sheet is attached.

  As shown in FIG. 3A, the light guide plate 21 in the general lighting device 29 has, for example, a rectangular shape, and the thickness thereof is substantially the same as the thickness of the light emitting surface of the light source unit 15. Therefore, it is about 0,6 [mm]. Therefore, when the diffusion sheets 12a and 12b and the prism sheets 13a and 13b are attached to the light guide plate 21, the thickness of the lighting device 29 is about 1.0 [mm].

  On the other hand, as shown in FIG. 3B, in the light guide plate 11 in the illumination device 9 according to the present embodiment, the thickness on the end surface 11c is about 0.6 [mm], but the slope 11ac and the slope The thickness between 11bc has a shape which becomes thin gradually as it goes to the output surfaces 11a and 11b from the end surface 11c. Accordingly, the thickness between the emission surfaces 11a and 11b is about 0.45 to 0.5 [mm]. Therefore, the thickness of the illuminating device 9 when the diffusion sheet 12a and the prism sheet 13a are attached on the emission surface 11a and the diffusion sheet 12b and the prism sheet 13b are attached on the emission surface 11b is 0.9 [mm]. It becomes as follows.

  As can be seen from the above, in the illuminating device 9 according to the present embodiment, the light guide plate 11 includes the end surface 11c and the exit surface 11a connected by the inclined surface 11ac, and the end surface 11c and the exit surface 11b connected by the inclined surface 11bc. The thickness between 11ac and slope 11bc has a structure which becomes thin gradually as it goes to the output surfaces 11a and 11b from the end surface 11c. Thereby, the thickness between the output surfaces 11a and 11b in the light guide plate 11 can be reduced. Therefore, the lighting device 9 according to the present embodiment can be reduced in thickness as compared with the general lighting device 29 even when an optical sheet is attached. The liquid crystal display device 100 can be thinned.

  In the above-described embodiment, the liquid crystal display panel is exemplified as the display panel illuminated by the illumination device, but the present invention is not limited to this. A display panel other than the liquid crystal display panel may be used as long as the display panel is illuminated by transmitting light emitted from the illumination device. For example, a display panel such as an organic electroluminescence panel, a plasma display panel, or a field emission display can be used.

  Further, in the above-described embodiment, the optical sheet is configured such that the diffusion sheet and the prism sheet are attached to the output surface in this order, but the configuration of the optical sheet is not limited to this, and various configurations are possible. Needless to say.

[Electronics]
Next, a specific example of an electronic apparatus to which the liquid crystal display device 100 according to this embodiment can be applied will be described with reference to FIG.

  FIG. 4 shows a mobile phone 2000 which is an embodiment of the electronic apparatus according to the present invention. The cellular phone 2000 includes a main body 2001 having various operation buttons and a built-in microphone, and a display unit 2002 having a display screen and an antenna and a built-in speaker. The main body 2001 and the display 2002 are mutually connected. It is configured to be foldable. 4A shows a view when the mobile phone 2000 is opened, and FIG. 4B shows a view when the mobile phone 2000 is folded. The display unit 100 incorporates the above-described display device 100. The display screen 110 of the main-side liquid crystal display panel 20 is configured to be visible on the inner surface, and the sub-side liquid crystal display panel is disposed on the outer surface. 30 display screens 130 are configured to be visible.

It is a side view which shows the structure of the liquid crystal display device which concerns on this embodiment. It is a perspective view of the light-guide plate which concerns on this embodiment. It is sectional drawing of the illuminating device at the time of attaching an optical sheet. It is a figure which shows the example of the electronic device to which the liquid crystal display device of this embodiment is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 9 Illuminating device, 11 Light guide plate, 15 Light source part, 16 LED, 12a, 12b Diffusion sheet, 13a, 13b Prism sheet, 20, 30 Liquid crystal display panel, 100 Liquid crystal display device

Claims (4)

A first display panel;
A second display panel disposed opposite to the first display panel;
A first emission surface disposed between the first display panel and the second display panel and facing the first display panel; and a second emission surface facing the second display panel. A light guide plate having,
A light source for making light incident from an end surface of the light guide plate,
In the light guide plate, the end face and the first emission face are connected by a first slope, the end face and the second emission face are connected by a second slope, and the first slope and the second slope are connected. The electro-optical device is characterized in that the thickness between the inclined surfaces gradually decreases from the end surface toward the first and second emission surfaces.   The electro-optical device according to claim 1, wherein an optical sheet is disposed on at least one of the first emission surface and the second emission surface.   An electronic apparatus comprising the liquid crystal display device according to claim 1 in a display unit. A light guide plate having a first emission surface and a second emission surface facing each other;
A light source for making light incident from an end surface of the light guide plate,
In the light guide plate, the end face and the first emission face are connected by a first slope, the end face and the second emission face are connected by a second slope, and the first slope and the second slope are connected. The lighting device is characterized in that the thickness between the slopes gradually decreases from the end face toward the first and second exit faces.

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