JP6277416B2 - Lighting device - Google Patents

Description

  The present invention relates to an optical component of an LED lighting device using an LED (light emitting diode) as a light source.

  In a thin backlight or lighting device using an LED light source, it is required to emit light with a wide light emitting surface range uniformly and thinly and without a frame. There is also a need for thin lighting that emits light uniformly and has a wide light emitting area in lighting devices.

  In a conventional LED lighting device, there is Patent Literature 1 as a configuration that shines the entire front surface. A conventional LED lighting device of Patent Document 1 will be described with reference to FIG. FIG. 6 is a cross-sectional view of a conventional lighting device 101. An LED light source 21 is disposed on the back surface of the transparent light guide plate 22. On the light irradiation surface of the light guide plate 22 facing the LED light source 21, a light incident prism 28 having a vertex right above the light emission center of the LED light source 21 is formed. A convex fine prism 23 is formed outside the reflecting surface of the light incident prism 28. On the back surface of the light guide plate 22, a plurality of concave fine prisms 24 are formed inside.

  The LED light source 21 is mounted on a substrate 30, and the substrate 30 and the light guide plate 22 are set in a housing 25. On the back surface of the light guide plate 22, a reflection plate 27 is provided for emitting light in the emission direction. Further, a reflection sheet 26 for returning light leaking from the side surface direction of the light guide plate 22 into the light guide plate is attached to the inner surface of the side surface of the housing.

  With this configuration, by providing the light diffusion plate 29 on the light irradiation surface side of the light guide plate 22, the direct illumination type illumination device 101 can be realized using the LED light source 21. As a result, the lighting device 101 is thin and light, and at the same time, the frame can be eliminated, and the above-described problem can be solved.

JP 2005-322549 A

  However, the illumination device 101 of Patent Document 1 emits light only in a planar shape. Further, since the left and right ends of the light guide plate 22 are flat, there is light leakage from the end portions. In addition, strong light is generated from the terminal portion of the light guide plate 22 and bright line unevenness occurs.

  In order to solve the above-mentioned problem, a plurality of light emitting diodes arranged, a first curved portion is located above the plurality of light emitting diodes, a planar portion connected to the first curved portion is located, and a second connected to the planar portion A light guide plate including a curved portion; a first reflecting portion located on a first side of the plurality of light emitting diodes; and a second side located on a second side opposite to the first side of the plurality of light emitting diodes. The first reflecting portion on the first side surface side and the second reflecting portion on the second side surface side are each convex with respect to the light emitting diode, and a plurality of light emitting portions An illuminating device having a recess between the diodes is used.

In an illumination device using LEDs, the upper surface and side surfaces can be illuminated uniformly.

(A) Sectional view of lighting device of embodiment 1 of the present invention, (b) Perspective view of lighting device of embodiment 1 of the present invention, (c) to (d) Illumination of embodiment 1 of the present invention Plan view of the back side of the light guide plate in the device (A) The top view of the state which does not have the light-guide plate of an illuminating device of Embodiment 1 of this invention, and a diffusion plate, (b) AA 'sectional drawing of (a), (c) BB' sectional drawing of (a). (A) Plan view of the second embodiment of the present invention without a diffusion plate and a light guide plate (b) AA ′ sectional view of (a), (c) BB ′ sectional view of (a) (A) Cross-sectional view of lighting device 100 according to Embodiment 3 of the present invention, (b) Perspective view of Embodiment 3 of the present invention, (c) Diffusion plate of Embodiment 3 of lighting device 100 of the present invention Plan view with no cross section and light guide plate The cross section of the diffusion plate of Embodiment 2 of this invention, and the top view of a state without a light-guide plate Sectional drawing of the illuminating device 100 of the conventional patent document 1

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
First, the lighting apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 (a) to 1 (d). Fig.1 (a) is sectional drawing which shows the illuminating device 100 of Embodiment 1 of this invention. FIG. 1B is a perspective view of the illumination device 100 as viewed from the exterior, and is covered with a diffusion plate 55. A broken line shows the state of each internal member in the covered state.

  The lighting device 100 includes a light guide plate 51, LEDs 52, an inner reflection member 53, an outer reflection member 56, a substrate 54, and a diffusion plate 55.

<Light guide plate 51>
As shown in FIG. 1A, the light guide plate 51 receives the light from the LED 52 therein, bends in a horizontal direction 51B, a horizontal plane portion 51C connected to the bend 51B, and the light guide plate 51. And a bent portion 51A which is one end. At the bent portion 51B, the light is reflected by total reflection and transmitted to the flat portion 51C. The light is also bent by total reflection at the bent portion 51A.

  A concave conical prism 57 is provided on the back surface and the lower surface of the flat portion 51C. Light is reflected at that portion, and light is emitted upward.

  FIG. 1C is a part of a plan view of the light guide plate 51 as viewed from the back side, and the conical prism 57 is provided in the flat portion 51C.

  The light from the LED 52 travels through the bent portion 51B by total reflection, and is reflected by the conical prism 57 or the triangular prism 58 of the flat portion 51C toward the emission surface. A conical prism 57 or a triangular prism 58 is provided so that light is emitted uniformly. The depth of the conical prism 57 is 0.1 mm to 0.7 mm, and the pitch is arranged at regular intervals. In order to make the emission of light uniform, the pitch may be varied to make the depth constant.

  The reason for setting to 0.1 mm to 0.7 mm is as follows. If it is smaller than 0.1 mm, the luminance is low and the influence on the depth error is large, which is not preferable. On the other hand, when the thickness exceeds 0.7 mm, when the shape is formed by molding using a mold, the mold release resistance is large, and deformation is likely to occur.

  In the case of variable pitch, the further away from the LED 52, the narrower the pitch and the denser the prism grooves. On the other hand, if the pitch is variable and the depth is constant, when molding is performed using a mold, the balance of mold release resistance is improved and deformation is difficult to occur.

  FIG.1 (d) shows the modification of FIG.1 (c). Instead of the conical prism 57, a triangular prism 58 which is a triangular prism groove is provided. The triangular prism 58 has a depth of 10 to 50 μm and is arranged at a constant pitch. In order to make light emission uniform, the pitch depth may be variable.

  The reason for 10 μm to 50 μm is as follows. If it is smaller than 10 μm, the influence of the depth error on the luminance is large, which is not preferable. On the other hand, when the thickness exceeds 50 μm, the mold release resistance is large and deformation is likely to occur when forming a shape by molding using a mold.

  The depth of the triangular prism 58 increases as the distance from the LED 52 increases. In the case of variable pitch, the pitch needs to be decreased as the distance from the LED 52 increases. When performing luminance control in a short light emission range, it is necessary to use a very fine pitch if the pitch is variable. On the other hand, when the pitch is constant and the depth is variable, the depth control is performed and the brightness control is easy.

<Inner reflection member 53>
As shown in FIG. 1A, the inner reflecting member 53 has a curved inner surface of the bent portion 51A of the light guide plate 51 and a curved reflecting surface 53A having an opposite shape. Similarly, the LED 52 side of the inner reflecting member 53 has a curved reflecting surface 53B having a shape opposite to the inner curved surface of the bent portion 51B of the light guide plate 51. The reverse shape means that both are point-symmetric shapes. However, it does not have to be exactly the same shape. The curved surface 51A and the curved reflecting surface 53A form an elliptical columnar space with concave shapes. The same applies to the inner curved surface of the bent portion 51B and the curved reflecting surface 53B. In this space, light is emitted upward.

  The inner reflection member 53 is a member that reflects light. The conical prism 57 (FIG. 1C) and the triangular prism 58 (FIG. 1D) are not formed in the bent portion 51A and the bent portion 51B of the light guide plate 51. Instead, light can be emitted upward from each pair of the curved reflecting surface 53B and the bent portion 51B, and each pair of the curved reflecting surface 53A and the bent portion 51A. The curved reflecting surface 53B and the curved reflecting surface 53A may have a concave shape that reflects light upward.

<Substrate 54>
The board 54 has a plurality of LEDs 52 mounted in a row. It is a rectangular plate having a thickness of 1 mm, and a circuit pattern for causing the LED 52 to emit light is formed. The substrate thickness is set to 0.5 to 1.0 mm in consideration of heat dissipation and strength in reducing the thickness of the lighting device.

<Diffusion plate 55>
The diffusing plate 55 has a box shape and is configured to cover the surface (upper surface) serving as the main light emitting direction of the LED 52 and the side surface direction in order to make the light from the light guide plate 51 more uniform in appearance. The cover color is milky white and the transmittance is 60 to 90%. The diffusion plate 55 has a function of diffusing light from the light guide plate, and a diffusion material is mixed in the material.

  This diffusing material has the property of absorbing light, and the transmittance varies depending on the amount of the diffusing material. Considering the balance between the light use efficiency in actual use of the lighting device 100 and the light diffusibility for uniform light emission, the amount of the diffusing material of the diffusion plate 55 ranges from 60% to 90% in terms of transmittance. Selected.

<Outside reflection member 56>
As shown in FIG. 1A, an outer reflection member 56 is provided outside the light guide plate 51. The outer reflecting member 56 also reflects light. A space is formed by the outer reflection member 56, the inner reflection member 53, the LED 52, and the light guide plate 51. Use the light in the space effectively. That is, the light of the LED 52 is guided to the light guide plate 51 without waste.

<Shapes of Inner Reflecting Member 53 and Outer Reflecting Member 56>
The shapes of the inner reflecting member 53 and the outer reflecting member 56 are shown in FIGS. 2 (a) to 2 (c). FIG. 2A is a plan view of the lighting device 100 excluding the light guide plate 51. 2B is an AA ′ sectional view including the light guide plate 51, and FIG. 2C is a BB ′ sectional view including the light guide plate 51.

  With respect to the shape of the surface where the inner reflecting member 53 and the outer reflecting member 56 face each other, a protrusion is formed at a portion close to the LED 52, and a portion away from the LED 52 (between the LEDs 52) is recessed. That is, there is a protrusion where the LED 52 faces (opposites). There is a recess between the LEDs 52.

  Some of the light from the LED 52 leaks without being introduced into the light guide plate 51. As a result, there is a strong light of the LED 52 near the LED 52, and the light is weak at a position away from the LED 52 (between the LEDs 52). In order to eliminate this influence, protrusions are provided on the inner reflecting member 53 and the outer reflecting member 56 near the LED 52. On the other hand, a recess is provided between the LEDs 52. As a result, light is emitted uniformly.

<Material and dimensions>
The material of the light guide plate 51 is a molded product of a transparent acrylic material. The inner reflecting member 53 and the outer reflecting member 56 are white resin. The diffusion plate 55 is made of a material containing an acrylic or polycarbonate diffusing agent. In the illumination device 100 shown in FIG. 1A, the thickness of the light guide plate 51 (planar portion 51C) is 1.5 mm. The height H including the bent portion 51A and the bent portion 51B is 3.0 mm. A distance T (FIG. 1 (a)) from the plane of the end of the bent portion 51A to the inner surface of the diffusion plate 55 is 4.3 mm. The difference between the distance T and the height H is a difference D.

  The difference D needs to be greater than a certain range. The reason is that light emitted from the end planes of the bent portions 51 </ b> A and 51 </ b> B is reflected on the inner reflection member 53 and light emitted from the flat portion 51 </ b> C of the light guide plate 51 is uniform on the diffusion plate 55. This is because it is necessary to become.

  Further, the difference D is preferably larger than the pattern pitch of the planar portion 51C of the light guide plate 51 (the pitch of the conical prism 57 (FIG. 1C) and the triangular prism 58 (FIG. 1D)).

The reason is that the spread angle of the light guide plate 51 by the prism is 40 ° to 45 ° on one side. On the other hand, if the distance of the difference D equivalent to the prism pattern pitch is taken, the light from each prism pattern spreads in the same range as the prism pattern pitch. This is because light overlaps and pattern unevenness does not occur.

The light reflected on the curved reflecting surface 53A has a directivity, spreads 60 ° on one side,
The light reflected by the curved reflecting surface 53A can illuminate the side surface direction.

  The difference D is provided so that the light hitting the curved reflecting surface 53A is uniformly emitted from the upper surface and the side surface of the diffusion plate 55. The difference D between the inner surface of the diffusion plate 55 and the upper surface of the light guide plate 51 secures the distance between the diffusion plate 55, the bent portion 51A, and the bent portion 51B.

<Effect>
By employing the structure of the first embodiment, the lighting device 100 that can uniformly illuminate the upper surface and the side surface of the diffusion plate 55 is provided, whereas the side surface of the diffusion plate 55 has not conventionally emitted light. it can.

(Embodiment 2)
The second embodiment is an example in which the first embodiment is partially changed. The parts not described are the same as those in the first embodiment.

  Embodiment 2 of the present invention will be described with reference to FIG. 3A to FIG. 3C for an inner reflection member 53 that is partially changed in form.

  FIG. 3A is a plan view in a horizontal plane of the lighting device 100 from which the diffusion plate 55 and the light guide plate 51 are removed. 3B is a cross-sectional view taken along line AA ′ in FIG. 3A, and FIG. 3C is a cross-sectional view taken along line BB ′ in FIG.

  The inner reflection member 53 has a curved reflection surface 53 </ b> A on the upper side surface thereof changed in the arrangement direction of the LEDs 52 to form a wave-like reflection surface 59. The curved surface of the wave reflection surface 59 is formed in a wave shape in accordance with the intensity of light from the LED 52.

  That is, the inner reflection member 53 forms a convex portion near the LED 52 (FIG. 3B), and forms a concave portion far from the LED 52 (FIG. 3C). Similar to FIG. 2, that is, there is a protrusion where the LED 52 is faced (opposed). There is a recess between the LEDs 52.

  The light from the light source of the LED 52 spreads substantially concentrically around the light source. The curved surface position of the wave-like reflecting surface 59 is changed depending on the position from the LED 52 so that the light is uniformly irradiated. This ensures the uniformity of the light emission state of the side surface on the side that becomes the final end of the light guide plate 51 when viewed from the LED 52.

Matters not described are the same as those in the first embodiment.
<Effect>
By employing the structure of the second embodiment, the lighting device 100 that can uniformly illuminate the upper surface and the side surface of the diffusion plate 55 is provided, while the side surface of the diffusion plate 55 has not conventionally emitted light. it can.

(Embodiment 3)
Illumination device 100 according to Embodiment 3 of the present invention will be described with reference to FIGS. 4 (a) to 4 (c). Matters not described are the same as those in the first and second embodiments.

  FIG. 4A is a cross-sectional view showing lighting device 100 according to Embodiment 3 of the present invention. FIG.4 (b) is the perspective view seen from the external appearance of the illuminating device 100 of this invention. A broken line shows arrangement | positioning of each internal member in the covered state. FIG. 4C is a plan view of the lighting device 100 with the light guide plate 51 removed.

  The illumination device of the third embodiment has a structure in which the left side portion of the first embodiment is also provided on the right side portion. As a difference, the light of the LED 52 enters the bent portion 51B of the light guide plate 51, and then splits in two directions left and right. The subsequent steps are the same as in the first embodiment.

A space is formed by the LED 52, the two inner reflection members 53, and the bent portion 51B of the light guide plate 51. The light in the space is allowed to enter the bent portion 51B without leaking.
<Effect>
By employing the structure of the third embodiment, the lighting device 100 that can uniformly illuminate the upper surface and the side surface of the diffusion plate 55 is provided, whereas the side surface of the diffusion plate 55 does not emit light conventionally. it can.

(Embodiment 4)
Embodiment 4 of the present invention will be described with reference to FIG. FIG. 5 is a plan view of the lighting device 100 with the diffusion plate 55 and the light guide plate 51 removed.

  The lighting device of Embodiment 4 has a structure in which the left side portion is also provided on the right side portion in the lighting device 100 of FIG. The pitch of the LEDs 52 is arranged in a straight line. An inner reflecting member 53 having an inner curved surface of the bent portion 51A that is the final end in one direction when viewed from the LED 52 of the light guide plate 51 and a curved reflecting surface 53A in which the unevenness is reversed is provided.

  The curved surface of the curved reflecting surface 53A is formed on the wave-like reflecting surface 59 in accordance with the intensity of light from the LED 52. When viewed from the LED 52 of the light guide plate 51, an inner reflection member 53 having an inner curved surface of the bent portion 51A that is the final end in the other direction and a curved wavy reflective surface 59 in which the unevenness is reversed is provided.

  With this configuration, it is possible to provide the lighting device 100 that can obtain a more uniform side light emission state. Matters not described are the same as in the second embodiment.

Note that the above embodiments can be combined.
<Effect>
By employing the structure of the fourth embodiment, the lighting device 100 that can uniformly illuminate the upper surface and the side surface of the diffusion plate 55 is provided, whereas the side surface of the diffusion plate 55 does not emit light conventionally. it can.

Can be widely used as a lighting device.

21 Light source 22 Light guide plate 23 Fine prism 24 Fine prism 25 Case 26 Reflective sheet 27 Reflective plate 28 Light incident prism 29 Light diffusing plate 30 Substrate 51 Light guide plate 51A Bent part 51B Bent part 51C Plane part 52 LED
53 inner reflecting member 53A curved reflecting surface 53B curved reflecting surface 54 substrate 55 diffuser plate 56 outer reflecting member 57 conical prism 58 triangular prism 59 wavelike reflecting surfaces 100, 101 illuminating device

Claims (6)

A plurality of light emitting diodes arranged;
A light guide plate including a first curved portion on top of the plurality of light emitting diodes, a planar portion connected to the first curved portion, and a second curved portion connected to the planar portion;
A first reflecting portion located on a first side surface of the plurality of light emitting diodes at a lower portion of the light guide plate;
A second reflecting portion located on a second side facing the first side of the plurality of light emitting diodes;
Have
The end on the first side surface side of the first reflecting portion and the end portion on the second side surface side of the second reflecting portion are respectively convex portions with respect to the light emitting diodes, and between the plurality of light emitting diodes. However, the illumination device is characterized by being a recess. The lighting device according to claim 1, wherein a prism or a recess is formed on a lower surface of the flat portion. 3. The illumination device according to claim 1, wherein one end portion of the upper surface of the first reflecting portion is a convex portion with respect to the light emitting diode and a concave portion between the plurality of light emitting diodes. A plurality of light emitting diodes arranged in a row ;
A first curved portion located on top of the plurality of light emitting diodes; a first planar portion connected to the first curved portion; and a second planar portion located; a second curved portion connected to the first planar portion; A light guide plate including a third curved portion connected to the second plane portion;
A first reflecting portion located on a first side surface of the plurality of light emitting diodes below the first flat portion of the light guide plate;
A second reflecting portion located on a second side surface of the plurality of light emitting diodes below the second flat portion of the light guide plate;
The lighting device, wherein the end portion of the first reflection portion and the end portion of the second reflection portion are convex portions with respect to the light emitting diodes and concave portions between the plurality of light emitting diodes. The lighting device according to claim 4, wherein a prism or a concave portion is formed on a lower surface of each of the first planar portion and the second planar portion. The one end portion on the upper surface of the first reflecting portion and the one end portion on the upper surface of the second reflecting portion are convex portions at the light emitting diodes and concave portions between the plurality of light emitting diodes. Item 6. The lighting device according to Item 4 or 5.

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