JP2006313682A - Light source unit and light source device equipped with this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source unit and a light source device equipped with this, capable of reducing cost by drastically reducing the number of light reflection bodies. <P>SOLUTION: Light reflection faces a, b reflecting emission light emitted from two pairs of light emitting diode lamps 37A in directions opposing to each other are formed on an illumination side of a light guide member 33A, and arranged at such positions that reflects the emission light from the two pairs of light-emitting diode lamps 37A respectively, in a manner of making the reflected light travel inside a first light guide member 33a and a second light guide member 33b in a direction along a light incident face of the illumination object. Therefore, the emission light from each light-emitting diode lamp 37A is reflected at the light reflection face a, b, and a part of each reflected light travels inside the first light guide member 33a and the second light guide member 33b in a direction along a light incident face of a liquid crystal display part 20 while dispersing in total reflection. By the above, a planar light source is obtained on a virtual face parallel with the light-incident face of the liquid crystal display part 20. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light source unit suitable for use in, for example, a backlight illuminator of a liquid crystal television and a light source device including the same.

  2. Description of the Related Art In recent years, liquid crystal displays have gained widespread use mainly for small and medium sized displays because they have advantages such as thinness and low power consumption compared to cathode ray tube (CRT) displays.

  As a light source device in such a liquid crystal display, in consideration of eliminating the adverse effect of mercury gas on the environment (human body), the deterioration of components due to ultraviolet light irradiation is prevented, and the power consumption cost due to the use of an inverter circuit From the viewpoint of reducing the amount of light and obtaining good color reproducibility, a light emitting diode (LED) element is employed instead of the cold cathode fluorescent tube in which mercury gas is enclosed.

  Conventionally, this type of light source device includes a mounting substrate as an element mounting substrate, a side light emitting chip LED (light emitting diode lamp) with a plurality of reflectors arranged in parallel on the element mounting surface of the mounting substrate, The thing provided with the light guide member for guiding the radiated light from light emitting chip LED to the illumination object is proposed (for example, refer patent document 1).

In such a light source device, the side light emitting chip LED on the mounting substrate is turned on, and the lighting light is reflected by the reflector and irradiated into the light guide member, and then diffused in a planar shape within the light guide member. After that, the entire back surface of the liquid crystal panel as the illumination target is illuminated (backlight illumination).
Japanese Patent No. 3472417

  However, according to the light source device shown in Patent Document 1, each side light emitting chip LED has a light reflector (light reflecting surface) that reflects radiated light emitted from the light emitting element. Required the same number of light reflectors (light reflecting surfaces). As a result, there is a problem that the number of light reflectors increases and the cost increases.

  Accordingly, an object of the present invention is to provide a light source capable of greatly reducing the number of light reflectors and thereby reducing the cost by a very simple configuration in which a light reflecting surface is formed on a light guide member. An object is to provide a unit and a light source device including the unit.

(1) To achieve the above object, according to the present invention, there are provided at least two sets of light emitting diode lamps that are arranged adjacent to each other and irradiate an illumination target with white light, and the at least two sets of light emitting diodes. A light source unit for guiding radiated light radiated from the lamp to the illumination target, wherein the two light emitting diode lamps radiate from the illumination target side of the light guide member, respectively. A pair of light reflecting surfaces are formed to reflect the emitted light in opposite directions, and the pair of light reflecting surfaces reflect the emitted light from the two sets of light emitting diode lamps, respectively. A light source unit is provided, wherein the light source unit is disposed at a position such that light travels in the light guide member in a direction along a light incident surface of the illumination target.

(2) In order to achieve the above object, the present invention provides a light source device including a plurality of light source units arranged in parallel in the same plane, wherein the light source unit is the light source unit described in (1) above. A light source device is provided.

  According to the present invention, the number of light reflectors can be greatly reduced, and the cost can be reduced.

[First embodiment]
FIG. 1 is a diagram for explaining a liquid crystal television provided with a light source device according to a first embodiment of the present invention. Fig.1 (a) is a front view, FIG.1 (b) is the sectional view on the AA line of Fig.1 (a). FIG. 2 is a front view for explaining the light source device according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view for explaining the light source device according to the first embodiment of the present invention.

[Overall configuration of LCD television]
1 (a) and 1 (b), a liquid crystal television (television) denoted by reference numeral 1 includes a main body portion 10 as an exterior body, a liquid crystal display portion 20 for displaying an image on the front surface of the main body portion 10, It is generally composed of a backlight unit 30 for illuminating the back surface (light incident surface) of the liquid crystal display unit 20.

  The main body 10 includes a housing 11 that houses various television components and a leg 12 that projects downward from the housing 11. The housing 11 has a through window 11A that opens forward, and is entirely formed of a substantially rectangular box made of a metal such as an aluminum alloy. The leg body 12 has a leg portion 12A and a seat portion 12B, is disposed below the housing 11, and is configured to hold the main body portion 10, the liquid crystal display portion 20, the backlight portion 30, and the like.

  The liquid crystal display unit 20 is composed of a transmissive liquid crystal panel having a liquid crystal display surface 20A (light emitting surface), and is disposed in front of the through window 11A as shown in FIG. 52 is attached. The illumination light from the backlight unit 30 incident on the light incident surface is converted into light corresponding to the image signal, and the converted light is emitted from the liquid crystal display surface 20A as transmitted light.

  The backlight unit 30 includes a light source unit group 32 for illuminating the liquid crystal display unit (illumination target) 20 and a diffusion plate 51 for reducing luminance unevenness of illumination light emitted from the light source unit group 32. It is housed and held in the housing 11.

<Configuration of light source unit group 32>
As shown in FIG. 2, the light source unit group 32 includes light source units 32 </ b> A (only two are shown) that are parallel (adjacent) in the horizontal direction, and is disposed at a position facing the back surface of the diffusion plate 51. Since the light source unit 32A has substantially the same configuration, only the configuration of one light source unit 32A will be described. The light source unit 32A includes 10 sets of red light emitting diode elements, green light emitting diode elements, and blue light emitting diode elements described later. And a light-emitting diode lamp group 37.

  As shown in FIG. 2, the light emitting diode lamp group 37 is arranged in parallel in a direction (vertical direction) perpendicular to the adjacent direction of the light source unit 32A. These light emitting diode lamp groups 37 are arranged close to each other as shown in FIG.

  Since the light-emitting diode lamp group 37 has substantially the same configuration, only the configuration of one set of light-emitting diode lamp group 37 will be described. The light-emitting diode lamp group 37 includes five sets of light-emitting diode lamps 37A on the element mounting substrate 38. It is mounted on. These light emitting diode lamps 37A are arranged in parallel in the direction adjacent to the light source unit 32A.

  Since the light emitting diode lamp 37A has substantially the same configuration, only the configuration of the pair of light emitting diode lamps 37A will be described. The light emitting diode lamp 37A is adjacent to the light source unit 32A (lateral direction) as shown in FIG. A plurality of types of light emitting diode elements 39 to 41 (red light emitting diode element 39, green light emitting diode element 40, blue light emitting diode element 41) arranged in parallel to each other and connected to a power supply substrate (not shown) via an element mounting substrate 38. Has been. And it is comprised so that white light may be irradiated to the back surface (light incident surface) of the liquid crystal display part (illumination object) 20.

  The element mounting substrate 38 has a circuit pattern surface 38A on the element mounting side, and is entirely formed of an aluminum base substrate or a ceramic substrate having a substantially planar shape. The element mounting substrate 38 may be another substrate such as a glass epoxy substrate. In this case, it is preferable to take heat dissipation measures such as disposing a heat conductive member such as a thermal pad on the back side of the element mounting substrate 38.

<Configuration of light guide member group 33>
As shown in FIG. 2, the light guide member group 33 includes light guide members 33 </ b> A adjacent in the vertical and horizontal directions, is disposed behind the diffusion plate 51, and is mounted on the back surface of the housing 11 via the heat sink group 34. ing.

  Since the light guide member 33A has substantially the same configuration, only the configuration of one light guide member 33A will be described. The light guide member 33A includes 10 groups of light emitting diode lamp groups in the light source unit 32A as shown in FIG. 37, divided into two light guide members (first light guide member 33a and second light guide member 33b) corresponding to two sets of light emitting diode lamp groups 37 (light emitting diode elements 41 in FIG. 3) that are close to each other. Has been.

  The light guide members 33a and 33b are each formed of a plate-like light-transmitting member made of an organic material such as PMMA (polymethyl methacrylate) resin or an inorganic material such as glass. On the side to be illuminated of the light guide members 33a and 33b, there are two sets of light-emitting diode lamp groups 37 (light-emitting diode elements 41 in FIG. 3) that are radiated from the light-emitting diode elements 41, respectively. A pair of light reflecting surfaces a and b composed of 45 ° inclined surfaces that reflect the light beams in the opposite directions are formed.

  The pair of light reflecting surfaces a and b reflect the radiated light from the two sets of light emitting diode lamp groups 37 (light emitting diode elements 41 in FIG. 3), and each of the reflected light follows the light incident surface of the liquid crystal display unit 20. The light guide members 33a and 33b are disposed in positions that travel in the direction (the side of the light emitting diode element 41 in FIG. 3).

<Configuration of heat sink group 34>
The heat sink group 34 includes heat sinks 34 </ b> A arranged in parallel in the vertical and horizontal directions, is disposed behind the light guide member group 33, and is fixed in the housing 11.

  Since the heat sink 34A has substantially the same configuration, only the configuration of one heat sink 34A will be described. As shown in FIG. 3, the heat sink 34A includes two sets of light emitting diode lamp groups close to each other among the light emitting diode lamp groups 37. 37, and a holding body 34b for holding the boxed box 34a in the casing 11, and the whole is formed of a heat conductive member such as an aluminum alloy or a copper alloy. . The heat generated from the light-emitting diode lamp group 37 is dissipated to the surroundings and is conducted to the housing 11.

(Configuration of diffusion plate 51)
As shown in FIG. 3, the diffusing plate 51 is disposed in the front region of the backlight unit 30 and is attached to the opening peripheral edge of the through window 11A via the bracket 21, and is light transmissive such as PET (polyethylene terephthalate). It is formed of a heat resistant member made of a resin material. And the illumination light radiated | emitted from the light source unit group 32 is spread | diffused inside, and as mentioned above, it is comprised so that the brightness nonuniformity may be reduced. The material of the diffusing plate 51 may be any other material as long as it is light transmissive and does not deform or deteriorate due to heat generated by light emission from the light source unit group 32.

[Operation of Light Source Unit Group 32]
As shown in FIG. 3, when a voltage is applied to the light emitting diode lamp group 37 from the power supply substrate, the light emitting diode elements 39 to 41 emit light in the light emitting layer, and radiated light is emitted from the light emitting diode elements 39 to 41. . Next, the emitted light from the light emitting diode elements 39 to 41 in each light emitting diode lamp group 37 is reflected by the light reflecting surface a of the first light guide member 33a and the light reflecting surface b of the second light guide member 33b. Part of the reflected light travels while being totally reflected and diffused in the first light guide member 33a and the second light guide member 33b in a direction along the light incident surface of the liquid crystal display unit 20. Therefore, it is possible to obtain a planar light source having uniform luminance and good color mixing in a virtual plane parallel to the light incident surface of the liquid crystal display unit 20. Thereafter, radiated light from the light emitting diode elements 39 to 41 enters the diffusion plate 51, and the incident light is further diffused in the diffusion plate 51 to irradiate the liquid crystal display unit 20 as white light.

[Effect of the first embodiment]
According to the first embodiment described above, the following effects can be obtained.

(1) The radiated light from the light emitting diode elements 39 to 41 in each light emitting diode lamp group 37 is opposite to each other on the light reflecting surface a of the first light guide member 33a and the light reflecting surface b of the second light guide member 33b. A part of each reflected light is reflected and travels in the direction along the light incident surface of the liquid crystal display unit 20 while being totally reflected and diffused in the first light guide member 33a and the second light guide member 33b. Thereby, since a planar light source can be obtained in a virtual plane parallel to the light incident surface of the liquid crystal display unit 20, the number of light reflectors can be greatly reduced, and the cost can be reduced. it can.

(2) Since the light emitting diode lamp group 37 can be arranged linearly (in the parallel direction of the light source unit 32A) to obtain a uniform light emitting surface, the number of light emitting diode lamps per unit area can be reduced. Luminous efficiency can be increased.

[Second Embodiment]
FIG. 4 is a cross-sectional view for explaining the light source device according to the second embodiment of the present invention. 4, the same members as those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4, the light source unit group 32 as the light source device shown in the second embodiment is characterized in that the shape of the light guide member 72 is different.

  For this reason, on the illumination target side portion of the light guide member 72, two groove walls 72a made of curved surfaces (shape surfaces that draw a part of a parabola) that are separated from the light emitting diode lamp side toward the illumination target side. A concave groove 72A having a V-shaped cross section 72b is provided. On both groove walls of the concave groove 72A, there are two sets of light-emitting diode lamp groups 37 (light-emitting diode elements 41 in FIG. 4), and radiated lights respectively emitted from the light-emitting diode elements 41 are opposite to each other. Light reflecting surfaces a and b that reflect in the direction are provided.

[Effect of the second embodiment]
According to the second embodiment described above, when a voltage is applied to the light emitting diode lamp group 37 from the power supply substrate, the light emitting diode elements 39 to 41 emit light in the light emitting layer, and the light emitting diode elements 39 to 41 emit light. Synchrotron radiation is emitted. Next, the emitted light from the light emitting diode elements 39 to 41 in each light emitting diode lamp group 37 is reflected by the light reflecting surfaces a and b of the light guide member 72, and a part of each reflected light is light of the liquid crystal display unit 20. The light guide member 72 is totally reflected in the direction along the incident surface and travels while being more effectively diffused. Therefore, it is possible to obtain a planar light source having uniform luminance and good color mixing in a virtual plane parallel to the light incident surface of the liquid crystal display unit 20.

  As mentioned above, although the light source device of this invention was demonstrated based on said each embodiment, this invention is not limited to each said embodiment, In the range which does not deviate from the summary, it implements in various aspects. For example, the following modifications are possible.

(1) The above-described light-emitting diode lamp 37A includes light-emitting diode elements 39 to 41 (red light-emitting diode element R, green light-emitting diode element G, and blue light-emitting diode element B) arranged in parallel in the adjacent direction of the light source unit 32A (R · G · B) has been described, but the present invention is not limited to this, for example, (G · R · B · G) or (G · R · B · R · G) parallel to the adjacent direction of the light source unit 32A It may be composed of

(2) The number of the light source units 32A in the present invention is not particularly limited, and can be appropriately changed according to the aspect ratio of the liquid crystal display surface 20.

(A) And (b) is the front view and sectional drawing shown in order to demonstrate the liquid crystal television provided with the light source device which concerns on the 1st Embodiment of this invention. The front view shown in order to demonstrate the light source device which concerns on the 1st Embodiment of this invention. Sectional drawing shown in order to demonstrate the light source device which concerns on the 1st Embodiment of this invention. Sectional drawing shown in order to demonstrate the light source device which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal television, 10 ... Main-body part, 11 ... Housing | casing, 11A ... Through-hole window, 12 ... Leg, 12A ... Leg part, 12B ... Seat part, 20 ... Liquid crystal display part, 20A ... Liquid crystal display surface, 32 ... Light source Unit group, 32A ... light source unit, 33 ... light guide member group, 33A, 72 ... light guide member, 33a ... first light guide member, 33b ... second light guide member, 34 ... heat sink group, 34A ... heat sink, 37 ... Light emitting diode lamp group, 37A ... Light emitting diode lamp, 38 ... Element mounting substrate, 38A ... Circuit pattern surface, 39 ... Red light emitting diode element, 40, ... Green light emitting diode element, 41 ... Blue light emitting diode element, 51 ... Diffuser plate, 52 ... Beef plate, 72A ... concave groove, 72a, 72b ... groove wall, a, b ... light reflecting surface

Claims (6)

At least two sets of light emitting diode lamps, each arranged adjacent to each other, for illuminating the illumination object with white light;
A light source unit comprising a light guide member for guiding radiation emitted from the at least two sets of light emitting diode lamps to the illumination target,
A pair of light reflecting surfaces for reflecting radiated light emitted from the two sets of light emitting diode lamps in opposite directions are formed on the side to be illuminated of the light guide member,
The pair of light reflecting surfaces respectively reflect the radiated light from the two sets of light emitting diode lamps so that each reflected light travels in the light guide member in a direction along the light incident surface of the illumination target. The light source unit is characterized by being arranged at various positions. The light guide member is divided into a first light guide member and a second light guide member corresponding to the two sets of light emitting diode lamps,
The light source unit according to claim 1, wherein the first light guide member and the second light guide member are provided with the pair of light reflecting surfaces by providing inclined surfaces, respectively.   The light source unit according to claim 2, wherein the light reflecting surface is obtained by subjecting the light guide member to a rough surface treatment.   The light source unit according to claim 1, wherein the pair of light reflecting surfaces are formed by providing a concave groove having a V-shaped cross section in the light guide member.   5. The light source unit according to claim 4, wherein the concave groove has two groove walls formed of curved surfaces that are separated from each other from the light emitting diode lamp side toward the illumination target side. A light source device comprising a plurality of light source units arranged in parallel in the same plane,
The light source unit is a light source unit according to any one of claims 1 to 5.

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