JP6452073B2 - LIGHT EMITTING DEVICE AND APPARATUS HAVING LIGHT EMITTING DEVICE - Google Patents

Description

  The present invention relates to a light emitting device suitable for lighting such as a signboard, a wall, and a road surface.

  Patent Document 1 describes providing an illumination device that can uniformly illuminate a display surface having a large area such as a large signboard with a plurality of illuminators. Therefore, in Patent Document 1, in a display panel illumination device including a plurality of illuminators (light projectors) for illuminating a display surface of a large signboard, at least one of the plurality of illuminators is the illuminator. By illuminating a wide area of the display surface close to, and configuring at least one other illuminator to illuminate a narrow area of the display surface far from the illuminator, by combining the illumination light of each illuminator, It is described that the illuminance of each illumination area can be made substantially uniform, and the illuminance uniformity of the boundary area of each illumination area can be increased.

JP 2003-195790 A

  It is required to illuminate areas to be illuminated such as signboards, walls, and roads so that the brightness is more uniform.

One aspect of the present invention is a light-emitting device having a light-emitting portion that projects light obliquely with respect to an illumination surface having a square illumination target area. The contour viewed from the light projecting direction of the light emitting part is a trapezoidal shape including a first side and a second side that is opposite to the first side and is longer than the first side. The plurality of light emitting elements is a region including a plurality of rows arranged in parallel to the first side and the second side between the first side and the second side, and the plurality of light emitting elements Is the same number of light emitting elements arranged in different densities for each column, the luminance per unit length for each column is different, than the first luminance per unit length of the first side The brightness changes so that the second brightness per unit length of the second side is lowered, and light is emitted when a trapezoidal light emitting unit projects a square or a near-square projected image onto the illumination surface. first the first projected image by the side of the brightness of the sides and the brightness of the second side of the projected image by the second side of the light emitting portion of the section is arranged so that the same extent Including the region.

  According to the present invention, it is possible to illuminate areas to be illuminated, such as signboards, walls, and roads, so that the brightness is more uniform.

The figure which shows the outline | summary of the illuminating device using the light-emitting device which concerns on 1st Embodiment. FIG. 2A is a diagram illustrating a light emitting surface of the light emitting device, and FIG. 2B is a diagram illustrating an illumination surface illuminated by the illumination device. FIGS. 3A and 3B are diagrams illustrating the light emitting device extracted from the lighting device, in which FIG. 3A is a view of the light emitting device viewed from the light emitting surface side, and FIG. 3B is a cross-sectional view taken along line bb of the light emitting device. The drawing substitute photograph which shows the illumination surface illuminated by the illuminating device. The figure which shows the illumination intensity distribution of the illumination surface illuminated by the illuminating device. It is a figure which shows the illumination intensity distribution on each axis | shaft of X axis | shaft orthogonal to the center of the illumination object area | region of an illumination surface, and a Y-axis, a solid line shows the illumination intensity on an X axis, and a broken line shows illumination intensity on a Y axis. It is a figure which shows the light-emitting device which concerns on 2nd Embodiment, Fig.7 (a) is the figure which looked at the light-emitting device from the light emission surface side, FIG.7 (b) is bb sectional drawing of a light-emitting device. It is a figure which shows the light-emitting device which concerns on 3rd Embodiment, FIG. 8 (a) is the figure which looked at the light-emitting device from the light emission surface side, FIG.8 (b) is bb sectional drawing of a light-emitting device. It is a figure which shows the light-emitting device which concerns on 4th Embodiment, Fig.9 (a) is the figure which looked at the light-emitting device from the light emission surface side, FIG.9 (b) is bb sectional drawing of a light-emitting device. The figure which shows the outline | summary of the illuminating device using the light-emitting device which concerns on 5th Embodiment. Fig.11 (a) is a figure which shows the light emission surface of a light-emitting device, FIG.11 (b) is a figure which shows the illumination surface illuminated by the illuminating device.

  In FIG. 1, the outline | summary of the illuminating device 1 using the light-emitting device 10a which concerns on 1st Embodiment is shown. FIG. 2A shows a light emitting surface 30a of the light emitting device 10a, and FIG. 2B shows an illumination surface 90 illuminated by the illumination device 1.

  The illumination device (projector) 1 includes a light emitting device 10a, a light projecting optical system 20 that projects light from the light emitting device 10a onto an illumination surface (irradiation surface) 90, and a control unit 80 that controls light emission of the light emitting device 10a. It has. In addition, in this specification, the illumination surface 90 means the surface where the light from the light emitting device 10a is irradiated.

  The example shown in FIG. 1 is a system 200 that uses the surface of a signboard placed at a high place as an illumination surface 90 and illuminates with the illuminating device 1, and the surface of the signboard (illumination) inclined obliquely toward the ground or road surface below. The illumination target region 92c on which the content of the surface 90 is drawn is illuminated by the illumination device 1 with the optical axis 21a oriented substantially in the horizontal direction.

  The light emitting device 10 a includes a substrate 40 and a light emitting unit 30 mounted on the substrate 40. The light emitting unit 30 has a thin plate shape as a whole, and includes a light emitting surface 30a having a trapezoidal outline 70 viewed from the light projecting direction 100 (the direction of the optical axis 21a). The direction of the optical axis 21a is not limited to the horizontal direction, and when the light emitting surface 30a having the trapezoidal shape 70 is used, the optical axis 21a may be inclined with respect to the illumination surface 90.

  The light emitting surface 30a may be a surface curved with respect to the light projecting direction 100, for example, a convex surface or a concave surface, and the contour 70 viewed from the light projecting direction 100 only needs to be trapezoidal. The shape of the contour 70 viewed from the light projecting direction 100 may change depending on conditions such as the shape of the illumination target region 92c and the angle of the optical axis 21a with respect to the illumination target region 92c, and may be a trapezoid whose sides are inclined. It may be a single trapezoid. In this example, the light emitting surface 30a is a flat surface, and the light emitting unit 30 as a whole has a thin trapezoidal columnar shape. The substrate 40 may be a printed wiring type or a lead frame type.

  The light projecting optical system 20 disposed in the emission direction of the light emitting device 10a includes a refractive optical system 21 including at least one lens (projection lens). The refractive optical system 21 inverts an isosceles trapezoidal image (light source image, first image surface) 91 of the light emitting surface 30a and enlarges and projects a projected image (second image surface) 92 on the illumination surface 90 ( Light). In the present specification, the emission direction refers to a direction in which light from the light emitting device 10a travels along the optical axis 21a.

  An example of the illumination surface 90 is a signboard surface, a sign surface, a road surface, a floor surface, a wall surface, a ceiling surface, a screen, and the like. The lighting device 1 can be used for signboard lighting, sign lighting, outdoor lighting (road lighting, street light), indoor lighting, lighting for projector devices, backlights for display devices, headlights for vehicles, and a relatively wide range. It can be used in a variety of applications, including other applications that illuminate.

  When the illumination device 1 is used as signboard illumination, it may be an external illumination type that illuminates the signboard surface 90 from the outside of the signboard, or an internal illumination type that houses the illumination device 1 inside the signboard. Further, depending on the illumination application, the side around the light emitting surface 30a may be a straight line, or may be a curved line having a substantially trapezoidal shape as a whole. The light projecting optical system 20 may include a refractive optical system 21 and / or a reflective optical system including at least one reflective surface.

  In FIG. 3, the light emitting device 10 a is extracted from the lighting device 1. 3A is a view of the light emitting device 10a viewed from the light emitting surface 30a side, and FIG. 3B is a cross-sectional view taken along the line bb of the light emitting device 10a (the bb cross section of FIG. 3A).

  The light emitting unit 30 includes a light emitting unit (light emitting body) 50 and a light diffusion unit that diffuses light from the light emitting unit 50. The light emitting unit 30 of this example is configured by combining (bonding) a thin plate-like light emitting unit 50 and a light diffusing unit having a common contour 70 viewed from the light projecting direction 100 in the light projecting direction 100.

  The light emitting unit 50 includes one light emitting element (LED) 51 and a packaging member 52 that covers the LED 51. In the light emitting unit 50 of this example, a blue LED is used as the LED 51, and white light is obtained by the blue LED 51 and the yellow phosphor 53 included in the packaging member 52.

  The light diffusion unit disposed on the side of the illumination surface 90 of the light emitting unit 50 is a thin plate (trapezoidal column) light diffusion member (diffusion plate or diffusion layer) 60 as a whole, and has a contour 70 viewed from the light projecting direction 100. Includes a trapezoidal first surface (surface) 60 a, and the first surface 60 a of the light diffusing member 60 substantially constitutes the light emitting surface 30 a of the light emitting unit 30.

  The contour 70 of the first surface 60a is non-parallel to the first side (upper base) 71 and the second side (lower base) 72 facing in parallel, and the upper base 71 and the lower base 72 are straight lines. The third side (leg) 73 and the fourth side (leg) 74 are connected to each other, and the lower base 72 is longer than the upper base 71 and has an isosceles trapezoidal shape.

  The first surface 60 a, that is, the light emitting surface 30 a is an isosceles trapezoidal plane when viewed from the emission direction, and is lower than the first luminance 71 b per unit length of the upper base (short side) 71. Side) 72 is provided with a region 75 in which the luminance (light emission intensity) changes so that the second luminance 72b per unit length of 72 is lowered. The region 75 in which the luminance changes is a gradation region having a luminance distribution (light emission intensity distribution) in which the luminance gradually changes from the short side 71 to the long side 72 of the light emitting surface 30a. Note that the gradation region 75 may have a luminance distribution in which the luminance continuously changes from the short side 71 to the long side 72 of the light emitting surface 30a, or may have a luminance distribution that changes continuously. .

  The first surface 60 a of the light diffusing member 60 is a plane that is inclined non-perpendicular to the emission direction of the LED 51, and emits light from the upper base (short side) 71 side toward the lower base (long side) 72 side. A first gradient 60b is provided so that the thickness of the light projecting direction (optical axis direction) 100 of the diffusing member 60 gradually increases. That is, the light diffusing member 60 has a diffusing performance in which light diffusibility gradually increases from the short side 71 toward the long side 72. For this reason, the luminance (light quantity) of the light emitting surface 30a decreases in proportion to the thickness of the light diffusion member 60. Therefore, it is possible to form a gradation region 75 in which the luminance gradually decreases (changes) from the short side 71 to the long side 72 of the light emitting surface 30a. In addition, the formation means of the gradation area | region 75 is not limited to this, You may form by changing the thickness of the light-diffusion member 60 like this example, and it is formed by changing the application quantity of a diffusing agent. Alternatively, it may be formed by other methods. When forming by changing the coating amount of the diffusing agent, the gradation region 75 can be formed by gradually increasing the coating amount of the diffusing agent from the short side 71 side to the long side 72 side of the light emitting surface 30a.

  In the illumination device 1, the light source image 91 on the light emitting surface 30 a is projected obliquely with respect to the illumination surface 90. Accordingly, the short side 71 is projected as the first side (end side) 92a of the projected image 92 at the first position p1 of the illumination surface 90 that is separated from the light emitting surface 30a by the distance d1, and the long side 72 is the light emitting surface. The light is projected as a second side 92b of the projected image 92 at a second position p2 of the illumination surface 90 that is separated from 30a by a distance d2 longer than the distance d1. For this reason, the light projection magnification of the short side 71 projected from the light emitting surface 30a at a long distance (far) is larger than the light projection magnification of the long side 72 projected from the light emitting surface 30a at a short distance (near). Get higher. Therefore, the amount of decrease in light intensity (light quantity) on the first side 92a of the projected image 92 (the amount of decrease in luminance relative to the luminance 71b on the short side 71) is the light intensity on the second side 92b of the projected image 92. It is larger than the amount of decrease (the amount of decrease in luminance with respect to the luminance 72b of the long side 72).

  Further, the light emitting surface 30a includes a gradation region 75 in which the luminance gradually decreases from the short side 71 side toward the long side 72 side. That is, in the light emitting device 10a, the relationship between the lengths of the two opposing sides 71 and 72 of the light emitting surface 30a and the luminance per unit length of each side is reversed, and the opposing two sides 71 and 72 are separated by the gradation region 75. Connected. Therefore, the high-luminance short side 71 side is set higher than the low-luminance long side 72 side by utilizing the difference in distance between the illumination surface 90 and the light-emitting surface 30a inclined with respect to the optical axis 21a of the light-emitting device 10a. By projecting at a magnification, the amount of decrease in luminance (light quantity) can be gradually reduced from the first side 92a side to the second side 92b side of the projected image 92. For this reason, it is easy to make the brightness (illuminance, irradiation intensity) of the area (illumination target area) 92c where the gradation area 75 is projected onto the illumination surface 90 uniform. Accordingly, the brightness and length per unit length of each of the short side 71 and the long side 72, and the projection magnification so that the brightness of the first side 92a and the brightness of the second side 92b are approximately the same. By changing the above, it is possible to project a square or nearly square projected image 92 with uniform brightness. For this reason, in the light emitting device 10a, the energy efficiency required for the illumination with respect to the square illumination object area | region 92c is high, and the highly efficient illuminating device 1 with low power consumption can be provided.

  As described above, in the lighting device 1, the length of the short side 71 and the long side 72, the luminance per unit length, and the projection distance are controlled to match the desired shape, for example, the shape of the rectangular signboard surface 90. The illumination target area 92c can be illuminated with light of uniform brightness without unevenness. Further, it is possible to provide the lighting device 1 that can suppress the light from the light emitting surface 30a from leaking to the outside of the signboard surface 90, and can suppress the occurrence of so-called light damage due to unnecessary light while saving power. Furthermore, the refractive optical system 21 only needs to be designed to the extent that the light source image 91 can be projected as the projected image 92. By controlling the shape and the projection distance of the light emitting unit 30 on the light emitting device side, The trouble of redoing the design can be omitted or reduced.

  In FIG. 4, the state of the illumination surface 90 illuminated by the illuminating device 1 is shown by a photograph substituted for a drawing. FIG. 5 shows the illuminance distribution on the illumination surface 90. FIG. 6 shows the illuminance distribution on each axis of the X axis and the Y axis orthogonal to each other at the center 99 of the illumination target area 92 c of the illumination surface 90. In FIG. 6, the solid line indicates the illuminance on the X axis, and the broken line indicates the illuminance on the Y axis.

  In FIG. 5, reference numeral 101 indicates 100 to 200 lux, reference numeral 102 indicates 200 to 300 lux, reference numeral 103 indicates 300 to 400 lux, reference numeral 104 indicates 400 to 500 lux, and reference numeral 105 indicates 500 to 600. Reference numeral 106 indicates 600-700 lux, reference numeral 107 indicates 700-800 lux, reference numeral 108 indicates 800-900 lux, reference numeral 109 indicates 900-1000 lux, reference numeral 110 indicates 1000-1100. The reference numeral 111 indicates 1100 to 1200 lux. In FIG. 6, the solid line indicates the on-axis illuminance on the X axis, and the broken line indicates the on-axis illuminance on the Y axis.

  As shown in FIGS. 4 to 6, in the illumination device 1, a rectangular projection image 92 is irradiated onto the illumination surface 90. In the case of an illuminating device, the focus is generally not adjusted so accurately, and a portion where the illuminance is stable excluding the peripheral portion of the projected image 92 is defined as an imaging region (illumination target surface, illumination target region) 92c. The variation in illuminance in the region 92c is suppressed to about 20%, and the rectangular irradiation range can be illuminated with light having substantially uniform brightness.

  In the conventional beam lamp type LED lamp, for example, “LightingTips“ design point of signboard lighting ”issued by Toshiba Lighting & Technology Co., Ltd., (d) an arrangement example (lighting from above) with a beam lamp type LED lamp, p. In “4”, the illuminance with respect to the irradiation range allows about 800 lux to 100 lux. That is, an illuminance fluctuation of 800% is allowed. On the other hand, as described above, in the light emitting device 10a of this example, it is possible to select a region 92c of 800 lux or more of the rectangular projection image 92 as an illumination target region, and 1000 lux or more of the inside is selected. Although the portion is included, the rectangular illumination target surface 92c can be illuminated with an illuminance fluctuation of about 20 to 30%.

  In the illuminating device 1 of this example, the vertically long trapezoidal light emitting surface 30a having the legs 73 and / or legs 74 that are longer than the upper base 71 and / or the lower base 72, the Y-axis direction is longer than the X-axis direction. The rectangular illumination target region 92c is illuminated, but the X-axis with respect to the Y-axis direction is formed by the horizontally elongated trapezoidal light-emitting surface having a long upper base 71 and / or lower bottom 72 with respect to the legs 73 and / or legs 74. It is also possible to illuminate a horizontal rectangular illumination target region having a long direction.

  FIG. 7 shows a light emitting device 10b according to the second embodiment. 7A is a view of the light emitting device 10b as viewed from the light emitting surface 30a side, and FIG. 7B is a cross-sectional view taken along the line bb of the light emitting device 10b (the bb cross section of FIG. 7A). In addition, in Fig.7 (a), the LED mounting surface of the light-emitting device 10b is shown. The same applies to FIG. 8A and FIG. 9A. In the following embodiments, the same components as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted.

  The light emitting unit 30 of the light emitting device 10b includes a light emitting unit 50 and a light diffusing member 60 that share a trapezoidal outline 70 viewed from the light projecting direction 100. Similar to the light emitting device 10a described above, the outline 70 viewed from the emission direction may be trapezoidal, and the light emitting surface 30a itself may be curved.

  The light emitting unit 50 includes a plurality of LEDs 51, a packaging member 52 that covers the plurality of LEDs 51, and a plurality of LEDs 51 that are divided into a plurality of rows (columns) along the short side 71 and the long side 72 of the light emitting surface 30a. And an array region 55.

  The array area 55 includes four rows (four rows) of LED rows 55 a to 55 d arranged between the short side 71 and the long side 72. Each of the LED rows 55a to 55d is composed of seven LEDs 51 arranged in a staggered manner in the row direction. In each LED row 55a to 55d, the same number of LEDs 51 are arranged at different densities, and the LEDs 51 are arranged so that the arrangement density of the LEDs 51 increases from the long side 72 side toward the short side 71 side. The substrate 40 on which the plurality of LEDs 51 are mounted includes a wiring pattern (circuit) 45 that can connect the plurality of LEDs 51 in each stage of the LED rows 55a to 55d in parallel.

  The control unit 80 includes general-purpose hardware resources as a computer such as a CPU and a memory, and has various functions for controlling the light emission of the light emitting device 10b by a program (program product) stored in a memory such as a RAM. Each function of the control unit 80 described below is implemented in the control unit 80 by a program or an appropriate circuit. The control unit 80 may be mounted on the substrate 40.

  The control unit 80 includes a first unit 81 that controls the drive current for each of the LED rows 55a to 55d in the arrangement region 55. The first unit 81 includes a first function 81a that applies a constant drive current to the LEDs 51 connected in parallel in each stage of the LED rows 55a to 55d. Therefore, each LED 51 emits light with the same luminance.

  In the light emitting device 10b, the LEDs 51 arranged so that the arrangement density gradually decreases from the LED row 55a on the short side 71 side toward the LED row 55d on the long side 72 side emit light having the same luminance (light emission intensity). Emits light. Therefore, the luminance per unit length on the upper stage side (short side 71 side) of the arrangement region 55 can be made higher than the luminance per unit length on the lower stage side (long side 72 side), and the light emitting surface 30a. A gradation region 75 in which the luminance gradually decreases from the short side 71 side toward the long side 72 side can be formed.

  In the light emitting device 10b, the light diffusing member 60 arranged in the emission direction of the light emitting unit 50 suppresses (relaxes) the graininess and luminance unevenness of each LED 51. Further, the gradation area 75 of the light emitting surface 30a is realized by the number and arrangement density of the LEDs 51 in each stage of the arrangement area 55. Therefore, the first gradient 60b may be provided on the first surface 60a of the light diffusing member 60, but the gradation region 75 can be realized without providing the gradient 60b. Accordingly, the light emitting device 10b may include the light diffusing member 60 having a substantially constant thickness in the light projecting direction 100 from the short side 71 side to the long side 72 side. Cheap.

  FIG. 8 shows a light emitting device 10c according to the third embodiment. 8A is a view of the light emitting device 10d viewed from the light emitting surface 30a side, and FIG. 8B is a cross-sectional view taken along the line bb of the light emitting device 10d (the bb cross section of FIG. 8A).

  The array region 55 of the light emitting unit 50 includes four rows (four rows) of LED rows 55 a to 55 d disposed between the short side 71 and the long side 72. In each of the LED rows 55a to 55d, a plurality of LEDs 51 are arranged in a staggered manner in the row direction, and the LED rows 55a and 55b each have seven pieces in order from the short side 71 side to the long side 72 side. The LED rows 55c and 55d are each composed of 13 LEDs 51.

  The first unit 81 of the control unit 80 includes a second function 81b that applies a larger driving current to the LED 51 on the upper stage side (LED row 55a side) than the lower stage side (LED row 55d side). . Therefore, the luminance per unit length on the upper side of the arrangement region 55 can be made higher than the luminance per unit length on the lower side, and further, from the short side 71 side to the long side 72 side of the light emitting surface 30a. A gradation region 75 where the luminance gradually decreases can be formed.

  In the light emitting device 10c, the LED 51 is arranged so that the arrangement density of the LEDs 51 increases from the long side 72 toward the short side 71 as in the light emitting device 10b, but the long side 72 from the short side 71 side is arranged. The number of LEDs 51 is gradually increased toward this side. For this reason, the arrangement density of the LEDs 51 on the lower side of the arrangement region 55 can be made higher than that of the light emitting device 10b. Therefore, it is easy to further suppress the luminance unevenness of each LED 51, and the light diffusion member 60 can be made thinner than the light emitting device 10b.

  FIG. 9 shows a light emitting device 10d according to the fourth embodiment. 9A is a view of the light emitting device 10d as seen from the light emitting surface 30a side, and FIG. 9B is a cross-sectional view taken along the line bb of the light emitting device 10d (the bb cross section of FIG. 9A).

  The array region 55 of the light emitting unit 50 includes eight rows (eight rows) of LED rows 55 a to 55 h arranged between the short side 71 and the long side 72. In each of the LED rows 55a to 55h, a plurality of LEDs 51 are linearly arranged in the row direction, the uppermost LED row 55a is composed of eight LEDs 51, and the lowermost LED row 55h is 15 LEDs 51. Each stage LED 51 increases by one as it goes from the upper stage side to the lower stage side. Therefore, the second function 81b of the control unit 80 that applies a larger driving current to the upper LED 51 than the lower LED side gradually increases the luminance from the short side 71 side to the long side 72 side of the light emitting surface 30a. A gradation region 75 that decreases as a result can be formed.

  In each of the LED rows 55a to 55h, the LEDs 51 of each stage are arranged at substantially equal intervals, and the arrangement density of the LEDs 51 does not change substantially from the long side 72 side toward the short side 71 side. That is, in the light emitting device 10d, the plurality of LEDs 51 at each stage of the arrangement region 55 are densely arranged at equal pitches without leaving a gap between adjacent LEDs 51 or with a very narrow gap. For this reason, there is no variation in element spacing for each stage of the array region 55, the luminance unevenness of the light emitting surface 30a is suppressed, and a gradation region 75 in which the luminance change is continuous and smoother can be formed. Therefore, the light-emitting device 10d in which the light diffusing member 60 is omitted or the light diffusing member 60 is extremely thin can be provided.

  In FIG. 10, the outline | summary of the illuminating device 1 using the light-emitting device 10e which concerns on 5th Embodiment is shown. FIG. 11A shows the light emitting surface 30a of the light emitting device 10e, and FIG. 11B shows the illumination surface 90 illuminated by the illumination device 1.

  The example shown in FIG. 10 is a system 300 that illuminates a lighting surface 90 such as a floor surface or a road surface vertically below (directly below) with a lighting device 1 arranged at a high place such as a ceiling or a streetlight. The optical axis 21 a is arranged perpendicular to the illumination surface 90. The wall surface can be used as the illumination surface 90, and the optical axis 21a of the illumination device 1 can be arranged perpendicular to the wall surface.

  The light emitting unit 30 of the light emitting device 10e has a thin plate shape as a whole, and includes a light emitting surface 30b having a hexagonal shape when viewed from the light projecting direction 100. The light emitting surface 30b includes a first light emitting surface 30a and a second light emitting surface 30a each having a trapezoidal shape 70 when viewed from the light projecting direction 100, and a long side (second side) 72 of each light emitting surface 30a. Are formed so as to be in the center (connection side).

  The light emitting surface 30b is a hexagonal plane when viewed from the emission direction, and the first short side 73a of the first light emitting surface 30a and the second short side 73b of the second light emitting surface 30b are opposed in parallel. doing. Therefore, the light emitting surface 30b includes the first gradation region 75a in which the luminance gradually decreases (decreases) from the first short side 73a toward the common long side 72, and the common long side 72 to the second short side. And a second gradation region 75b in which the luminance gradually increases (rises) toward the side 73b. Similar to the light emitting device described above, the light emitting surface 30b itself may be curved.

  In the illuminating device 1, the light source image 91 of the light emitting surface 30a is enlarged and projected in parallel to the illumination surface 90, that is, from the front. For this reason, the light projection magnification of the first short side 73a and the second short side 73b projected far from the light emitting surface 30a is the long side 72 projected from the light emitting surface 30a to the near side (vertically below). Higher than the light projection magnification. Therefore, by projecting the opposing high-luminance short sides 73a and 73b on the low-luminance long side 72 side at a high magnification, the upper and lower, left-right, or front-and-rear end edges 99a of the projected image 92 are projected. The amount of decrease in luminance (light quantity) can be gradually decreased from 99b toward the center 99. For this reason, it is easy to make the brightness (illuminance) of the illumination target area 92c where the gradation areas 75a and 75b are projected onto the illumination surface 90 uniform. Therefore, the illumination device 1 having the outgoing optical axis (optical axis 21a) perpendicular to the illumination surface 90 can illuminate the rectangular illumination target region 92c with uniform brightness.

  In addition, this invention is not limited to these embodiment, What was prescribed | regulated by the claim is included. For example, the short side 71 and / or the long side 72 of the light emitting surface 30a may face each other non-parallelly or may be a curved line. Further, the light emitting surface 30a and / or the illumination surface 90 may be a curved surface as well as a flat surface.

  In recent years, lighting using LEDs (light-emitting diodes) has reduced the illuminance comparable to that of light sources such as halogen bulbs, mercury lamps, and fluorescent lamps due to high directivity of light, ease of brightness control, and improvement of luminous efficiency. Realized by electric power, these conventional light sources are being replaced and newly established in various fields. However, lighting fixtures (lamps) using LEDs that are currently being studied remain in the same shape as lamps using conventional light sources. In other words, the design that does not give the user a sense of incongruity with the replacement of conventional lamps is the mainstream, and it cannot be said that the lighting performance has been fully utilized yet, and the light source shape that was difficult to realize with conventional light sources And a novel illumination device using the shape of the light source is not found.

  On the other hand, outdoor lighting at night illuminates parts other than the target, and problems such as visibility in traffic, influence on animals and plants, especially crops, and obstacles to astronomical observation are recognized as so-called light pollution. An LED that has high directivity and can be easily controlled by optical components is considered to be a suitable light source in that it suppresses light irradiation to a non-target part that causes light damage.

  When a conventional light source is used, the irradiation range is elliptical, and thus a plurality of projectors are arranged so that the illuminance on the sign is uniform. For this reason, illuminance non-uniformity occurs in the portion where the light beams of adjacent projectors overlap, and the illuminance decreases as the distance from the projector increases. In order to reduce such illuminance non-uniformity, it is conceivable to use only the portion in the vicinity of the center of the irradiation range of each projector. In that case, the light outside the center is moved outside the signboard surface. Leakage increases unnecessary light and power consumption also increases.

  In the present invention, a trapezoidal light source (light emitting device) in which the contour 70 of the light emitting unit 30 is trapezoidal is used, and the lengths of the two opposite sides 71 and 72 of the trapezoidal light emitting surface 30a and the unit length of each side are used. By reversing the relationship with the brightness per unit, a gradation region 75 in which the luminance gradually decreases from the short side 71 toward the long side 72 is formed on the light emitting surface 30a. For this reason, the illuminating device 1 which can illuminate the desired shape, for example, the irradiation range of a square shape congruent with the shape of a signboard surface with the light of uniform brightness can be provided. Therefore, the light (stray light) leaking from the signboard surface to the outside can be reduced, the occurrence of light pollution can be suppressed, and the power saving lighting device 1 can be provided. The light source is not limited to the LED, but may be an OLED (organic EL) or a combination of an LED, an OLED and / or other light source and a light diffusion unit.

DESCRIPTION OF SYMBOLS 1 Illuminating device 10a, 10b, 10c, 10d, 10e Light-emitting device 20 Light projection optical system

Claims (8)

A light-emitting device having a light-emitting portion that projects obliquely with respect to an illumination surface having a square illumination target area,
The contour viewed from the light projecting direction of the light emitting unit is a trapezoid including a first side and a second side that is opposite to the first side and is longer than the first side,
The light emitting unit includes a plurality of rows in which a plurality of light emitting elements are arranged in parallel to the first side and the second side between the first side and the second side. The plurality of light emitting elements in the plurality of columns are arranged in the same number of light emitting elements at different densities, the luminance per unit length of each column is different, and the first The luminance changes such that the second luminance per unit length of the second side is lower than the first luminance per unit length of the side, and the illumination surface is caused by the trapezoidal light emitting unit. Furthermore, when a square or a projection image close to a square is projected, the brightness of the first side of the projection image by the first side of the light emitting unit and the projection image by the second side of the light emitting unit A light-emitting device including a region arranged so that the brightness of the second side of the light source is approximately the same. In claim 1,
The arranged region includes a row in which the same number of light emitting elements are arranged in a staggered manner. A light-emitting device having a light-emitting portion that projects obliquely with respect to an illumination surface having a square illumination target area,
The contour viewed from the light projecting direction of the light emitting unit is a trapezoid including a first side and a second side that is opposite to the first side and is longer than the first side,
The light emitting unit includes a plurality of rows in which a plurality of light emitting elements are arranged in parallel to the first side and the second side between the first side and the second side. Including regions, and
The plurality of columns each include a control unit that controls a drive current for each column, wherein the plurality of light emitting elements have different luminance per unit length for each column, and the light emitting unit includes the first side The luminance changes so that the second luminance per unit length of the second side is lower than the first luminance per unit length of When a square or a projection image close to a square is projected, the brightness of the first side of the projection image by the first side of the light emitting unit and the first number of the projection image by the second side of the light emitting unit. A light emitting device including a region arranged so that the brightness of the two sides is approximately the same. In any of claims 1 to 3 ,
The light emitting unit is a light emitting device including a light diffusing member. In claim 4 ,
The said light-diffusion member is a light-emitting device containing the diffusion performance from which a light diffusivity becomes high toward the said 2nd edge | side from the said 1st edge | side. In any of claims 1 to 5 ,
The light emitting device includes a substrate on which the light emitting unit is mounted, and the substrate includes a wiring pattern that connects the plurality of light emitting elements for each of the columns . In any one of Claims 1 thru | or 6.
A light emitting device having a plurality of the light emitting portions arranged so that the second side is the center. A light emitting device according to any one of claims 1 to 7,
A light projecting optical system that projects light from the light emitting unit;