JP6375862B2 - Surface light source device, liquid crystal display device, and electronic apparatus - Google Patents

Description

  The present invention relates to a surface light source device, a liquid crystal display device, and an electronic apparatus.

  Liquid crystal display devices are used as display devices for electronic devices. In recent years, surface light source devices that employ light emitting diodes (LEDs) as light sources have been used as backlights for liquid crystal display devices. The LED used in the surface light source device includes a light output portion that transmits light such as a fluorescent material. The light emitted from the LED is emitted to the outside through this light emitting part. The light emitted from the LED enters the light guide plate from the light incident surface on the side surface of the light guide plate, and is guided to the light output surface of the light guide plate while being totally reflected in the light guide plate. The light guide plate is also referred to as a light guide.

  Conventionally, in an LED used in a surface light source device, the light exit portion is accommodated in a package member having an opening on the front surface, and the light exit portion is accommodated so as to be recessed with respect to the opening of the package member. Therefore, even if the LED and the light guide plate are arranged so as to be in close contact with each other, there is little possibility that the light output portion of the LED directly contacts the light guide plate. In addition, since the light output portion is a recess with respect to the opening of the package member, it is possible to interpose an appropriate air layer between the light output portion of the LED and the light incident surface of the light guide plate ( (See Patent Document 1 and Patent Document 2).

JP 2006-278122 A JP 2012-237826 A

  In a surface light source device that is expected to have high brightness, it is required to mount LEDs at a narrow pitch. In the edge light type surface light source device, conventionally, it has been allowed to arrange a large number of LEDs over a plurality of sides of a frame in response to the need for high brightness. However, in recent years, there is a need for a narrow frame with a narrower frame width in order to realize a smaller and larger display area. Therefore, it is required to concentrate more LEDs on one side and arrange more LEDs at a narrower pitch.

  Therefore, in order to allow more LEDs to be arranged at a narrower pitch, LED miniaturization is promoted. Among LEDs developed for the purpose of downsizing, there is a LED in which the size of the package member is reduced and the light output portion is exposed on the outer surface of the package member. When such an LED is arranged so as to be in close contact with the light guide plate, the light output portion comes into contact with the light guide plate. As a result, there is a risk of scratching the light exit portion. Further, when the light output portion and the light guide plate are in contact with each other, no air layer is interposed between the light output portion and the light incident surface of the light guide plate. By eliminating the air layer, high angle component light that is not totally reflected in the light guide plate enters the light guide plate. As a result, the luminance of the surface light source device may be reduced. Therefore, an object of the present invention is to form a gap of a predetermined distance between the light output portion and the light incident surface of the light guide plate in the LED where the light output portion is exposed on the outer surface of the package member.

The present invention employs the following means in order to solve the above-described problems. That is, the present invention is the following surface light source device.
A light guide plate having a light incident surface on the side, and a light exit portion from which light is emitted are provided on the surface of a predetermined outer surface,
A surface light source device comprising: a light source disposed so that a light exit portion faces a light incident surface of a light guide plate; a substrate on which the light source is mounted; and a frame body surrounding the light guide plate. The surface light source device, wherein at least one of the substrate and the frame has gap forming means that can form a gap of a predetermined distance between the light output part and the light incident surface of the light guide plate.

  According to the surface light source device of the present invention, at least one of the light guide plate, the substrate, or the frame has gap forming means that can form a gap of a predetermined distance between the light output portion and the light incident surface of the light guide plate. Thus, a gap of a predetermined distance can be formed between the light output portion and the light incident surface of the light guide plate. As a result, the present invention can suppress a decrease in luminance of a surface light source device that employs a light source in which a light output portion from which light is emitted is provided on a predetermined outer surface.

The surface light source device according to the present invention may have the following characteristics.
The gap forming means has a plurality of protrusions provided at a predetermined interval on the light incident surface of the light guide plate, and the protrusions are brought into contact with a part of the light output portion of the light source, whereby the light output portion of the light source and the light guide plate A gap of a predetermined distance is formed between the light incident surface.

  According to such an invention, the light projecting portion of the light source and the light incident surface of the light guide plate are brought into contact with a part of the light exit portion of the light source by making a plurality of protrusions provided at predetermined intervals on the light incident surface of the light guide plate A gap of a predetermined distance can be formed between the two.

The surface light source device according to the present invention may have the following characteristics.
The gap forming means has a plurality of protrusions provided at predetermined intervals on the light incident surface of the light guide plate, and the protrusions are brought into contact with portions other than the light output portion of the light source, whereby the light output portion of the light source and the light guide plate A gap of a predetermined distance is formed between the light incident surface.

  According to such an invention, the light emitting portion of the light source and the light incident surface of the light guide plate are brought into contact with a portion other than the light emitting portion of the light source by making a plurality of protrusions provided at predetermined intervals on the light incident surface of the light guide plate. A gap of a predetermined distance can be formed between the two.

The surface light source device according to the present invention may have the following characteristics.
The light source is fixed to the base member on a surface different from the surface on which the light output portion of the light source is provided, and the gap forming means makes light incident on the light output portion of the light source and the light guide plate by bringing the protrusions into contact with the base member. A gap of a predetermined distance is formed between the surface.

  According to such an invention, a plurality of protrusions provided at predetermined intervals on the light incident surface of the light guide plate are brought into contact with the base member, whereby a predetermined amount is provided between the light output portion of the light source and the light incident surface of the light guide plate. Distance gaps can be formed.

The surface light source device according to the present invention may have the following characteristics.
The light guide plate is provided with a press-fitting portion where the base member is pressed against the protrusion by press-fitting the base member in parallel with the light incident surface.

  According to such an invention, the position of the light source is stabilized when the base member is pressed by the press-fitting portion.

The surface light source device according to the present invention may have the following characteristics.
The light source is mounted on the substrate on the surface opposite to the surface having the light output portion of the light source, and the gap forming means has a plurality of protrusions provided at predetermined intervals on the light incident surface of the light guide plate, and protrudes on the substrate. By contacting the parts, a gap of a predetermined distance is formed between the light output part of the light source and the light incident surface of the light guide plate.

  According to such an invention, a plurality of protrusions provided at predetermined intervals on the light incident surface of the light guide plate are brought into contact with the substrate, whereby a predetermined distance is provided between the light output portion of the light source and the light incident surface of the light guide plate. Distance gaps can be formed.

  The gap forming means has a contact portion in the frame body that enables relative positioning of the light incident surface and the frame body by contacting the light incident surface of the light guide plate. The position is managed, and a contact portion is brought into contact with the light incident surface of the light guide plate, thereby forming a gap of a predetermined distance between the light output portion of the light source and the light incident surface of the light guide plate.

  According to such an invention, the contact portion provided on the frame is brought into contact with the light incident surface of the light guide plate, whereby a gap of a predetermined distance is provided between the light output portion of the light source and the light incident surface of the light guide plate. Can be formed.

The surface light source device according to the present invention may have the following characteristics.
The frame has a regulating part that regulates the position of the light source by directly or indirectly contacting the surface opposite to the light emitting part of the light source, and the contact part is directly or indirectly from the light emitting part side of the light source to the light source. A second restricting portion for restricting the position of the light source by contacting the light source.

  According to such an invention, the position of the light source is stabilized by the position of the light source being restricted by the restriction part and the second restriction part provided in the frame.

The surface light source device according to the present invention may have the following characteristics.
The abutting portion has a reflecting portion that reflects light emitted from the surface forming the thickness of the light emitting portion of the light source and makes it incident on the light incident surface.

  According to such an invention, the light emitted from the surface forming the thickness of the light emitting part of the light source is reflected by the reflecting part provided in the contact part and is incident on the light incident surface of the light guide plate, whereby the light source Of the light emitted from the light, the ratio of the light incident on the light guide plate is improved.

The surface light source device according to the present invention may have the following characteristics.
The plurality of light sources are mounted on the substrate on a surface different from the surface having the light output portion of the light source, and the gap forming means has one or more stopper members that are fixed to the substrate and whose positional relationship with the light source is managed. The forming means forms a gap of a predetermined distance between the light output portion of the light source and the light incident surface of the light guide plate by bringing a stopper member into contact with the light incident surface of the light guide plate.

  According to such an invention, a predetermined distance can be formed between the light output portion of the light source and the light incident surface of the light guide plate by bringing the stopper member into contact with the light incident surface of the light guide plate.

The surface light source device according to the present invention may have the following characteristics.
The stopper member is a chip component fixed on the substrate by soldering.

  According to such an invention, the chip component which is a general-purpose component is adopted as the stopper member, so that the procurement of the stopper member is facilitated.

  According to the present invention, a gap of a predetermined distance can be formed between the light output portion of the light source and the light incident surface of the light guide plate. As a result, the present invention can suppress a decrease in luminance of a surface light source device that employs a light source in which a light output portion from which light is emitted is provided on a predetermined outer surface.

FIG. 1 is a perspective view illustrating an example of an LED according to a first comparative example. FIG. 2 is a diagram illustrating an example of the peripheral portion of the LED and the light guide plate in the surface light source device according to the first comparative example. FIG. 3 is an example of an enlarged view of the peripheral portion of the LED and the light guide plate. FIG. 4 is a diagram illustrating an example of an LED according to a second comparative example. FIG. 5 is a diagram illustrating an example of the peripheral portion of the LED and the light guide plate in the surface light source device according to the second comparative example. FIG. 6 is an example of an enlarged view of a contact portion between the LED and the light guide plate. FIG. 7 is a diagram illustrating an example of the arrangement of LEDs and light guide plates in the surface light source device according to the embodiment. FIG. 8 is a diagram illustrating an example of a portion where the LED and the light guide plate face in the surface light source device according to the embodiment. FIG. 9 is an example of an enlarged view of a portion where the LED and the light guide plate face each other. FIG. 10 is a diagram illustrating an example of a graph for comparing luminances of the surface light source device according to the comparative example 2 and the surface light source device of the embodiment. FIG. 11 is a diagram illustrating an example of the arrangement of the LEDs and the light guide plate in the surface light source device according to the first embodiment. FIG. 12 is a diagram illustrating an example of a portion where the LED and the light guide plate are in contact with each other in the first embodiment. FIG. 13 is a diagram illustrating an example of the arrangement of LEDs and light guide plates in the surface light source device according to the second embodiment. FIG. 14 is a diagram illustrating an example of a portion where the LED and the light guide plate are in contact with each other in the second embodiment. FIG. 15 is a diagram illustrating an example of the arrangement of the LEDs and the light guide plate in the surface light source device according to the third embodiment. FIG. 16 is a diagram illustrating an example of a portion where the LED and the light guide plate face in the surface light source device according to the third embodiment. FIG. 17 is a diagram illustrating an example of a protruding portion according to the third embodiment. FIG. 18 is a diagram illustrating an example of the arrangement of LEDs and light guide plates in the surface light source device according to the fourth embodiment. FIG. 19 is a diagram illustrating an example of a portion where the LED and the light guide plate are in contact with each other in the fourth embodiment. FIG. 20 is a diagram illustrating an example of an attaching direction of the FPC board on which the LED is mounted to the light guide plate in the fourth embodiment. FIG. 21 is a diagram illustrating an example of the arrangement of the LEDs, the light guide plate, and the frame in the surface light source device according to the fifth embodiment. FIG. 22 is a diagram illustrating an example of a portion where the frame and the light guide plate are in contact with each other according to the fifth embodiment. FIG. 23 is a diagram illustrating an example of the arrangement of the LEDs, the light guide plate, and the frame in the surface light source device according to the sixth embodiment. FIG. 24 is a diagram illustrating an example of an arrangement of LEDs, a light guide plate, an FPC board, and a stopper member in the surface light source device according to the seventh embodiment. FIG. 25 is a diagram illustrating an example of an FPC board provided with a stopper member according to the seventh embodiment. FIG. 26 is a diagram showing an example of the configuration of a liquid crystal display in which the surface light source device according to the present invention is employed as a backlight. FIG. 27 is a diagram illustrating an example of a smartphone including a liquid crystal display.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiment described below shows an example for carrying out the present invention, and the present invention is not limited to a specific configuration described below. In practicing the present invention, it is preferable to adopt a specific configuration according to the embodiment as appropriate.

<First comparative example>
The surface light source device according to the first comparative example employs an LED in which a fluorescent material is accommodated in an opening of a package member as a light source. Hereinafter, the first comparative example will be described with reference to the drawings.

  FIG. 1 is a perspective view showing an example of an LED 100 according to a first comparative example. The LED 100 includes a package member 101, a fluorescent material 103, and a terminal 104. Although not shown in FIG. 1, the LED 100 includes an LED element, and light emitted from the LED element is emitted to the outside through the fluorescent material 103. In the LED described below, a direction in which light is emitted is a front direction, and the opposite side is a rear direction. Moreover, in LED, let the longitudinal direction of LED be a horizontal direction, and let thickness direction be an up-down direction.

  The package member 101 is an exterior of the LED 100. The package member 101 physically protects the LED 100. An opening 102 is provided on the front surface 102 a of the package member 101. The light from the LED 100 is emitted from the opening 102 toward the outside.

  The terminal 104 is a terminal for mounting the LED 100 on the substrate. Terminals 104 are provided at both ends of the LED 100. In the LED 100, for example, power is supplied from the terminal 104.

  The fluorescent material 103 is a member that utilizes a fluorescent phenomenon caused by light emitted from the LED element included in the LED 100. The fluorescent material 103 is accommodated in the opening 102 so as to be recessed (to be a recess) with respect to the front surface 102 a of the opening 102 provided in the package member 101. The LED 100 emits light in which light from the fluorescence of the fluorescent material 103 and light from the LED element that has passed through the fluorescent material 103 are mixed.

FIG. 2 is a diagram illustrating an example of peripheral portions of the LED 100 and the light guide plate 200 in the surface light source device 300 according to the first comparative example. The fluorescent material 103 of the LED 100 is disposed so as to face the light incident surface 202 of the light guide plate 200. The light emitted from the LED 100 enters the light guide plate 200 from the light incident surface 202. Light incident from the light incident surface 202 is guided to the light exit surface 203 by the light guide plate 200. A brightness enhancement film (BEF) sheet 301 that collects light emitted from the light exit surface 203 is provided on the light exit surface 203 of the light guide plate 200. Hereinafter, in this specification, a direction perpendicular to the light exit surface 203 and directed to the BEF sheet 301 is defined as a front direction of the surface light source device 300.

  The surface light source device 300 serves as a light source that emits light on the surface by guiding the light from the LED 100 to the light exit surface 203 by the light guide plate 200 and condensing the light guided to the light exit surface 203 by the BEF sheet 301.

  In the light guide plate 200, the light from the LED 100 that has entered from the light incident surface 202 spreads throughout the light guide plate 200 due to total reflection in the light guide plate 200. In the light guide plate 200, the light that has been reflected in the light guide plate 200 is guided to the light output surface 203 by providing a part that breaks the condition for partially reflecting light totally.

The BEF sheet 301 collects light emitted from the light exit surface 203 of the light guide plate 200 toward the front of the surface light source device 300. Condensing light by the BEF sheet 301 improves the luminance of the surface light source device 300.

  FIG. 3 is an example of an enlarged view of a portion 90 where the LED 100 and the light guide plate 200 in FIG. 2 are in contact. The LED 100 is in contact with the light incident surface 202 of the light guide plate 200 on the front surface 102a. The fluorescent material 103 is provided so as to be a recess with respect to the front surface 102a. Therefore, the fluorescent material 103 is not in contact with the light incident surface 202 of the light guide plate 200, and the air layer 105 is interposed between the fluorescent material 103 and the light incident surface 202 of the light guide plate 200.

  In the first comparative example, the fluorescent material 103 of the LED 100 and the light guide plate 200 are not in direct contact. Therefore, there is no possibility that the fluorescent material 103 of the LED 100 is damaged by the light guide plate 200. Moreover, the arrow of FIG. 3 has shown an example of the advancing direction of the emitted light from LED100. In the first comparative example, the light emitted from the LED package 100 is refracted by the air layer 105 and enters the light incident surface 202 at an incident angle at which the light is totally reflected in the light guide plate 200.

<Second Comparative Example>
The surface light source device 300 according to the first comparative example employs the LED 100 in which the fluorescent material 103 is accommodated in the opening 102 of the package member 101 as a light source. In the surface light source device according to the second comparative example, an LED having a fluorescent material provided on the front surface of the package member is employed as the light source. The same components as those in the first comparative example are denoted by the same reference numerals, and redundant description is omitted. Hereinafter, the second comparative example will be described with reference to the drawings.

  FIG. 4 is a diagram illustrating an example of the LED 100a in which the fluorescent material 103a is provided on the front surface of the package member 101a. The LED 100a includes a package member 101a, a fluorescent material 103a, a terminal 104a, and a substrate 111. In the LED 100a, the size of the package member 101a is smaller than that of the LED 100 of the first comparative example. In the LED 100a of the second comparative example, the package member 101a has no opening, and the fluorescent material 103a is exposed on the front surface of the package member.

  The terminal 104a is a terminal for mounting the LED 100a on the substrate. The terminals 104a are provided at both lateral ends of the LED 100a. In the LED 100a, for example, power is supplied from the terminal 104a.

  The substrate 111 is provided on the rear surface of the LED 100a. The width of the substrate 111 is wider than the width of the fluorescent material 103a.

  The fluorescent material 103a is different from the fluorescent material 103 in that it is provided on the front surface of the package member 101a.

  FIG. 5 is a diagram illustrating an example of peripheral portions of the LED 100a and the light guide plate 200 in the surface light source device 300a according to the second comparative example. As shown in FIG. 5, in the surface light source device 300 a of the second comparative example, the fluorescent material 103 a of the LED 100 a is in contact with the light incident surface 202 of the light guide plate 200.

  FIG. 6 is an example of an enlarged view of a contact portion 90a between the LED 100a and the light guide plate 200 in FIG. In the LED 100a of the second comparative example, unlike the LED 100 of the first comparative example, the fluorescent material 103a is exposed on the front surface of the package member 101a. Therefore, the fluorescent material 103 a is in contact with the light incident surface 202 of the light guide plate 200. As a result, in the second comparative example, the fluorescent material 103a may be damaged.

In FIG. 6, an example of the traveling direction of the light emitted from the LED 100a is indicated by an arrow. In Comparative Example 2, the light emitted from the LED 100a is directly incident on the light incident surface 202 of the light guide plate 200 without passing through the air layer. As a result, light that is not totally reflected in the light guide plate 200 may enter the light guide plate 200, and the luminance of the surface light source device 300a may be reduced.

<< Embodiment >>
In the surface light source device according to the embodiment, the LED 100a used in the second comparative example is employed as the light source. In the embodiment, a gap of a predetermined distance is formed between the fluorescent material 103a and the light incident surface of the light guide plate by the gap forming means. The same components as those in the first comparative example or the second comparative example are denoted by the same reference numerals, and redundant description is omitted. Hereinafter, embodiments will be described with reference to the drawings.

FIG. 7 is a diagram illustrating an example of the arrangement of the LEDs 100a and the light guide plate 200 in the surface light source device 300b according to the embodiment. In FIG. 7, a plurality of LEDs 100 a are mounted on a flexible printed circuit (FPC) 110. LED1
00a is mounted on the FPC board 110 on its lower surface. The fluorescent material 103 a of the LED 100 a is disposed so as to face the light incident surface 202 of the light guide plate 200. The light emitted from the LED 100 a passes through the light incident surface 202 and enters the light guide plate 200. A gap of a predetermined distance is formed between the LED 100a and the light incident surface 202 of the light guide plate 200 by gap forming means described in Examples 1 to 7 described later. The LED 100a is an example of the “light source” in the present invention. The fluorescent material 103a is an example of the “light emitting part” in the present invention. The FPC board 110 is an example of the “board” in the present invention.

  FIG. 8 is a diagram illustrating an example of a portion where the LED 100a and the light guide plate 200 face in the surface light source device 300b according to the embodiment. As shown in FIG. 8, in the surface light source device 300 b according to the embodiment, an air layer 105 is interposed between the fluorescent material 103 a and the light incident surface 202 of the light guide plate 200.

  FIG. 9 is an example of an enlarged view of a portion 90b facing the LED 100a and the light guide plate 200 in FIG. The fluorescent material 103a of the LED 100a does not contact the light incident surface 202 of the light guide plate 200, and a gap of a predetermined distance is formed. As a result of forming a gap of a predetermined distance, an air layer 105 is interposed between the fluorescent material 103 a and the light incident surface 202 of the light guide plate 200. In FIG. 9, an example of the traveling direction of the light emitted from the LED 100a is indicated by an arrow. Light emitted from the LED 100 a enters the light guide plate 200 from the light incident surface 202 via the air layer 105. The light emitted from the LED 100 a is refracted by the air layer 105 and enters the light incident surface 202 of the light guide plate 200.

  FIG. 10 is a diagram illustrating an example of a graph comparing luminances of the surface light source device 300a according to the second comparative example and the surface light source device 300b of the embodiment. The vertical axis of FIG. 10 indicates the luminance, and the graph of FIG. 10 is a relative graph with the luminance in the case of “with air layer” being 100. In FIG. 10, the direction described as “with air layer” is the measurement result of the surface light source device 300b of the embodiment, and the direction described as “without air layer” is the surface light source of the second comparative example. It is a measurement result of the apparatus 300a.

  Referring to the graph of FIG. 10, the surface light source device 300 b according to the embodiment in which the air layer 105 is interposed between the fluorescent material 103 a and the light incident surface 202 of the light guide plate 200 is more effective in entering the fluorescent material 103 a and the light guide plate 200. It can be seen that the luminance is higher than that of the surface light source device 300a of the second comparative example in which no air layer is interposed between the light surface 202 and the light surface 202.

In the embodiment, a gap of a predetermined distance is formed between the fluorescent material 103a and the light incident surface 202 of the light guide plate 200 by the gap forming means. Therefore, there is no possibility that the fluorescent material 103a is damaged due to contact with the light guide plate 200.

  In addition, as a result of the gap of a predetermined distance being formed, in the surface light source device 300b according to the embodiment, the air layer 105 is interposed between the fluorescent material 103a and the light incident surface 202 of the light guide plate 200. As a result of the air layer 105 being interposed, according to the embodiment, even when the LED 100a in which the fluorescent material 103a is provided on the front surface of the package member 101a is employed as the light source, the surface light source device 300b having high luminance can be provided. The predetermined distance between the fluorescent material 103a and the light incident surface 202 of the light guide plate 200 is preferably as small as possible except for a close state.

  In the embodiment described above, a specific configuration in which a gap of a predetermined distance is formed between the LED 100a and the light incident surface 202 of the light guide plate 200 will be described as Examples 1 to 7 below.

<Example 1>
In Example 1, a plurality of protrusions are provided at predetermined intervals on the light incident surface of the light guide plate. A gap of a predetermined distance can be formed between the fluorescent material 103a and the light incident surface of the light guide plate by bringing the protruding portion into contact with a part of the fluorescent material 103a of the LED 100a. Embodiment 1 will be described below with reference to the drawings.

  FIG. 11 is a diagram illustrating an example of the arrangement of the LEDs 100a and the light guide plate 200a in the surface light source device 300c according to the first embodiment. The light guide plate 200a is different from the light guide plate 200 in that it has a plurality of protrusions 201 at predetermined intervals on the light incident surface 202a.

  A plurality of protrusions 201 are provided on the light incident surface 202a of the light guide plate 200a. The interval between the adjacent protrusions 201 is narrower than the width of the fluorescent material 103a of the LED 100a. Therefore, if it arrange | positions so that LED100a and the light-guide plate 200a may be contacted, the protrusion part 201 will contact | abut to the both ends of the horizontal direction of the fluorescent material 103a. The protrusion 201 is an example of the “projection” in the present invention. Both ends in the horizontal direction of the fluorescent material 103a are an example of “a part of the light emitting portion” in the present invention.

  FIG. 12 is a diagram illustrating an example of a portion where the LED 100a and the light guide plate 200a are in contact with each other in the first embodiment. In Example 1, the protrusion part 201 of the light-guide plate 200a is contact | abutted to the edge part of the fluorescent material 103a of LED100a. Further, in the portion of the fluorescent material 103a that is not in contact with the protruding portion 201, a gap of a predetermined distance is formed between the light entrance plate 202a of the light guide plate 200a. As a result, the air layer 105 is interposed between the fluorescent material 103a and the light incident surface 202a of the light guide plate 200a.

  In Example 1, the protrusion part 201 provided in the light-guide plate 200a was made to contact | abut to the edge part of the fluorescent material 103a of LED100a. As a result, in Example 1, a gap of a predetermined distance can be formed between the fluorescent material 103 and the light incident surface 202a of the light guide plate 200a.

<Example 2>
In Example 1, the protrusion 201 provided on the light guide plate 200a is brought into contact with the end of the fluorescent material 103 of the LED 100a, so that a predetermined distance is provided between the fluorescent material 103a and the light incident surface 202a of the light guide plate 200a. A gap was formed. In Example 2, the protrusion provided on the light incident surface of the light guide plate is brought into contact with the substrate 111 of the LED 100a, so that a gap of a predetermined distance is formed between the fluorescent material 103a and the light incident surface 202a of the light guide plate 200a. Let it form.

FIG. 13 is a diagram illustrating an example of the arrangement of the LEDs 100a and the light guide plate 200b in the surface light source device 300d according to the second embodiment. FIG. 14 is a diagram illustrating an example of a portion where the LED 100a and the light guide plate 200b are in contact with each other in the second embodiment. The light guide plate 200b has a light incident surface 2
02b has a plurality of protrusions 201a provided at a predetermined interval.

  In Example 2, the LED 100a has a substrate 111 on its rear surface. The width of the substrate 111 is wider than the width of the fluorescent material 103a.

  The light guide plate 200b differs from the light guide plate 200a in that it has a protruding portion 201a. A plurality of protrusions 201a are provided on the light incident surface 202b of the light guide plate 200b. The interval between the adjacent protrusions 201a is wider than the width of the fluorescent material 103a of the LED 100a and narrower than the width of the substrate 111. The width of the protruding portion 201a is narrower than the interval between the adjacent LEDs 100a. The protruding amount of the protruding portion 201a is larger than the height from the substrate 111 to the fluorescent material 103a. Therefore, when the LED 100a and the light guide plate 200b are arranged so as to contact each other, the LEDs 100a are arranged one by one between the adjacent protrusions 201a. Further, the protruding portion 201a contacts the substrate 111 of the LED 100a. As a result, a gap of a predetermined distance is formed between the fluorescent material 103a and the light incident surface 202b of the light guide plate 200b. The protrusion 201a is an example of the “projection” in the present invention. The substrate 111 is an example of the “part other than the light exit portion” and the “base member” in the present invention.

  In Example 2, a gap of a predetermined distance is formed between the fluorescent material 103a and the light incident surface 202b of the light guide plate 200b by bringing the protruding portion 201a provided on the light guide plate 200b into contact with the substrate 111 of the LED 100a. be able to.

<Example 3>
In Example 3, the LED 100a is held by the protrusion provided on the light guide plate, and a gap of a predetermined distance is formed between the fluorescent material 103a and the light incident surface of the light guide plate. Hereinafter, Example 3 will be described with reference to the drawings.

  FIG. 15 is a diagram illustrating an example of the arrangement of the LEDs 100a and the light guide plate 200c in the surface light source device 300e according to the third embodiment. FIG. 16 is a diagram illustrating an example of a portion where the LED 100a and the light guide plate 200c face in the surface light source device 300e according to the third embodiment. A surface light source device 300e according to the third embodiment includes a light guide plate 200c and an LED 100a.

  The light incident surface 202c of the light guide plate 200c is provided with a protrusion 201b for positioning the LED 100a. The protrusion 201b includes a protrusion 401a and a protrusion 401b provided at the tip of the protrusion 401a. The protrusion 201b is brought into contact with the LED 100a from the side of the LED 100a having the fluorescent material 103. The protruding amount of the protruding portion 201b is larger than the height from the substrate 111 to the fluorescent material 103a. The interval between the adjacent protrusions 201b is wider than the width of the fluorescent material 103a. The protruding portion 201b2 is provided to face the protruding portion 201b, and comes into contact with the LED 100a from the surface 204 opposite to the surface of the LED 100a having the fluorescent material 103. The position of the LED 100a is determined by being pressed so as to be sandwiched between the protrusions 201b and 201b2. The protruding portions 201b and 201b2 are an example of the “press-fit portion” in the present invention.

  FIG. 17 is a diagram illustrating an example of the protrusions 201b and 201b2 according to the third embodiment. The interval between the protruding portions 201b and 201b2 is formed to be narrower than the thickness of the substrate 111 of the LED 100a. Therefore, the substrate 111 of the LED 100a is press-fitted while crushing the protrusions 201b and 201b2. Therefore, the substrate 111 is held by the elastic force of the protrusions 201b and 201b2, and the position of the LED 100a is determined.

In FIG. 17, the protrusion 201b includes a protrusion 401a and a protrusion 401b. However, the protrusion 201b is not limited to such a shape. Protruding part 201b
For example, the convex portion 401b can be omitted. In this case, the protrusion 401a of the protrusion 201b is brought into contact with the LED 100a.

  In the surface light source device 300e according to the third embodiment, a gap of a predetermined distance can be formed between the fluorescent material 103a and the light incident surface 202c of the light guide plate 200c by bringing the protruding portion 201b and the substrate 111 into contact with each other. Further, the position of the LED 100a is determined by holding the substrate 111 by the protrusions 201b and 201b2.

<Example 4>
In Example 4, the LED 100a is mounted on the FPC board 110 on the rear surface. Embodiment 4 will be described below with reference to the drawings.

  FIG. 18 is a diagram illustrating an example of the arrangement of the LEDs 100a and the light guide plate 200d in the surface light source device 300f according to the fourth embodiment. FIG. 19 is a diagram illustrating an example of a portion where the LED 100a and the light guide plate 200d are in contact with each other in the fourth embodiment. FIG. 20 is a diagram illustrating an example of an attachment direction of the FPC board 110 on which the LED 100a is mounted to the light guide plate 200d according to the fourth embodiment. The light guide plate 200d has a plurality of protrusions 201c provided on the light incident surface 202d at a predetermined interval. The FPC board 110 on which the LED 100a is mounted is mounted so that the fluorescent material 103a of the LED 100a faces the light incident surface 202d of the light guide plate 200d. The protrusion 201c is in contact with the FPC board 110. The FPC board 110 and the protruding portion 201c are bonded by, for example, an adhesive 210. The protrusion 201c is an example of the “projection” in the present invention.

  The light guide plate 200d is different from the light guide plate 200b in that a projection 201c is provided on the light incident surface 202d. A plurality of protruding portions 201c are provided on the light incident surface 202d of the light guide plate 200d. The interval between the adjacent protrusions 201c is wider than the width of the fluorescent material 103a of the LED 100a. The width of the protruding portion 201c is narrower than the interval between the adjacent LEDs 100a. The protruding amount of the protruding portion 201c is larger than the height from the FPC board 110 to the fluorescent material 103a. For this reason, when the LEDs 100a and the light guide plate 200d are disposed so as to contact each other, the LEDs 100a are disposed one by one between the adjacent protrusions 201c. Further, when the LED 100a and the light guide plate 200d are disposed so as to be in contact with each other, the protruding portion 201c contacts the FPC board 110. As a result, a gap of a predetermined distance is formed between the fluorescent material 103a and the light incident surface 202d of the light guide plate 200d.

  In Example 4, the protrusion 201c provided on the light guide plate 200d was brought into contact with the FPC board 110 on which the LED 100a was mounted. As a result, in Example 4, a gap of a predetermined distance can be formed between the fluorescent material 103a and the light guide plate 200d.

<Example 5>
In the fifth embodiment, the light incident surface 202 of the light guide plate 200 is positioned by a contact portion provided on a frame surrounding the light guide plate 200. Embodiment 5 will be described below with reference to the drawings.

  FIG. 21 is a diagram illustrating an example of an arrangement of the LED 100a, the light guide plate 200, and the frame 150 in the surface light source device 300g according to the fifth embodiment. FIG. 22 is a diagram illustrating an example of a portion where the frame 150 and the light guide plate 200 are in contact with each other in the fifth embodiment. A surface light source device 300g according to the fifth embodiment includes a light guide plate 200, a frame 150, and an LED 100a.

The frame 150 is a frame body that surrounds the periphery of the light guide plate 200. The inner surface of the frame 150 is configured to reflect light. The light leaking from the periphery of the light guide plate 200 is reflected and returned to the light guide plate 200. The frame 150 includes an abutting portion 151, a reflecting portion 152, a holding portion 153, and a holding portion 154. The frame 150 is an example of the “frame” in the present invention.

  The abutting portion 151 is in contact with the light incident surface 202 of the light guide plate 200, thereby enabling relative positioning between the light incident surface 202 and the frame 150. The positional relationship between the abutting portion 151 and the fluorescent material 103a is managed, and the abutting portion 151 protrudes from the fluorescent material 103a of the LED 100a to the light incident surface 202 side. The abutting portion 151 is an example of the “contact portion” in the present invention.

  The reflection part 152 is provided on the side surface of the abutting part 151. The reflection unit 152 reflects the light emitted from the side surface 106 which is the surface forming the thickness of the fluorescent material 103 a and makes it incident on the light incident surface 202. In FIG. 22, an example of light output from the side surface 106 and reflected by the reflecting portion is indicated by an arrow. The reflector 152 is an example of the “reflector” in the present invention.

  The holding part 153 regulates the position of the LED 100a by contacting the rear surface of the LED 100a. The holding part 154 regulates the position of the LED 100a by contacting the LED 100a from the fluorescent material 103a side of the LED 100a. The holding unit 153 is an example of the “second regulating unit” in the present invention. The holding part 154 is an example of the “restricting part” in the present invention.

  In the fifth embodiment, the light incident surface 202 is positioned by contacting the contact portion 151 with the light incident surface 202, and the position of the LED 100 a is regulated by the holding portions 153 and 154. As a result, a gap of a predetermined distance is formed between the fluorescent material 103a and the light incident surface 202 of the light guide plate 200.

<Example 6>
In the sixth embodiment, the light incident surface 202 of the light guide plate 200 is positioned by an abutting portion provided on the inner surface of the frame surrounding the light guide plate 200. Embodiment 6 will be described below with reference to the drawings.

  FIG. 23 is a diagram illustrating an example of an arrangement of the LED 100a, the light guide plate 200d, and the frame 150a in the surface light source device 300h according to the sixth embodiment. The surface light source device 300h according to the sixth embodiment includes a light guide plate 200, a frame 150a, and an LED 100a.

  The frame 150a is different from the frame 150 in that it does not have the holding portions 153 and 154 and is provided with an abutting portion 151a instead of the contact portion 151. The abutting portion 151a is provided on the inner surface of the frame 150a. The abutting portion 151 a makes contact with the light incident surface 202 to enable relative positioning of the light incident surface 202 and the frame 150 a. The positional relationship between the abutting portion 151a and the fluorescent material 103a is managed, and the abutting portion 151a is provided closer to the light incident surface 202 than the fluorescent material 103a of the LED 100a. When the abutting portion 151 a is brought into contact with the light incident surface 202, a gap of a predetermined distance can be formed between the fluorescent material 103 a and the light incident surface 202 of the light guide plate 200.

  In the sixth embodiment, a gap of a predetermined distance can be formed between the fluorescent material 103 a and the light incident surface 202 of the light guide plate 200 by the abutting portion 151 a contacting the light incident surface 202.

<Example 7>
In Example 7, the LED 100a is mounted on the substrate 110 on the rear surface. The substrate 110 is provided with one or a plurality of stopper members, and a predetermined distance between the fluorescent material 103 a and the light incident surface 202 of the light guide plate 200 by bringing the light incident surface 202 of the light guide plate 200 into contact with the stopper member. Form a gap of distance. Hereinafter, Example 7 will be described with reference to the drawings.

  FIG. 24 is a diagram illustrating an example of the arrangement of the LED 100a, the light guide plate 200, the FPC board 110, and the stopper member 160 in the surface light source device 300i according to the seventh embodiment. FIG. 25 is a diagram illustrating an example of the FPC board 110 provided with the stopper member 160 according to the seventh embodiment. A surface light source device 300i according to the seventh embodiment includes an LED 100a, a light guide plate 200, an FPC board 110, and a stopper member 160.

  The stopper member 160 regulates the position of the light incident surface 202 by being in contact with the light incident surface 202. The stopper member 160 is provided on the FPC substrate 110 closer to the light incident surface 202 than the fluorescent material 103a. The stopper member 160 is a chip component that is fixed on the FPC board 110 by soldering, for example. However, the stopper member 160 is not limited to a chip component. The stopper member 160 may be a member developed exclusively for the stopper member, for example. In FIG. 24, the stopper member 160 is provided between the LEDs 100a. However, the arrangement of the stopper member 160 is not limited to this type. For example, the stopper members 160 may be provided at both ends of the LEDs 100a arranged in a line.

  In the seventh embodiment, the light incident surface 202 is positioned by contacting the light incident surface 202 with a stopper member 160 provided closer to the light incident surface 202 than the fluorescent material 103a. As a result, a gap of a predetermined distance can be formed between the fluorescent material 103a and the light incident surface 202 of the light guide plate 200.

  The embodiments and modifications disclosed above can be combined. For example, the light incident surface 202 can be positioned by the stopper member 160 described in the seventh embodiment while the position of the LED 100a is regulated by the holding portions 153 and 154 described in the fifth embodiment.

<Application to LCD>
A display device such as a liquid crystal display provided with the surface light source device according to the present invention described above as a backlight can be provided. FIG. 26 is a diagram showing an example of the configuration of a liquid crystal display in which the surface light source device according to the present invention is employed as the backlight 4. FIG. 26 shows main components of the liquid crystal display 5. The liquid crystal display 5 is configured by a liquid crystal panel 50 overlapping the light exit surface of the backlight 4 described above.

  The liquid crystal panel 50 is a display panel that displays light by receiving light emitted from the backlight 4 and applying a voltage to the liquid crystal 51 to increase or decrease the light transmittance. The liquid crystal panel 50 is configured such that a liquid crystal 51 sandwiched between glass plates 52a and 52b is further sandwiched between a pair of polarizing plates 53a and 53b. The light emitted from the backlight 4 passes through each component in the order of the polarizing plate 53a, the glass plate 52a, the liquid crystal 51, the glass plate 52b, and the polarizing plate 53b.

  The liquid crystal display 5 configured as described above can be expected to have a higher luminance while being small and having a narrow frame.

<Application to electronic devices>
Furthermore, electronic devices, such as a smart phone, a digital camera, a tablet terminal, provided with such a liquid crystal display 5 can be provided. FIG. 27 is a diagram illustrating an example of the smartphone 6 including the liquid crystal display 5. An electronic device such as the smartphone 6 can be expected to provide a display with higher image quality.

100, 100a ... LED
101, 101a ... package member 102 ... opening 102a ... front face 103, 103a ... fluorescent material 104, 104a ... terminal 105 ... air layer 106 ... side face 150, 150a ...・ Frames 151, 151a ... Abutting portion 152 ... Reflecting portion 153 ... Holding portion 154 ... Holding portion 110 ... FPC board 111 ... Board 200, 200a, 200b, 200c, 200d ..Light guide plate 201, 201a, 201b, 201c... Projection part 202... Light entrance surface 203... Light exit surface 210 .. Adhesive 204 .. Opposite surface 300, 300a, 300b, 300c , 300d, 300e, 300f, 300g, 300h, 300i ... surface light source device 4 ... backlight 5 ... liquid crystal display 6 ... Smartphone

Claims (4)

A light guide plate having a light incident surface on the side;
A light source that is provided on a surface of a predetermined outer surface to emit light, and the light output unit is disposed so as to face the light incident surface of the light guide plate;
A substrate on which the light source is mounted;
A surface light source device comprising a frame body surrounding the light guide plate,
At least one of the light guide plate, the substrate, or the frame body has a gap forming means that can form a gap of a predetermined distance between the light exit portion and the light incident surface,
The gap forming means has a contact portion in the frame body that enables relative positioning of the light incident surface and the frame body by contacting the light incident surface;
The position of the light source is managed with respect to the contact portion,
By bringing the contact portion into contact with the light incident surface, a gap of a predetermined distance is formed between the light output portion and the light incident surface,
The abutting portion has a reflecting portion that reflects light emitted from a surface forming the thickness of the light emitting portion and makes the light incident on the light incident surface,
The reflection part is disposed closer to the light incident surface of the light guide plate than the light output part ,
Surface light source device. The frame body has a restricting part that restricts the position of the light source by directly or indirectly contacting the surface of the light source opposite to the light exit part,
The contact portion includes a second restricting portion that restricts the position of the light source by directly or indirectly contacting the light source from the light emitting portion side of the light source.
The surface light source device according to claim 1 . A surface light source device according to claim 1 or 2 is provided as a backlight.
Liquid crystal display device. A liquid crystal display device according to claim 3 is provided.
Electronic equipment.

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