JP2007141596A - Illumination device, electro-optical device, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination device which can be reduced in its thickness and size without worsening utilization efficiency and brightness distribution of light, and an electro-optical device provided with the same. <P>SOLUTION: The illumination device 110 comprises a light guide plate 112 having a flat light irradiation face 112b, and a light source 111 having a light emission face arranged so as to face an end face 112a of the light guide plate, and constituted so that the light emitted from the light source is incident from the end face into the light guide plate, propagated in the light guide plate, and irradiated from the light irradiation face. An area, increasing its thickness toward the end face is formed in a range of a part facing the end face, and a light axis 111x of the light source is arranged so as to slant against a back face 112c located at opposite side of the light irradiation face. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an illuminating device, an electro-optical device, and an electronic apparatus, and more particularly to a structure of an illuminating device including a light guide plate and a light source disposed to face an end surface of the light guide plate.

  In general, as shown in FIG. 8, the liquid crystal display is formed by bonding a pair of substrates 21 and 22 through a sealing material 23 and enclosing a liquid crystal 24 therebetween. Polarizing plates 25 and 26 are disposed on the outer surface. In a display device configured using such a liquid crystal display body 20, a backlight is often disposed behind the liquid crystal display body 20 so that the display can be visually recognized using illumination light from the backlight. Various backlights equipped with light sources such as cold cathode tubes and LEDs are known. In particular, in a display device that requires a reduction in thickness, as a backlight, a sidelight-type backlight including a light guide plate having a planar light emitting surface and a light source disposed opposite to an end surface of the light guide plate. Is used (see, for example, Patent Document 1 below).

In the sidelight type backlight described above, by forming various optical structures on the front and back surfaces of the light guide plate, or by arranging a light diffusing plate, a light condensing plate, etc. on the light output surface of the light guide plate, It is intended to make the luminance uniform on the light exit surface and to optimize the light exit angle distribution of the illumination light.
JP-A-11-224058

  However, since the above-described backlight is based on the premise that a light guide plate having a thickness larger than that of the light source is used, the thickness of the backlight cannot be reduced, and as a result, the thickness of the entire electro-optical device is reduced. There is a problem that cannot be done. For example, the light source unit 3 of Patent Document 1 has a structure in which a lamp holder 7 that also serves as a reflection plate is disposed around a lamp (cold cathode tube) 5, and thus has a thick structure. Also, it has a thickness corresponding to such a thick structure. In such a structure, the thickness of the backlight is at least about 10 mm, and the thickness cannot be reduced to several millimeters or less.

  For example, in recent liquid crystal display bodies, it has become possible to form a total thickness of about 1 to 1.5 mm by reducing the thickness of a glass substrate. Therefore, it is difficult to reduce the thickness of the entire display device. In the sidelight type backlight, the light guide plate is mainly disposed on the liquid crystal display body, but the thickness of the light guide plate is set to the light source plate so as not to reduce the efficiency of taking light into the light guide plate. Since it is necessary to correspond to the thickness, it is difficult to reduce the thickness of the light guide plate because it is difficult to reduce the thickness of the light source.

  Therefore, as shown in FIG. 8, a light source 11 composed of an LED or the like, a light guide plate 12 having an end surface 12 a and a planar light emission surface 12 b facing the light source 11, a reflection plate 13, a light diffusion plate 14, a light collecting plate 15 16 and a backlight (illumination device) 10 having a wiring substrate 17 on which the light source 11 is mounted, a portion of the upper surface of the light guide plate 12 adjacent to the end surface 12a side of the light emitting surface 12b configured in a planar shape. A method is conceivable in which the inclined edge surface 12d is formed so that the thickness in the vicinity of the end surface 12a of the light guide plate 12 is gradually increased toward the end surface 12a rather than the thickness of the flat region where the light emitting surface 12b is formed.

  In the backlight 10, the end surface 12 a can have a thickness substantially corresponding to the light emission surface 11 a of the light source 11, so that the light from the light source 11 can be efficiently taken into the light guide plate 12 and the liquid crystal display body. Since the light guide plate 12 can be thinly formed in the flat region provided with the light emitting surface 12b overlapping the 20 display regions A, the entire display device can be thinned without being restricted by the thickness of the light source 11. There is an advantage that can be. Note that the inclination angle of the inclined edge surface 12d shown in FIG. 8 is drawn to about 30 degrees in the drawing, but this is emphasized for easy understanding of the structure, and is actually about several degrees at most. Seems to be desirable.

  However, even in the backlight 10 described above, there is no problem if there is no significant difference between the thickness of the light source 11 and the thickness of the light emitting surface formation region of the light guide plate 12, but the difference in thickness becomes large. The inclination angle of the inclined edge surface 12d is increased, whereby the light from the light source 11 is liable to leak from the inclined edge surface 12d to the outside, so that the efficiency of taking light into the light guide plate 12 is reduced, or the display area A There is a problem that a phenomenon (eyeball phenomenon) in which the portion on the light source 11 side becomes higher in luminance than the other portion occurs. In addition, when the difference in thickness is increased, a method of securing the thickness of the end surface 12a by increasing the width of the inclined edge surface 12d instead of increasing the inclination angle of the inclined edge surface 12d can be considered. In this method, since the protruding amount of the portion (frame region) outside the display area A is increased, the planar size of the illumination unit is increased, which is contrary to the downsizing of the apparatus.

  Therefore, the present invention solves the above-mentioned problems, and the problem is that the lighting device can be reduced in thickness and size without deteriorating the light use efficiency and the luminance distribution, and the same is provided. Another object is to provide an electro-optical device.

  In view of such a situation, the illumination device of the present invention includes a light guide plate having a planar light emission surface, and a light source having a light emission surface disposed to face an end surface of the light guide plate, and the light source In the illuminating device configured such that the light emitted from the light enters the light guide plate from the end surface, propagates through the light guide plate, and is emitted from the light output surface, the light guide plate includes at least the light guide plate. A region where the thickness increases toward the end surface is provided in a partial range in a direction toward the end surface, and the optical axis of the light source is installed to be inclined to the surface opposite to the light emitting surface. .

  According to the present invention, the optical axis of the light source is installed to be inclined to the surface opposite to the light exit surface of the light guide plate, so that the distribution peak of the light emitted from the light source is relative to the light exit surface of the light guide plate. Since it is set in an oblique direction inclined to the opposite side (back side), even if the thickness of the light emitting surface formation region of the light guide plate is made thinner than the thickness of the light emitting surface of the light source, It is possible to suppress a decrease in the efficiency of taking in the light plate and to prevent a region having a high luminance (eyeball region) from being formed in a portion near the light source on the light exit surface. In addition, since the light guide plate is provided with a region whose thickness increases toward the end surface in at least a partial range in the direction toward the end surface, the thickness of the end surface facing the light source can be increased. The efficiency of taking light into the light plate can be increased.

  In this invention, it is preferable that the said light-guide plate has the light-incidence area | region where thickness increases gradually toward the said end surface in the said end surface side of the said light-projection surface. According to this, by providing the light incident area whose thickness gradually increases toward the end face on the end face side of the light guide plate, the thickness of the light emission surface of the light source is the formation area (light emission area) of the light output face of the light guide plate. Even when it is thicker, it is possible to increase the efficiency of taking light into the light guide plate.

  In the present invention, an inclined surface for gradually increasing the thickness toward the end surface is formed in the light incident region, and the inclined surface is provided adjacent to the end surface side of the light emitting surface. preferable. By providing an inclined surface formed in the light incident area adjacent to the end face side of the light emitting surface, a protruding portion for forming the thickness of the light incident area on the surface opposite to the light emitting surface of the light guide plate Therefore, when various display bodies (for example, electro-optic control bodies such as a liquid crystal display body) are arranged on the light emitting surface, the entire display device can be more efficiently thinned. In particular, the inclined surface is preferably a surface (an inclined edge surface) formed at an edge adjacent to the end surface in that the planar size of the light guide plate can be reduced.

  In the present invention, it is preferable that an inclination angle of the optical axis with respect to the light exit surface is equal to or less than an inclination angle of the inclined surface. By making the inclination angle of the optical axis of the light source equal to or less than the inclination angle of the inclined surface, not only can the angle of the optical axis with respect to the edge surface be reduced to prevent light leakage from the inclined surface, but also light emission of the light guide plate Since an increase in the angle of the optical axis with respect to the surface opposite to the surface can be suppressed, an increase in luminance on the light source side of the light emitting surface can be suppressed, and uniformity of luminance on the light emitting surface can be improved. In particular, it is desirable that the inclination angle of the optical axis is smaller than the inclination angle of the inclined surface.

  In the present invention, the inclination angle of the optical axis is preferably half of the inclination angle of the inclined surface. According to this, it is possible to achieve both suppression of light leakage from the inclined surface and improvement in luminance uniformity on the light exit surface.

  In this invention, it is preferable that the said end surface inclines to the side orthogonal to the optical axis of the said light source with respect to the surface orthogonal to the said light-projection surface. According to this, since the end surface of the light guide plate is inclined to the side orthogonal to the optical axis, it is possible to increase the light capturing efficiency with respect to the light guide plate at the end surface. In particular, it is desirable that the end surface of the light guide plate is orthogonal to the optical axis of the light source.

  In this invention, it is preferable to have the supporting member which supports the said light source and inclines on the opposite side of the said light-projection surface. According to this, the inclination of the optical axis can be set by supporting the light source on the inclined support member.

  In this invention, it has a supporting member which supports the said light source, and it is preferable that the said light source has the installation surface supported by the said supporting member, and the said optical axis inclined with respect to this installation surface. According to this, since the light source has the optical axis inclined with respect to the installation surface, the inclination of the optical axis can be set.

  In the present invention, it is preferable that the light emitting surface is in close contact with the end surface. Since the light emission surface of the light source is in close contact with the end surface of the light guide plate, it is possible to increase the efficiency of taking light into the light guide plate.

  Next, an electro-optical device according to the present invention includes any one of the illumination devices described above, and an electro-optical control body that is disposed on the light emission surface of the illumination device. Here, the electro-optical control body refers to an electro-optical material that can control the electro-optical material in some form, such as a liquid crystal display body or an electrophoretic display body without an illuminating device or an illumination function portion.

  In the present invention, it is preferable that the electro-optic control body is disposed in parallel with the light emitting surface. According to this, since the electro-optic control body and the light emitting surface of the light guide plate are arranged in parallel, the overlapping portion between the electro-optic control body and the light guide plate can be most efficiently thinned.

  Furthermore, an electronic apparatus according to the present invention includes the above-described electro-optical device. The electronic apparatus according to the present invention is preferably a portable electronic apparatus in that the electro-optical device can be effectively used to be thin and small.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1A is a schematic longitudinal sectional view showing the structure of the electro-optical device 100 of this embodiment, and FIG. 1B is a schematic plan view of an illumination unit 110 that is an illumination device provided in the electro-optical device 100. is there.

  The electro-optical device 100 according to the present embodiment includes the illumination unit 110 described above and an electro-optical control body 120 that is disposed so as to overlap the illumination unit 110. The illumination unit 110 includes a light source 111 composed of LEDs and the like, and a light guide plate 112 disposed adjacent to the light source 111. In addition, the lighting unit 110 includes a reflector 113 disposed behind the light guide plate 112 and a light guide plate, if necessary, in order to improve the light use efficiency and the luminance uniformity on the light exit surface. A light diffusing plate 114 and light collecting plates 115 and 116 disposed in front of 112 are provided.

  The light source 111 is mounted on the wiring board 117, and is configured such that electric power is supplied to the light source 111 from the outside via the terminal portion 117x and the like. In the present embodiment, the light source 111 is a light emitting element having a rectangular parallelepiped (chip) shape, and one outer surface thereof (a surface facing the light guide plate 112) is a light emitting surface 111a. Examples of the light emitting element include LED (light emitting diode) and LD (laser diode). As such an element, for example, a semiconductor bonding structure such as an LED is covered with a transparent resin, the transparent resin is exposed only on the light emitting surface 111a, and the other surface is made of a light reflective material such as a white resin. What is composed is known. The wiring board 117 is preferably an FPC (flexible wiring board) made of polyimide resin or the like, but may be a hard board (rigid wiring board) made of glass epoxy resin, phenol resin, ceramics, or the like.

  The light guide plate 112 is a flat rectangular plate and is made of a transparent material such as acrylic resin or polycarbonate. Since the material preferably has a light refractive index as high as possible, it is desirable to use, for example, polycarbonate having a refractive index of about 1.56 to 1.57. The light guide plate 112 is provided with an end surface 111a opposite to the light source 111. The light emitted from the light source 111 is taken in from the end surface 111a, and gradually propagates from the light emitting surface 112b which is the upper surface while propagating the light inside. Released. On the surface (back surface) 112c opposite to the light emitting surface 112b, light deflecting means described later is provided. By this light deflecting means, the light propagating in the light guide plate 112 is gradually deflected to the light emitting surface 112b side and emitted. It has come to be.

  In the illustrated example, the light guide plate 112 has a light emitting surface 112b and a back surface 112c configured in parallel, and a planar area where the light emitting surface 112b is formed is a flat region B having a parallel plate shape.

  Further, the light emitted from the back surface 112c is reflected by the reflecting plate 113 disposed on the back surface 112c, returns to the light guide plate 112 again, and is emitted from the light emitting surface 112b. As the reflecting plate 113, a white resin sheet such as a polyethylene resin, or a metal sheet deposited on the surface of a base sheet is used.

  A side of the light guide plate 112 where the end surface 111a is provided is provided with an overhanging portion 112e that protrudes outward from the end surface 111a. And the end surface 111a is provided in the recessed part recessed in planar view in the said edge | side. An inclined edge surface 112d, which is a part of the upper surface of the light guide plate 112, is formed between the end surface 111a and the light emitting surface 112b. Unlike the flat light emitting surface 112b, the inclined edge surface 112d is inclined so as to gradually move upward toward the end surface 111a, whereby the plane range where the inclined edge surface 112d is provided is the end surface. The light incident region C has a thickness that gradually increases toward 111a.

  By providing the light incident region C, when the thickness of the light emission surface 111a of the light source 111 is larger than the thickness of the flat region B, the range in the thickness direction of the end surface 112a is expanded. A larger amount of emitted light can be taken into the light guide plate 112. At this time, in order to increase the efficiency of capturing light into the light guide plate 112, the thickness of the end surface 112a is preferably equal to or greater than the thickness of the light emitting surface 111a. In the illustrated example, the thickness of the end surface 112a is the same as the thickness of the light emitting surface 111a. Actually, if the thickness of the end surface 112a is excessively increased, the inclination angle θ2 is increased or the planar size of the light guide plate 112 is increased. Therefore, the thickness of the end surface 112a is 100% to the thickness of the light emitting surface 111a. It is desirable to set within the range of 120%.

  On the surface of the protruding portion 112e of the light guide plate 112, the surface of the wiring substrate 117 on which the light source 111 is mounted is supported. The wiring board 117 and the overhanging portion 112e may be held in a state where they are simply in contact with each other, or may be fixed with an adhesive, a double-sided adhesive sheet, or the like. The surface of the overhanging portion 112e is inclined at the same inclination angle as the inclined edge surface 112d or a different inclination angle, and the inclination angle of the surface of the overhanging portion 112e is the inclination angle of the wiring board 117 (in the illustrated example, the light source 111 (the inclination angle of the optical axis 111). In the present embodiment, the inclination angle of the optical axis of the light source 111 described later is set by the inclination angle of the wiring board 117 corresponding to the support member on which the light source 111 is supported.

  The electro-optic control body 120 has a structure in which a pair of substrates 121 and 122 made of glass, plastic, or the like are bonded together by a sealing material 123 and a liquid crystal 124 that is an electro-optic material is sealed between the substrates 121 and 122. Have. Polarizing plates 125 and 126 are disposed (attached) on the outer surfaces of the substrates 121 and 122.

  The electro-optic control body 120 can apply an electric field to the electro-optic material by an electrode structure (not shown) formed on the inner surfaces of the substrates 121 and 122, and can control the optical state of the electro-optic material by the electric field. It is configured to be able to. In the case of the illustrated example, a desired display mode is realized according to the light modulation characteristics of the liquid crystal 124 controlled according to the applied electric field.

  The display area A shown in FIG. 1 is an area in which the electro-optic substance (liquid crystal) is controlled in the electro-optic control body 120 and the display mode is controllable, for example, typically Is a region in which a desired display can be realized by arranging a plurality of pixels vertically and horizontally and making these pixels independently controllable.

  2 is an enlarged partial cross-sectional view showing the vicinity of the light source 111 in the illumination unit 110 of the present embodiment, and FIG. 3 is an enlarged view showing the vicinity of the light source 11 in the illumination unit 10 of the comparative example shown in FIG. It is a fragmentary sectional view. In the illustrated example, a plurality of light deflection inclined surfaces 12cx and 112cx formed on the rear surfaces 12c and 112c of the light guide plates 12 and 112 are provided as an example of the light deflecting unit. However, these light deflection slopes are merely examples of light deflection means, and are not limited in the present invention.

  As shown in FIG. 2, in the present embodiment, the optical axis 111 x of the light source 111 is set to be inclined to the opposite side of the light emitting surface 112 b of the light guide plate 112. That is, in the comparative example shown in FIG. 8, as shown in FIG. 3, the optical axis 11x is set parallel to the light exit surface 12b. However, in this embodiment, the optical axis 111x is parallel to the light exit surface 112b. Is set so as to extend in a direction inclined toward the back surface 112c.

  In the comparative example shown in FIG. 3, since the optical axis 11x is set parallel to the light emitting surface 12b, the light emitted from the light source 11 has a lot of light having a small incident angle with respect to the inclined edge surface 12d. Therefore, light is likely to be emitted from the inclined edge surface 12d to the outside, and light leakage is increased. However, in the present embodiment, the optical axis 111x is inclined with respect to the light emitting surface 112b and inclined toward the back surface 112c. As a result, the incident angle of the light emitted from the light source 111 with respect to the inclined edge surface 112d is increased, so that the light is easily totally reflected by the inclined edge surface 112d, and light leakage from the inclined edge surface 112d can be reduced. Therefore, it is possible to suppress a decrease in the efficiency of taking light into the light guide plate 112, and it is possible to prevent a region with a large luminance (eyeball region) from being generated in the light source 111 side region of the light guide plate 112.

  In the present embodiment, it is preferable that the inclination angle θ1 of the optical axis 111x with respect to the light emission surface 112b is set to be equal to or less than the inclination angle θ2 of the inclined edge surface 112d with reference to the light emission surface 112b. This is because if the angle θ1 is larger than θ2, the light capturing angle with respect to the light guide plate 112 is excessively biased toward the back surface 112c, and the light capturing efficiency is lowered, or the light reflected by the back surface 112c and the reflecting plate 113 is reduced. This is because the luminance in the vicinity of the light source 111 may be excessive, which may adversely affect the uniformity of the luminance distribution of the light emitted from the light emitting surface 112b. In particular, from the same viewpoint, it is more desirable that the inclination angle θ1 is less than the inclination angle θ2.

  The inclination angle θ2 (or the average value) of the inclined edge surface 112d in the light incident area C is 1 to 10 degrees with respect to the light emitting surface 112b when the light guide plate 112 having a light refractive index of about 1.5 is used. , Preferably in the range of 2 to 8 degrees. However, the preferable value of the inclination angle θ2 varies depending on the light refractive index of the light guide plate 112, the inclination angle of the optical axis 111x of the light source 111, and the like.

  In the illustrated example, the inclination angle θ1 is set to half of the inclination angle θ2. In this case, the angle difference between the optical axis 111x and the inclined edge surface 112d and the angle difference between the optical axis 111x and the back surface 112c become the same, so the vicinity of the end surface 112a in the light guide plate 112 with respect to the light emitted from the light source 111 The front and back sides are evenly positioned. Therefore, since the suppression of light leakage from the inclined edge surface 112d and the influence of the reflected light from the back surface 112c and the reflecting plate 113 can be balanced, it is possible to increase the efficiency of taking in substantial light into the light guide plate 112. Since the uniformity of the luminance of the light emitting surface 112b on the light source 111 side of the light guide plate 112 can be improved, it is possible to realize the optical characteristics with a high level and in a good balance. Specifically, θ1 is preferably about 0.4 to 0.6 times θ2, and preferably within a range of 0.45 to 0.55 times.

  In the comparative example shown in FIG. 3, when the light emission surface 11 a of the light source 11 has a thickness of 0.6 mm and the light capturing efficiency is 100% when the light guide plate is a parallel plate having a thickness of 0.6 mm. When the inclination angle of the inclined edge surface 12d is 6 degrees and the thickness of the flat region B of the light guide plate 112 is 0.45 mm, the capturing efficiency is about 85%. Further, when the inclination angle of the inclined edge surface 12d was 6 degrees and the thickness of the flat region B of the light guide plate 112 was 0.3 mm, the capturing efficiency was about 70%. The capture efficiency of these comparative examples is higher than when the parallel plate-shaped light guide plate is used as it is, but as the difference between the thickness of the light emitting surface 11a and the thickness of the flat region B increases, Relatively decreases. Further, when the difference between the thickness of the light emitting surface 11a and the thickness of the flat region B is increased, the inclination angle of the inclined edge surface 12d is increased or the width of the inclined edge surface 12d (in the horizontal direction of FIG. 3). It is necessary to increase the measured width. Here, when the inclination angle is increased, light leakage from the inclined edge surface 12d is further increased, and the capture efficiency is lowered. On the other hand, when the width of the inclined edge surface is increased, the size of the area (frame area) around the display area A of the light guide plate 12 is increased, which is contrary to the downsizing of the apparatus.

  In the present embodiment, the light leakage from the inclined edge surface 112d can be reduced by tilting the optical axis 111x of the light source 111 to the opposite side (back surface 112c side) of the light emitting surface 112b, and light to the light guide plate 112 can be reduced. Can be increased, and the influence on the uniformity of luminance on the light exit surface 112b of the light guide plate 112 can be suppressed. Under the same conditions as in the above comparative example, the light capturing efficiency can be increased by inclining the optical axis 111x by 3 degrees toward the back surface 112c, and the luminance uniformity on the light emitting surface 112b is almost affected. In addition, in the region near the end face 112a, the uniformity of luminance can be improved over the comparative example.

  In this embodiment, since the above effects can be obtained, the inclination angle θ2 of the inclined edge surface 112d is set larger than that of the comparative example in a range that does not affect the brightness and luminance uniformity of the light guide plate 112. Therefore, the thickness of the flat region B can be made thinner than that in the comparative example, and the thickness of the entire apparatus can be reduced. In addition, since the width of the inclined edge surface 112d can be reduced instead of increasing the inclination angle θ2, it is possible to reduce the area protruding outward from the display area A and reduce the planar size of the device. become.

  Furthermore, in this embodiment, the end surface 112a of the light guide plate 112 is inclined to the surface side orthogonal to the optical axis 111x with respect to the surface orthogonal to the light emitting surface 112b. Thereby, it is possible to further increase the efficiency of capturing light incident from the end face 112a. In particular, it is most desirable to form the end surface 112a in parallel with a surface orthogonal to the optical axis 111x.

  FIG. 4 is an enlarged partial sectional view showing an embodiment different from the above embodiment. Since this embodiment basically has the same configuration of each part as the above-described embodiment, the same parts are denoted by the same reference numerals, and the description thereof is omitted.

  In the present embodiment, the light emission surface 111a of the light source 111 and the end surface 112a of the light guide plate 112 have an inclination angle that is perfectly aligned (that is, the light emission surface 111a and the end surface 112a are both flat, and the end surface 112a is 2 is different from the previous embodiment shown in FIG. 2 in that it is in close contact with each other. By bringing the light emitting surface 111a and the end surface 112a into close contact with each other, the amount of light leaking to the outside can be reduced, so that light loss due to reflection on both surfaces is reduced, and the efficiency of taking light into the light guide plate 112 can be further increased. .

  FIG. 5 is an enlarged partial sectional view showing an embodiment further different from the above embodiment. Also in this embodiment, since it has the structure of each part similar to embodiment described previously, the same code | symbol is attached | subjected to the same part and those description is abbreviate | omitted.

  In the present embodiment, the light source 111 ′ is different from the embodiments described above. In the previous embodiment, the light source 111 is supported by the support surface that is inclined with respect to the light emitting surface 112b, that is, the surface of the wiring board 117 that is a support member, and thus the optical axis 111x is inclined. In this embodiment, the light source 111 ′ has an installation surface 111b inclined with respect to the optical axis 111x, and the installation surface 111b is supported by the surface of the wiring board 117 serving as a support surface. The axis 111x is inclined. For example, in the illustrated example, a wedge-shaped additional portion 111s is provided on the outer surface of the main body 111t, and the surface of the additional portion 111s constitutes the installation surface 111b.

  As described above, for example, even when the wiring board 117 is installed horizontally as shown in the drawing (that is, the support surface which is the surface thereof is parallel to the light emitting surface 112b of the light guide plate 112, for example) The optical axis 111x of the light source 111 ′ mounted on the substrate 117 is inclined toward the back surface 112c side of the light guide plate 112. Accordingly, since the inclination angle of the optical axis 111x can be set by the structure of the light source 111 ′ itself, the structure for supporting the wiring board 117 (for example, the structure of the projecting portion of the light guide plate 112, or a case body not shown) Almost no other structural changes are required.

  Next, a configuration example of an electronic apparatus on which the electro-optical device 100 of each of the above embodiments is mounted will be described with reference to FIGS.

  FIG. 6 shows a notebook personal computer which is an embodiment of the electronic apparatus according to the present invention. The personal computer 200 includes a main body unit 201 including a plurality of operation buttons 201a and other operation devices 201b, and a display unit 202 connected to the main body unit 201 and including a display screen 202a. In the case of the illustrated example, the main body unit 201 and the display unit 202 are configured to be openable and closable. The above-described electro-optical device (liquid crystal display device) 100 is built in the display unit 202, and a desired display image is displayed on the display screen 202a. In this case, a display control circuit for controlling the electro-optical device 100 is provided inside the personal computer 200. The display control circuit is configured to send an image signal and other input data and a predetermined control signal to the electro-optical device 100 to determine the operation mode.

  In this example, by using the electro-optical device 100 of the embodiment, it is possible to reduce the thickness of the display unit 202 and to reduce the width of the frame portion (the peripheral portion around the display screen 202a). The computer 200 can be reduced in thickness and size.

  FIG. 7 shows a mobile phone which is another embodiment of the electronic apparatus according to the present invention. A cellular phone 300 shown here includes an operation unit 301 including a plurality of operation buttons 301a and 301b and a mouthpiece, and a display unit 302 including a display screen 302a and a mouthpiece. The electro-optical device 100 is incorporated inside. The display image formed by the electro-optical device 100 can be viewed on the display screen 302a of the display unit 302. In this case, a display control circuit that controls the electro-optical device 100 is provided inside the mobile phone 300. The display control circuit is configured to send an image signal and other input data and a predetermined control signal to the electro-optical device 100 to determine the operation mode.

  Also in this embodiment, since the display portion 302 can be made thinner and narrower, the mobile phone can be made thinner and smaller.

  It should be noted that the electro-optical device and the electronic apparatus of the present invention are not limited to the illustrated examples described above, and various modifications can be made without departing from the scope of the present invention. For example, the illuminating device of the present invention is not limited to a liquid crystal display device, and can be used for various electro-optical devices, and can also be applied to various products other than electro-optical devices, such as lighting fixtures and inspection devices. It is.

  In addition, the light guide plate according to the present invention is not limited to a light emitting surface provided in a parallel plate-like portion as in each of the above embodiments, and a light incident area on the end surface side of the light emitting surface. It may be a wedge-shaped light guide plate whose thickness gradually increases toward.

FIG. 2 is a schematic longitudinal sectional view (a) showing an overall configuration of an embodiment of an electro-optical device and a schematic plan view of an illumination unit. The expanded partial sectional view of the lighting unit of an embodiment. The expanded partial sectional view of the lighting unit of a comparative example. The expanded partial sectional view of the lighting unit of different embodiment. Furthermore, the expanded partial sectional view of the illumination unit of different embodiment. The schematic perspective view of embodiment of an electronic device. The schematic perspective view of embodiment of another electronic device. FIG. 2 is a schematic longitudinal sectional view (a) showing an overall configuration of an electro-optical device of a comparative example and a schematic plan view (b) of an illumination unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Electro-optical device, 110 ... Illumination unit, 111 ... Light source, 111x ... Optical axis, 111a ... Light emission surface, 112 ... Light guide plate, 112a ... End surface, 112b ... Light-emitting surface, 112c ... Back surface, 112d ... Inclined edge surface 112e ... overhanging part, 120 ... electro-optic control body, 200, 300 ... electronic equipment

Claims (12)

A light guide plate having a planar light emitting surface; and a light source having a light emission surface disposed opposite to an end surface of the light guide plate, and light emitted from the light source passes through the end surface into the light guide plate. In the illumination device configured to be incident on the light guide plate and propagated through the light guide plate and emitted from the light exit surface,
The light guide plate is provided with a region configured to increase in thickness toward the end surface in at least a partial range in a direction toward the end surface,
An illuminating device characterized in that an optical axis of the light source is tilted toward a surface opposite to the light emitting surface.   The lighting device according to claim 1, wherein the light guide plate has a light incident region whose thickness gradually increases toward the end surface on the end surface side of the light emitting surface.   An inclined surface for gradually increasing the thickness of the light incident region toward the end surface is formed, and the inclined surface is provided adjacent to the end surface side of the light emitting surface. Item 3. The lighting device according to Item 2.   The lighting device according to claim 3, wherein an inclination angle of the optical axis with respect to the light exit surface is equal to or less than an inclination angle of the inclined surface.   The lighting device according to claim 4, wherein an inclination angle of the optical axis is half of an inclination angle of the inclined surface.   The lighting device according to any one of claims 1 to 5, wherein the end surface is inclined to a side orthogonal to the optical axis of the light source with respect to a surface orthogonal to the light emitting surface.   The lighting device according to claim 1, further comprising a support member that supports the light source and is inclined to the opposite side of the light emitting surface.   7. A support member for supporting the light source, wherein the light source has an installation surface supported by the support member and the optical axis inclined with respect to the installation surface. The lighting device according to any one of the above.   The lighting device according to claim 1, wherein the light emission surface is in close contact with the end surface.   An electro-optical device comprising: the illuminating device according to claim 1; and an electro-optical control body that is disposed on the light emission surface of the illuminating device.   The electro-optical device according to claim 10, wherein the electro-optical control body is disposed in parallel with the light emitting surface. An electronic apparatus comprising the electro-optical device according to claim 10.

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