JP2013171631A - Light source device and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device and an electronic equipment capable of downsizing a light source.SOLUTION: A light source device includes a light source emitting light of a first wavelength, a light guide plate having a light-incident face letting in light of the first wavelength from the light source as well as a light emission face emitting light of the first wavelength incident from the light-incident face, and a wavelength conversion part for converting part of light of the first wavelength emitted from the light emission face into light of a second wavelength.

Description

  The present invention relates to a light source device and an electronic apparatus.

  In mobile type electronic devices such as mobile phones, PDAs, notebook personal computers, portable game machines, and portable music players, liquid crystal display devices that display various information and images are widely used. The display area is illuminated using a backlight (light source device). In this backlight, light from a light source is incident from a side surface of a light guide plate, and planar light is emitted from a light emission surface (for example, an upper surface) of the light guide plate to widely illuminate a liquid crystal display panel (for example, Patent Document 1). reference).

  In a mobile type electronic device such as a mobile phone, it is necessary to enlarge an area for displaying various information and images without increasing the size of the device itself. Therefore, the display area is enlarged by narrowing a so-called frame portion around the display area. In addition, the frame portion is required to be narrowed in order to improve the design of electronic devices.

JP 2011-44324 A

  However, in the form of the narrow frame as described above, the light source is arranged in the frame portion. Therefore, in order to narrow the frame, the light source is required to be as small as possible.

  In view of the circumstances as described above, it is an object of the present invention to provide a light source device and an electronic apparatus capable of downsizing a light source.

  According to the first aspect of the present invention, the light source has a light source that emits light having a first wavelength and a light incident surface that makes light having the first wavelength incident from the light source, and the first wavelength incident from the light incident surface. There is provided a light source device including a light guide plate having a light emission surface that emits the light and a wavelength conversion unit that converts light having a first wavelength emitted from the light emission surface into light having a second wavelength.

  According to the second aspect of the present invention, an electronic apparatus having a display unit that performs display using light from the light source device in the display unit, the light source device according to the first aspect of the present invention as the light source device. Used electronic devices are provided.

  ADVANTAGE OF THE INVENTION According to the aspect of this invention, the light source device and electronic device which can reduce a light source in size can be provided.

The figure which shows the structure of the light source device which concerns on 1st embodiment of this invention. The figure which shows the structure of a part of light source device which concerns on this embodiment. Sectional drawing which shows the structure of the electronic device which concerns on 2nd embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
In each drawing used for the following description, the scale is appropriately changed in order to make each member and each part recognizable.

[First embodiment]
First, a first embodiment of the present invention will be described.
FIG. 1 is a perspective view illustrating a light source device 100 according to this embodiment. FIG. 2 is a cross-sectional view illustrating a partial configuration of the light source device 100. As shown in FIGS. 1 and 2, the light source device 100 includes a light source 2, a light guide plate 1, and a wavelength conversion unit 3.

  The light source 2 has a plurality of light emitting devices (light emitting device 21, light emitting device 22, light emitting device 23, and light emitting device 24). The light-emitting device 21, the light-emitting device 22, the light-emitting device 23, and the light-emitting device 24 are arranged at substantially equal intervals in one direction.

  As shown in FIG. 2, the light-emitting device 21 includes a light-emitting body 21a and a package 21b that houses the light-emitting body 21a. Similarly, the light emitting device 22 includes a light emitter 22a and a package 22b that accommodates the light emitter 22a. The light-emitting device 23 includes a light-emitting body 23a and a package 23b that houses the light-emitting body 23a. The light emitting device 24 includes a light emitter 24a and a package 24b that accommodates the light emitter 24a.

  As the light emitters 21a to 24a, for example, blue LEDs are used. However, the light source 2 is not limited to the LED, and various light emitters such as a cold cathode tube may be used. Moreover, it is not limited to the number of light-emitting bodies 21-24 as shown in FIG.

  Openings 21c to 24c directed to the light incident surface 11c of the plate-like body 11 are formed in the packages 21b to 24b, respectively. Light emitted from the light emitters 21a to 24a is emitted from the openings 21c to 24c toward the light incident surface 11c. The light emitted from the openings 21c to 24c is blue light.

  The packages 21b to 24b are provided with only the light emitters 21a to 24a that emit blue light. For example, a yellow phosphor layer (converts blue light into white light as included in a conventional light emitting device package). The wavelength conversion layer) is not provided. For this reason, the packages 21b to 24b have a reduced size because the phosphor layer is not provided.

  In the present embodiment, the light emitting surfaces 21e to 24e of the light emitters 21a to 24a are arranged so as to coincide with the open end surfaces 21d to 24d of the packages 21b to 24b. In this configuration, since light is emitted from the opening end faces 21d to 24d, the dimensions of the packages 21b to 24b can be reduced accordingly. For this reason, size reduction of the light source 2 can be achieved.

  The arrangement shown in FIG. 2 is merely an example, and other arrangements may be used. For example, the light emitting surfaces 21e to 24e may be arranged in a state of protruding to the light guide plate 1 side with respect to the opening end surfaces 21d to 24d.

  The light guide plate 1 is an optical member that emits light from the light source 2 in a planar shape. The light guide plate 1 has a plate-like body 11. The plate-like body 11 is formed in a rectangular shape in plan view with a material that sufficiently transmits light in the visible light region, such as acrylic resin, polycarbonate, and various other types of glass. The thickness of the plate-like body 11 is, for example, 30 μm to 500 μm.

  The plate-like body 11 is arranged so that one side surface 11 c is parallel to the arrangement direction of the light emitting devices 21 to 24 of the light source 2. For this reason, the said side surface 11c of the plate-shaped object 11 and the opening parts 21c-24c of each light-emitting devices 21-24 are the opposingly arranged state. In the light source 2, the blue light emitted from the openings 21 c to 24 c is incident from the side surface 11 c of the plate-like body 11. Therefore, the side surface 11 c is a light incident surface of light from the light source 2. Hereinafter, the side surface 11c may be referred to as a light incident surface 11c.

  The surface side (upper surface side in FIG. 1) of the plate-like body 11 is a light emitting surface 11a that emits planar light, and is formed on a smooth surface. The light exit surface 11a may be surface-treated in order to diffuse light, and although not shown, an optical sheet in which a diffusion sheet or a minute prism is formed may be attached to the entire light exit surface 11a. . Such a surface treatment or sticking of the diffusion sheet is not only for adjusting the direction and spread of the light emitted from the light emitting surface 11a, but also when the plate-like body 11 is viewed from the light emitting surface 11a side. It is used for the purpose of hiding the shape of the structure part 12 (the structure part 12 will be described later).

  On the back surface 11b of the plate-like body 11, a saw-like structure portion 12 having a plurality of reflecting surfaces is formed. This structure part 12 guides the light introduced from the light incident surface 11c (side surface) of the plate-like body 11 to the light emitting surface 11a side, and the planar light emitted from the light emitting surface 11a becomes uniform. In this manner, the angle and size of each reflecting surface are changed as the distance from the light incident surface 11c increases.

  However, the structure part 12 is not limited to the structure shown in FIG. For example, in addition to the structure 12 that reflects the light, the light may be guided to the light exit surface 11a by scattering or diffraction. Further, instead of the saw-like structure portion 12, convex or concave dots may be formed on the back surface 11b. In the structure using dots, as the distance from the light incident surface 11c increases, the area of the dots is increased so that the planar light emitted from the light emitting surface 11a becomes uniform.

  The wavelength conversion unit 3 includes a phosphor sheet 31 and converts the wavelength of part of the first wavelength light emitted from the light source 2. The phosphor sheet 31 has a configuration in which a phosphor 33 is included in a sheet member 32 formed using a material having high light transmittance. As a material of the sheet member 32, for example, a transparent resin such as acrylic resin or polycarbonate, various glasses, or the like is used. Further, as the phosphor 33, for example, a phosphor material that is excited by irradiation with light having a first wavelength and generates light having a second wavelength different from the first wavelength can be used. Uses a phosphor material that is excited by irradiation with blue light to generate yellow light. And it is comprised so that white light can be obtained by the color mixture of yellow light and the blue light which was not wavelength-converted by the wavelength conversion part 3. FIG. Note that the phosphor 33 is not limited to one type, and a plurality of types of phosphor materials may be used in combination. For example, a phosphor material that generates red light when irradiated with blue light, and green light when irradiated with blue light. In this case, white light can be obtained by mixing red light and green light generated from the phosphor and blue light that has not been wavelength-converted by the wavelength conversion unit 3. it can. Thus, the phosphor sheet 31 is formed so as to be able to transmit light, and is formed so as to convert the wavelength of light transmitted through the phosphor sheet 31.

  The phosphor sheet 31 is formed in a rectangular shape in plan view, and has a size that covers the light emission surface 11 a of the plate-like body 11. The phosphor sheet 31 has a first surface 31a on which light emitted from the light emission surface 11a is incident, and a second surface 31b on which light incident on the first surface 31a is emitted. The first surface 31a is disposed to face the light emitting surface 11a of the plate-like body 11, and is provided in parallel to the light emitting surface 11a.

  The phosphor sheet 31 has a function of diffusing and emitting light emitted from the light emitting surface 11a over the entire second surface 31b. For this reason, since the light from the plurality of light source devices 21 to 24 is diffused in the light guide plate 1 and the phosphor sheet 31, the occurrence of luminance unevenness is suppressed.

  Note that the second surface 31b of the phosphor sheet 31 may have a configuration in which surface treatment is performed in order to adjust the direction and spread of light emitted from the second surface 31b. Examples of such a configuration include a configuration in which a diffusion sheet is disposed on the entire second surface 31b, a configuration in which a micro prism is formed on the second surface 31b, and a configuration in which an optical sheet is attached to the second surface 31b. It is done. When such surface treatment is performed, the occurrence of uneven brightness is further suppressed.

  In addition to forming a space between the light source 2 and the light guide plate 1 as shown in FIGS. 1 and 2, a transparent resin or the like may be filled between them. By filling a transparent resin or the like between the light guide plate 1 and the light source 2, the transparent resin or the like functions as an adhesive, and the two are integrated. You may match | combine the refractive index of this transparent resin and the plate-shaped body 11 of the light-guide plate 1. FIG. In the light source device 100 shown in FIG. 1, one side surface of the light guide plate 1 is used as the light incident surface 11c. However, the present invention is not limited to this, and two or more side surfaces of the plate-like body 11 are used as light incident surfaces. 2 may be arranged.

  In the above configuration, the blue light generated in the light emitters 21a to 24a of the light source 2 is emitted as it is from the openings 21c to 24c. The blue light emitted from the openings 21c to 24c travels in the direction (first direction) toward the light incident surface 11c of the plate 11 and enters the light incident surface 11c.

  The blue light incident on the light incident surface 11c is reflected by the structure portion 12 of the plate-like body 11, diffused over the entire plate-like body 11, and emitted as planar light from the light emission surface 11a. . The blue light emitted in a planar shape from the light emitting surface 11a travels in the direction (second direction) toward the first surface 31a of the phosphor sheet 31 as it is and enters the first surface 31a of the phosphor sheet 31. To do. The second direction, which is the traveling direction of the blue light emitted from the light emitting surface 11a, is perpendicular to the first direction, which is the traveling direction of the blue light emitted from the openings 21c to 24c. Become.

  Part of the blue light incident on the phosphor sheet 31 from the first surface 31 a is irradiated to the phosphor 33 included in the sheet member 32 in the process of passing through the phosphor sheet 31 to excite the phosphor 33. By this action, yellow light is generated from the phosphor 33. White light is formed by a mixture of yellow light generated by wavelength conversion in the phosphor sheet 31 and blue light not subjected to wavelength conversion, and is emitted as planar light from the second surface 31 b of the phosphor sheet 31.

  As described above, in the present embodiment, the white light is not formed in the light source 2, but the wavelength conversion unit is added to the optical path of the blue light emitted in the second direction orthogonal to the first direction by the action of the light guide plate 1. 3 is disposed and white light is formed by the wavelength conversion unit 3, the size of the light source 2 in the first direction can be reduced.

  As described above, the light source device 100 according to the present embodiment includes the light source 2 that emits blue light and the light incident surface 11c that receives the light from the light source 2, and the light incident from the light incident surface 11c. A light guide plate 1 having a light emission surface 11a to be emitted, and a wavelength conversion unit 3 for converting a part of blue light emitted from the light emission surface 11a into yellow light, and wavelength conversion by the yellow light and the wavelength conversion unit 3 Since the white light can be obtained by the color mixture with the blue light that has not been performed, the white light can be emitted without the light source 2 converting the wavelength of the blue light. Thus, since it is not necessary to provide the wavelength conversion part in the light source 2, the light source 2 can be reduced in size.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.
FIG. 3 is a cross-sectional view illustrating the configuration of the electronic device 5 according to the present embodiment. In the present embodiment, a portable liquid crystal display device will be described as an example of the electronic device 5. The electronic device 5 includes a housing 51, a liquid crystal panel 52, and a light source device 53. The housing 51 includes an opening 51b having a width L surrounded by a frame portion 51a having a width W, and houses the liquid crystal panel 52 and the light source device 53 therein.

  The liquid crystal panel 52 is roughly composed of a front glass substrate 52a provided with individual electrodes, a back glass substrate 52b provided with a common electrode, and a liquid crystal layer 52c sandwiched therebetween. Further, the liquid crystal panel 52 is held by the housing 51 in a state where the periphery thereof is sandwiched between the frame portion 51a and the rib 51c. Thereby, the area of the width L of the opening 51 a is used as the display area of the liquid crystal panel 52.

  The liquid crystal panel 52 includes a polarizing film (not shown) arranged with glass substrates 52a and 52b interposed therebetween, a driver for driving liquid crystal (not shown), and the like. As the liquid crystal panel 52, various known liquid crystal panels other than those shown in the figure are used.

  The light source device 53 is disposed on the glass substrate 52 b side of the liquid crystal panel 52 in the housing 51 with the light emission surface 11 a of the light guide plate 1 facing the liquid crystal panel 52. The light source device 53 has the same configuration as the light source device 100 described in the first embodiment.

  As shown in FIG. 3, the light source 2 is arranged in a range of a width W on the back side of the frame portion 51b. The light guide plate 1 is disposed in a state where the end portion is inserted into the back side of the frame portion 51b so that a part of the light guide plate 1 is located on the boundary Y between the width L and the width W. Thereby, the light reduction part 41 on the light emission surface 11a will be in the state arrange | positioned in the position which cross | intersected the boundary Y. FIG.

  Further, the phosphor sheet 31 constituting the wavelength conversion unit 3 is attached to the glass substrate 52b of the liquid crystal panel 52 through, for example, an adhesive (not shown). In this case, the adhesive used for attaching the phosphor sheet 31 is formed using a light transmissive material. In addition, the same material as the fluorescent substance 33 contained in the fluorescent substance sheet 31 may be contained in the adhesive. In the present embodiment, the phosphor sheet 31 is affixed to the glass substrate 52b of the liquid crystal panel 52. However, the present invention is not limited to this, and the phosphor sheet 31 is separated from the glass substrate 52b. It does not matter.

  Moreover, in this embodiment, although it is the structure by which the clearance gap was formed between the fluorescent substance sheet 31 and the light-guide plate 1, it is not restricted to this, The fluorescent substance sheet 31 and the light-guide plate 1 are arrange | positioned without a clearance gap. The structure to be made may be sufficient, and the structure which arrange | positions the insertion member which can permeate | transmit light between the fluorescent substance sheet 31 and the light-guide plate 1 may be sufficient. In this case, the interposer may include the phosphor.

  In the electronic device 5 described above, when the light source 2 is turned on, the blue light introduced into the light guide plate 1 from the light incident surface 11c is guided to the light emitting surface 11a by the structure portion 12 on the back surface, and from the light emitting surface 11a. It is emitted as planar light. This blue light enters the phosphor sheet 31 as it is, and in the process of passing through the phosphor sheet 31, a part of the blue light excites the phosphor 33 to generate yellow light. White light is formed by mixing yellow light generated by wavelength conversion in the phosphor sheet 31 and blue light not wavelength-converted by the phosphor sheet 31, and planar light is emitted from the second surface 31b of the phosphor sheet 31. The liquid crystal panel 52 is illuminated from the back side.

  Thus, even if the light source 2 does not convert the wavelength of blue light, the liquid crystal panel 52 can be irradiated with white light. Therefore, it is not necessary to provide a wavelength conversion unit in the light source 2, and the light source 2 can be reduced in size. By reducing the size of the light source 2, the width W of the frame portion 51 a of the electronic device 5 can be reduced.

DESCRIPTION OF SYMBOLS 100 ... Light source device 1 ... Light guide plate 2 ... Light source 3 ... Wavelength conversion part 5 ... Electronic device 11 ... Plate-shaped body 11a ... Light emission surface 11c ... Light incident surface 31 ... Phosphor sheet 32 ... Sheet member (light transmission member) 33 ... phosphor

Claims (9)

A light source that emits light of a first wavelength;
A light guide plate having a light incident surface on which light of the first wavelength from the light source is incident and having a light emission surface that emits light of the first wavelength incident from the light incident surface;
A light source device comprising: a wavelength conversion unit that converts part of the light having the first wavelength emitted from the light emission surface into light having the second wavelength. The light source device according to claim 1, wherein the wavelength conversion unit is capable of transmitting the light having the first wavelength and the light having the second wavelength, and is disposed so as to cover the light emission surface. The light source device according to claim 1, wherein the wavelength conversion unit is formed in a sheet shape. The light source device according to any one of claims 1 to 3, wherein the wavelength conversion unit is detachably provided on the light exit surface. The light of the first wavelength until it enters the light incident surface from the light source travels in the first direction,
The light emitted from the light exit surface travels in a second direction orthogonal to the first direction;
5. The light source device according to claim 1, wherein the wavelength conversion unit converts a part of the light having the first wavelength traveling in the second direction into light having a second wavelength. The first wavelength light is blue light,
The light of the second wavelength is yellow light,
The light source device according to any one of claims 1 to 5, wherein white light can be obtained by mixing colors of the blue light and the yellow light. The wavelength converter is
A light transmissive member capable of transmitting the light of the first wavelength and the light of the second wavelength;
The light source device according to claim 6, further comprising: a phosphor that is included in the light transmission member and is excited by being irradiated with blue light to generate yellow light. An electronic device having a display unit that displays using light from a light source device in a display unit,
An electronic apparatus in which the light source device according to any one of claims 1 to 7 is used as the light source device. The electronic device according to claim 8, wherein the wavelength conversion unit used in the light source device is provided in the display panel.

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