JP7149481B2 - Lighting device and light emitting unit - Google Patents

Description

The present invention relates to a lighting device and a light emitting unit using a semiconductor light source.

A light-emitting device or lighting device using a laser diode (LD) as a light source has been developed. When using a highly directional laser beam light (hereinafter referred to as beam light) as a light source for illumination, instead of using the highly directional beam light as it is, it is irradiated to a wavelength conversion member (phosphor), and the wavelength is converted into diffusion. It is devised so that it can illuminate a wide range by converting it into light.

Patent Literature 1 describes providing a light-emitting device capable of efficiently emitting mixed light using wavelength-converted light from phosphors. This light emitting device has a light source capable of emitting emission light, a first phosphor layer, and a light guide path. The first phosphor layer includes at least a first surface and a second surface opposite to the first surface, extends in a light guiding direction, absorbs the emitted light, and dissipates the emitted light. A first wavelength-converted light having a longer wavelength is enabled to be emitted. The light guide path has a reflector, an incident surface of the emitted light, a reflective surface provided on the surface of the reflector and in contact with the first surface of the first phosphor layer, and the an exit surface spaced apart from the first phosphor layer. Moreover, the reflecting surface and the emitting surface extend in the light guiding direction.

Patent Literature 2 describes providing an edge-light type lighting fixture capable of emitting light also from the side of the light guide plate. A lighting fixture has a light source that emits light forward, a first main surface, a light guide plate that guides light emitted by the light source toward the first main surface, and a main body that faces the first main surface. and a peripheral portion that surrounds at least a portion of the side surface of the light guide plate. The reflective part is arranged between the peripheral edge of the cover and the side surface of the light guide plate so as to emit light, and the reflective part reflects the light emitted by the light source toward the rear of the light source.

JP 2012-099362 A JP 2015-130271 A

An object of the present invention is to provide a lighting device having a simple structure and high light utilization efficiency.

An aspect of an embodiment of the present invention is a semiconductor light source, and a first optical system for collimating a component of a first light beam output from the semiconductor light source in either the horizontal direction of the radiation angle or the vertical direction of the radiation angle into parallel light. The illumination device includes an optical system including an element, and a light emitting unit including a wavelength conversion surface for outputting wavelength-converted light irradiated by a second light beam output from the optical system. The wavelength conversion surface extends along a first contour shape along the first surface including either the horizontal direction of radiation angle or the vertical direction of radiation angle, and the first contour shape extends along the second luminous flux. At least part of the first contour shape satisfies the following formula (1) in XY coordinates showing the first plane with the semiconductor light source as the origin and the optical axis as the X axis do.
(x2-x1) ² + (y2-y1) ² = (αg(θ+dθ/2)) ² (1)
however,
y1=x1·tan(θ+dθ)
y2=x2·tan θ
g(θ)=exp(−θ ² /(2×σ ² ))
is the angle from the X axis, α is the constant of proportionality, and σ2 is the value indicating the dispersion of the component in the other direction of the ^second light flux.

The first contour shape may include a shape corrected for the contribution of the reflection component of the second light beam on the wavelength conversion surface, and may be represented by Equation (2).
(x2-x1) ² + (y2-y1) ² = (α·g(θ+dθ/2)·h(θ)) ²
... (2)
However, the function h(θ) is a function that corrects at least the contribution of the reflection component of the second light beam on the wavelength conversion surface.

Also, the first contour shape may be symmetrical with respect to the optical axis of the second light beam, and may be a boat shape with the semiconductor light source side of the optical axis as the stern and the opposite side as the bow.

Furthermore, the first contour shape is formed by the second light beam and the light reflected by the other unit light emitting portion for the unit light emitting portion divided by the unit angle from the optical axis with the semiconductor light source as the origin. , a shape in which the irradiation dose is substantially equal to that of the first contour shape.

In one aspect of the embodiment of the present invention, the component of either the horizontal direction of the radiation angle or the vertical direction of the radiation angle of the first light flux output from the semiconductor light source is irradiated by the second light flux collimated into parallel light. , a light-emitting unit including a wavelength conversion surface for outputting wavelength-converted light, wherein the wavelength conversion surface is along a first surface including the other of the horizontal direction of radiation angle and the vertical direction of radiation angle. the first contour shape is symmetrical with respect to the optical axis of the second light flux, and at least part of the first contour shape extends along the semiconductor light source. A light-emitting unit that satisfies the following conditions in terms of XY coordinates showing the first plane with the optical axis as the X-axis, with the origin as the X-axis.
(x2-x1) ² + (y2-y1) ² = (αg(θ+dθ/2)) ²
y1=x1·tan(θ+dθ)
y2=x2·tan θ
g(θ)=exp(−θ ² /(2×σ ² ))
is the angle from the X-axis, α is the constant of proportionality, and σ2 is the value indicating the dispersion of the component of the ^second light flux in the other direction.

The lighting device according to the embodiment of the present invention can provide a simple structure and high light utilization efficiency.

1 is a perspective view showing an example of a lighting device; FIG. The figure which expand|deploys and shows an illuminating device. The top view of an illuminating device. Sectional drawing of a direction perpendicular|vertical to the optical axis of an illuminating device. Sectional drawing of the direction parallel to the optical axis of an illuminating device. 4A and 4B are diagrams for explaining an optical system of a lighting device; FIG. 4 is a diagram showing an example of a light-emitting unit of a lighting device; The figure which shows an example of the intensity distribution of the light beam input into a light emission unit. FIG. 4 is a diagram showing an example of drawing a contour shape for setting a wavelength conversion surface of a light emitting unit; The figure which shows the data which show a contour shape. The figure which shows an example which drew the contour shape. FIG. 4 is a diagram showing an expression for obtaining a calculated value of contour shape; The figure which shows the contour shape calculated|required by calculation. FIG. 4 is a diagram showing contour shapes corresponding to light beams with different radiation angles; The figure which shows the measured value of light emission surface intensity ratio. FIG. 4 is a diagram showing a function for correction based on the light emitting surface intensity ratio; FIG. 10 is a diagram showing another example of a lighting device; Sectional drawing of the direction perpendicular|vertical to an optical axis which shows another different example of an illuminating device. The figure which shows the other different example of an illuminating device.

FIG. 1 shows an example of a lighting device. The illumination device 1 is elongated and boat-shaped as a whole, and includes an optical unit 10 arranged on the stern side 2 and a pointed bow side (tip side) 3 on the side opposite to the stern side 2. It includes boat-shaped light emitting units 20 and a frame 9 that supports them.

FIG. 2 shows the illumination device 1 with the cover 11 of the optical unit 10 and the diffusion member 21 of the light emitting unit 20 removed. FIG. 3 shows a top view (plan view) of the illumination device 1, FIG. 4 shows a section (section IV-IV) perpendicular to the optical axis of the illumination device 1, and FIG. A cross section (cross section VV) parallel to the optical axis of the illumination device 1 is shown.

Optical unit 10 includes optics 19 that shape the source light. The optical system 19 includes a semiconductor light source 12 that outputs a light beam, and a first optical system that collimates the radiation angle of a first light beam 13 output from the semiconductor light source 12 and supplies it as a second light beam 14 to the light emitting unit 20 . element 15. An example of the first optical element 15 is a cylindrical lens 15a that collimates the radiation angle horizontal direction θp component of the first light flux 13, which is the light beam output from the semiconductor light source 12, into parallel light.

The light emitting unit 20 includes a side wall 25 whose inner surface 25 a forms a first contour shape (boat-shaped contour shape) 22 , a wavelength conversion surface 23 provided on the inner surface 25 a , and an emission surface 26 surrounded by the side wall 25 . , and a diffusing member 21 covering the exit surface 26 . The wavelength conversion surface 23 is a mirror surface or a diffusive reflection surface, and is a surface provided with a phosphor 23a for wavelength conversion by application or coating. When the wavelength-converting surface 23 is illuminated by the collimated second beam 14, the light 32 wavelength-converted by the phosphor 23a (fluorescent light, eg, yellow light) and the second beam 14 are supplied as Mixed light (white light) 33 that is wavelength-converted from blue, including reflected light (blue light) 31 that is a part of the beam light, is generated, passes through the diffusion member 21 that covers the emission surface 26 , and becomes illumination light 35 . is output as In the light-emitting unit 20 of this example, the inner surface 25 a of the side wall 25 and the inner surface (bottom surface) 29 of the frame 9 surrounded by the side wall 25 are mirror surfaces or diffuse reflection surfaces, and the mixed light generated by the wavelength conversion surface 23 is 33 is reflected in the direction of the exit surface 26 and output as illumination light 35 .

In these figures, the wavelength conversion surface 23 provided with the phosphor 23a is set wide, but the wavelength conversion surface 23 is within the inner surface 25a of the side wall 25, and the collimated beam light (second luminous flux) 14 may be irradiated. The inner surface 25a of the side wall 25 need not be a vertical wall and may be angled, and the inner surface 25a may be curved. A sheet having a high diffuse reflectance may be attached to the inner surface 25a of the side wall 25 other than the wavelength conversion surface 23 and the inner surface other than the diffusion member 21 including the bottom surface 29, or may be painted.

The diffusion member 21 may be made of a diffusing and translucent material. Specific materials for the diffusion member 21 include a semi-milk acrylic plate, white polyethylene, resin such as white ABS, and white glass. The shape of the diffusion member 21 may be a flat surface, a curved surface, or a shape including an arc.

An inner surface 25a of the side wall 25 provided with the wavelength conversion surface 23 forms a boat-shaped contour 22 . The first contour shape (boat-shaped contour shape) 22 is defined by one component of the radiation angle horizontal direction θp and the radiation angle vertical direction θv of the light beam (first light flux) 13 output from the semiconductor light source 12. A direction other than the direction collimated by the optical system 19, that is, in this example, extends along the first plane Sv including the direction of the radiation angle vertical direction θv, and collimated along the optical axis 14a of the second light beam 14. The stern side 2 is on the semiconductor light source 12 side of the optical axis 14a, and the bow side (tip side) 3 is on the opposite side (boat shape, curved line).

As shown in FIG. 6A, the radiation intensity of the light beam (first light flux) 13 output from the semiconductor light source 12 approximates a Gaussian distribution. The radiation angle of the FFP (Far Field Pattern) of the light beam is generally the angle at which the beam intensity in the horizontal direction θp and the vertical direction θv of the radiation angle is (1/e ² ). expressed. In general, the horizontal radiation angle .theta.p and the vertical radiation angle .theta.v of the light beam (first light flux) 13 are smaller in the horizontal radiation angle .theta.p and larger in the radiation angle .theta.v.

In the optical system 19 of the illumination device 1 , the radiation angle of either the horizontal radiation angle θp or the radiation angle vertical direction θv is shaped into parallel light by a collimating lens and output as the second light flux 14 . Then, by linearly irradiating the wavelength conversion surface 23 of the light emitting unit 20 with the shaped parallel second light flux 14, the illumination device 1 that can be used as the diffused illumination light 35 is provided. For example, even if the radiation angle in the horizontal direction .theta.p is collimated by the cylindrical lens 15a, the radiation angle in the vertical direction .theta.v (hereinafter referred to as the radiation angle .theta.) does not change. Since the intensity distribution of the light beam (first light beam) 13 output from the semiconductor light source 12 is approximated by a Gaussian function, hereinafter, the light beam (second light beam) with respect to the radiation angle θ in the vertical direction of the radiation angle θv A Gaussian functional expression representing the intensity distribution of 14 is determined, and a light emitting unit 20 is provided having a first profile 22 that provides a radiation length for equal radiant intensity based on the Gaussian functional expression.

As shown in FIGS. 6(b) and 6(c), in the optical system 19 of the illumination device 1 of this embodiment, the horizontal direction θp of radiation angle with a small radiation angle is shaped into parallel light by the cylindrical lens 15a, and the phosphor 23a is included. Illumination light 35 is obtained by irradiating the wavelength conversion surface 23 . In the illumination device 1 including the elongated light emitting unit 20 such as a fluorescent lamp, for example, the vertical direction θv having a large radiation angle may be collimated to obtain the second light flux 14 having a small radiation angle. .

As shown in FIG. 6(d), the optical system 19 may include other optical elements such as a mirror 15e or a prism as the optical element 15. FIG. Also, as shown in FIG. 6(e), the optical system 19 may include two or more cylindrical lenses 15a and 15b as the optical element 15. FIG. For example, the cylindrical lens 15a controls the radiation angle in the horizontal direction θp for parallelization, and the cylindrical lens 15b controls the radiation angle in the vertical direction θv to control the radiation angle θ of the second light flux 14 input to the light emitting unit 20. may be controlled to be an appropriate angle. Also, a toroidal lens (toric lens) capable of changing the vertical radiation angle and the horizontal radiation angle at the same time may be used. In addition, in these drawings, the laser diode (LD), which is the semiconductor light source 12, is shown as a can type (CAN type), but the present invention is not limited to this. Also, the number of laser diodes used as the semiconductor light source 12 is not limited to one. Further, as described above, hereinafter, the radiation angle of the non-collimated direction of the second light flux 14 input to the light emitting unit 20, in this example, the angle of the radiation angle vertical direction θv will be referred to as the radiation angle θ. .

FIG. 7 shows an illumination device 1 having a wavelength conversion surface 23 arranged along a first contour shape (boat-shaped contour shape) 22 . FIG. 7A shows an example of a shape that is uniquely determined by the Gaussian distribution function of the beam intensity of the luminous flux obtained from the semiconductor light source (LD) 12. FIG. This contour shape (first contour shape) 22 may be different for semiconductor light sources (LD) 12 having different radiation angles θ.

FIG. 7B shows the illumination device 1 including the wavelength conversion surface 23 arranged along the contour shape 22 corrected for the contribution of the reflection component on the wavelength conversion surface 23 . The contour shape 22 shown in FIG. 7A is a shape in which the second light beam 14 obtained from the semiconductor light source (LD) 12 through the optical system 19 is wavelength-converted with equal intensity and irradiated with the illumination light 35. However, the second light beam 14 is not wavelength-converted, and there is also a reflected portion of the second light beam 14 . That is, part of the second light flux 14 reflected by the wavelength conversion surface 23 hits the wavelength conversion surface 23 on the bow side (tip side) 3 and emits light. Furthermore, the closer the bow side 3 is, the closer the wavelength conversion surfaces 23 sandwiching the optical axis 14a are to each other. Therefore, in the illumination device 1 shown in FIG. 7B, the high brightness of the bow side 3 of the light emitting unit 20 is corrected so that the illumination light 35 can be output with more uniform emission brightness.

A method for creating the contour shape 22 for iso-intensity wavelength conversion of the second light beam 14 obtained by collimating the first light beam 13 from the semiconductor light source (LD) 12 will be described below. First, the Gaussian function of the second beam 14 collimated by the cylindrical lens 15a employed in the optical system 19 is obtained with one of the beam radiation angles, in this example, the radiation angle horizontal direction θp. Gaussian function g(θ) is generally represented by the following equation (3).
g(θ)=exp(−θ ² /(2×σ ² )) (3)
is the angle from the X axis when the optical axis 14a of the second light flux (light beam) 14 is the X axis, and σ2 is the dispersion of the component of the ^second light flux 14 in the vertical direction θv of the radiation angle. is the value shown.

FIG. 8 shows the optical output of the second beam 14 collimated by the cylindrical lens 15a employed in the optical system 19 of this example. The radiation angle of the semiconductor light source (LD) 12 in the horizontal direction θp (beam intensity 1/e ² ) is 8.4 degrees, and the radiation angle in the vertical direction θv (beam intensity 1/e ² ) is 45 degrees. After shaping by the lens 15a, the radiation angle (beam intensity 1/e ² ) in the horizontal direction θp is 0 degrees, the radiation angle (beam intensity 1/e ² ) in the vertical direction θv is 45 degrees, and the dispersion σ The standard deviation σ for ² was 11.8. When it is desired to adjust the radiation angle (beam intensity 1/e ² ) in the radiation angle vertical direction θv, it can be adjusted by arranging the cylindrical lenses 15a and 15b so as to cross the optical axis as shown in FIG. 6(e).

The radiation intensity of the second light beam 14 obtained from the semiconductor light source (LD) 12 through the optical system 19 is the strongest when the radiation angle θ is 0 degrees (on the optical axis 14a or on the X-axis), and the radiation angle θ becomes large. The radiant intensity decreases accordingly. Therefore, in order to make the irradiation intensity of the second light flux 14 to the wavelength conversion surface 23 constant, a method of correcting the radiation intensity difference by the radiation length with respect to the wavelength conversion surface 23 can be adopted. For example, assuming that the optical output on the optical axis is 1 from the irradiation intensity shown in FIG. 8, the intensity at a radiation angle of 20 degrees can be read as 0.24. Therefore, if the length of the wavelength conversion surface 23 at 0 degrees (around 0 degrees) is 4.2 times the radiation length (length of the wavelength conversion surface 23) at the radiation angle of 20 degrees, the wavelength conversion surface 23 The beam intensity per unit length (irradiation intensity of the second beam 14) is constant, and the emission intensity of the mixed light 33 containing the wavelength-converted light 32 per unit length is also constant. Since the radiant intensity of the second light beam 14 is symmetrical on the positive side and the negative side with respect to the radiation angle of 0 degrees, it is only necessary to obtain the contour shape of only one side.

The boat shape (first outline shape) 22 on which the wavelength conversion surface 23 in the radiation angle vertical direction θv of the second luminous flux 14 is provided is a shape (first contour shape) along the first plane Sv including the radiation angle vertical direction θv. can be expressed as the contour shape of The first contour shape 22 of the first surface Sv can be represented by XY coordinates with the optical axis 14a as the X axis and the semiconductor light source (LD) 12 as the origin. It can be obtained as a first contour shape 22 .

Two points (x1, y1) and (x2, y2) that differ by the radiation angle dθ on the XY plane of the wavelength conversion surface 23 in the direction of the radiation angle θ are given by the following equation (4).
y1=x1·tan(θ+dθ)
y2=x2·tan θ (4)
Therefore, by setting the first contour shape 22 in which the wavelength conversion surface 23 is arranged so that the distance between these two points is proportional to the radiation intensity of the radiation angle θ, the wavelength conversion surface 23 of the second luminous flux 14 It is possible to make the irradiation intensity to be constant. For that purpose, the two points (x1, y1) and (x2, y2) should satisfy the following condition (1).
(x2-x1) ² + (y2-y1) ² = (αg(θ+dθ/2)) ² (1)
θ is the angle from the X-axis, and α is the constant of proportionality.

Therefore, as shown in FIG. 9, for one coordinate P1 (x1, y1), a coordinate P2 (x2, y2) that satisfies the formula of condition (1) (hereinafter, formula (1)) is obtained, By connecting them with an interpolating spline line, a first contour shape 22 having a substantially equal irradiation amount from the second light flux 14 is obtained for a unit light emitting portion separated by a unit angle from the optical axis (X-axis) 14a. can be done. One method of drawing the first contour shape 22 is to determine the radial length G (equation (5)) corresponding to the right side of equation (1) for each appropriate unit of the radiation angle θ, for example, every 2 degrees, and use the reference (the position of the radiation angle (.theta.+d.theta.)) P, the position on the next radiation angle .theta.
G=α·g(θ+dθ/2) (5)

FIG. 10 shows the result of obtaining the radius (radiation length) G at intervals of 2 degrees from the radiation angle θ of 23 degrees. Further, FIG. 11 shows the result of obtaining the first contour shape 22 by drawing. The constant of proportionality α is set based on the light-emitting area and light-emitting surface luminance required for the lighting fixture. In this example, the constant of proportionality (multiplier) α is set to 45. This constant of proportionality α can be appropriately set by drawing once. In FIG. 11, the position P1 from which drawing is started is such that the radiation angle (beam intensity 1/e ² ) in the vertical direction θv of the radiation angle of the second light flux 14 in this example is 45 degrees, and the second light flux 14 is In order to maximize the use, the position closest to the cylindrical lens 15a with a radiation angle θ of 24 degrees was selected as a value larger than the half angle of the radiation angle. The constant of proportionality α and the coordinates of the initial position P1 for obtaining the first contour shape 22 may be set as appropriate. Also, the angular division for obtaining the first contour shape 22 may not be 2 degrees, but may be 1 degree or less, or may be 2 degrees or more. Positions P2 to P13 are obtained in order as intersections of radius G and radiation angle θ shown in FIG. That is, the position P2 is determined as the intersection of the circle with the radius G of 6.733295 from the position P1 and the line with the radiation angle θ of 22 degrees, and the positions P3 to P13 are similarly determined.

The second light flux (beam light) 14 output from the semiconductor light source 12 through the optical system 19 is symmetrical with respect to the optical axis 14a, which is the X axis, so that it is a mixture containing the wavelength-converted light 32 per unit length. The contour shape 22 in which the emission intensity of the light 33 is constant is obtained by expanding the shape 22 obtained above symmetrically with respect to the X axis. By arranging the wavelength conversion surface 23 along the first contour shape 22, the irradiation intensity of the second light flux 14 per unit length of the wavelength conversion surface 23 becomes constant, and the wavelength converted per unit length becomes constant. A light-emitting unit 20 in which the mixed light 33 has a constant emission intensity is obtained.

It is also possible to obtain the first profile 22 by solving equation (1). As shown in FIG. 12(a), equation (1) is transformed into a quadratic equation of x2, and as shown in FIG. 12(b), quadratic We can solve the equation to get the coordinates P2(x2, y2). FIG. 10 shows the X coordinate and Y coordinate of each position P obtained as calculated values. Further, FIG. 13 shows a line connecting the coordinates of each position P obtained by calculation with an interpolating spline line. It is developed symmetrically with respect to the X-axis. In either case, the first contour shape 22 is symmetrical with respect to the optical axis 14a of the second light beam 14, and the wavelength conversion surface 23 has a boat shape, that is, the semiconductor light source 12 side of the optical axis 14a. It is arranged along the boat-shaped first contour shape 22 with the stern side and the opposite side being the bow side (tip side). That is, the first contour shape 22 has the semiconductor light source 12 as the origin, the optical axis 14a as the X axis, the position P1 (x1, y1) apart in the Y direction as the starting point, and once along the plus direction of the X axis. A convex curve is drawn on the side opposite to the X-axis so as to move away from the X-axis in the Y direction, and then it gradually approaches the X-axis direction and intersects the X-axis so as to form a tip that serves as a bow.

FIG. 14 shows a contour shape 22 on which the wavelength conversion surface 23 is provided when the radiation angles of the second light flux 14 entering the light emitting unit 20 are different. When the radiation angle becomes small, the first contour shape (boat-shaped contour shape) 22 becomes a shape extending in the direction of the optical axis 14a serving as the X-axis. Therefore, in the optical system 19, by controlling the radiation angle of the second light beam 14 input to the light emitting unit 20 by the cylindrical lenses 15a and 15b, etc., the light emitting unit 20 outputs the illumination light 35. For example, length, width, etc. can be controlled.

FIG. 15(a) shows the illumination device 1 in which the wavelength conversion surface 23 is arranged along the first outline shape 22 designed on the premise of only the distribution of the light flux 14 input to the light emitting unit 20 as described above. A change in the luminance ratio of the light emitting surface from the wavelength conversion surface 23 (the ratio of the luminance of the front and rear portions to the luminance of the central portion of the first outline shape 22, specifically described in each figure) is measured from the semiconductor light source 12 along the optical axis 14a. is shown for distance along . FIG. 15(b) shows the change in the above-mentioned light emitting surface luminance ratio converted into an angle (radiation angle) θ from the optical axis 14a. The first contour shape 22 obtained as described above is a calculated shape suitable for wavelength-converting the light flux 14 input from the semiconductor light source 12 to the light emitting unit 20 with equal intensity. However, part of the second light flux (beam light) 14 is reflected on the wavelength conversion surface 23 without being wavelength-converted, hits the wavelength conversion surface 23 on the bow side 3, and is mixed light including wavelength-converted light 32. 33 is generated. Further, since the wavelength conversion surfaces 23 are closer to each other toward the bow side 3, the brightness of the wavelength conversion surfaces 23 increases toward the bow side 3. FIG. It can be seen from FIGS. 15(a) and (b) that these influences actually appear. In order to obtain more uniform light emission brightness in the entire light emitting unit 20, it is desirable to correct the high brightness of the bow side 3. FIG.

FIG. 16(a) shows the result of approximating the change in the light emitting surface luminance ratio obtained by the measurement as a polynomial of the radiation angle θ. Regarding the light emitting surface luminance ratio, the amount of increase on the bow side 3 is greater than the amount of decrease on the stern side 2 . Therefore, as shown in FIG. 16(b), the luminance ratio of the light-emitting surface 3 on the bow side 3 is approximated by a polynomial when the intermediate radiation angle θ is 8 degrees, and is obtained as a correction function h(θ). For the light intensity distribution obtained by correcting the light intensity of the light flux 14 of No. 2 with the correction function h(θ), the arrangement of the wavelength conversion surface 23 was obtained so that the irradiation amount per unit area is constant. The contour shape 22 on which the wavelength converting surface 23 is arranged satisfies the following condition (2).
(x2-x1) ² + (y2-y1) ² = (α·g(θ+dθ/2)·h(θ)) ²
... (2)

Based on the equation of condition (2) (equation (2) below), the first contour shape 22 for arranging the wavelength conversion surface 23 can be obtained in the same manner as in equation (1).

As described above, the illumination device 1 includes the semiconductor light source 12 and either the horizontal direction θp or the vertical direction θv of the radiation angle of the first light beam 13 output from the semiconductor light source 12 (in the above description, the horizontal An optical system 19 including a first optical element 15 for collimating the component in the direction θp) into parallel light, and a wavelength converter for outputting light that has been irradiated with a second light flux 14 output from the optical system 19 and has been wavelength-converted. and a light emitting unit 20 including a surface 23 . The wavelength conversion surface 23 is a first plane Sv (XY plane) including the other of the horizontal direction of radiation angle θp and the vertical direction of radiation angle θv (the vertical direction of radiation angle θv in the above description). It extends along the contour shape 22 . The first contour shape 22 is boat-shaped, and is symmetrical with respect to the X-axis, with the optical axis 14a of the second light beam 14 as the X-axis. , the XY coordinates indicating the first surface Sv may satisfy the formula (1).

Furthermore, the first contour shape 22 may be a shape considering a function h(θ) for correcting including the contribution of the reflection component of the second light flux 14 on the wavelength conversion surface 23 . That is, it may satisfy the expression (2). In the above, the function h(θ) for correcting the intensity of the second light flux 14 given by a Gaussian function is obtained when the radiation angle θ is an appropriate value or less, for example, 8 degrees or less, and the radiation angle θ is 8 degrees. The following bow side 3 first profile 22 is corrected. The range of the function h(θ) to be corrected is not limited to 8 degrees or less, and may be the range of all radiation angles, or may be one that corrects only a limited area on the bow side 3 . Further, in the lighting device 1 that does not require much uniformity of luminance, or in the case where the radiation angle range of the second light flux 14 input to the light emitting unit 20 is narrow and the influence of reflection on the wavelength conversion surface 23 is small, the function h The correction by (θ) may be omitted.

In either case, the resulting first contour shape 22 is symmetrical with respect to the optical axis 14a of the second light beam 14, with the semiconductor light source 12 side of the optical axis 14a being the stern side 2 and the opposite side being the bow. It becomes a boat shape with side 3. The first contour shape 22 obtained in this way is the second light beam 14 and the second light beam 14 for the unit light emitting portion divided by the unit angle from the optical axis 14a with the semiconductor light source 12 as the origin. It is possible to provide the illumination device 1 having a shape in which the irradiation amount of the light emitted by the unit light-emitting portions is substantially equal, and which has more uniform surface emission luminance in the longitudinal direction. Therefore, by irradiating the wavelength conversion surface (phosphor) 23 and converting it into a mixed light 33 containing the wavelength-converted light 32, a wider range can be illuminated, the structure is simple, and the light utilization efficiency is high. A device 1 can be provided. It includes a wavelength conversion surface provided along a first contour shape, and the first contour shape is an irradiation amount of the second light beam for a unit light emitting portion separated by a unit angle from an optical axis with the semiconductor light source as an origin. are approximately equal. Therefore, it is possible to provide a lighting device with more uniform surface emission luminance.

FIG. 17 shows an example of a different illumination device. As shown in the cross section of FIG. 17(a), this lighting device 1a, like the lighting device 1 described above, has an output surface 26 parallel to the first surface Sv and, on the other hand, perpendicular to the XY plane, for example. The inner surface 25a of the side wall 25 is inclined to reflect the light flux 14 in the positive Z-axis direction. Therefore, the white mixed light 33 containing the light 32 wavelength-converted by the wavelength conversion surface 23 provided on the inner surface 25 a is efficiently output in the direction of the emission surface 26 . Further, in the lighting device 1 described above, the light-emitting surface becomes brighter toward the bow side 3, but by inclining the wavelength conversion surface 23, the effect of alleviating the high-luminance portion can be obtained. FIG. 17(b) is a perspective view showing an example of the entire illumination device 1a with the wavelength conversion surface 23 inclined, and FIG.

In addition, it is possible to increase the width of the diffusion member 21 on the bow side 3 of the light emitting unit 20 by positively inclining the wavelength conversion surface 23 by giving a gradient to the inner surface 25a on the bow side 3 where the light emission intensity increases. is. Therefore, it is possible to provide a lighting device 1 having a light-emitting surface that is generally rectangular or nearly rectangular as shown in FIG. 17(d). In other words, the wavelength-converted light 32 and/or the mixed light 33 is emitted by controlling the gradient of the wavelength conversion surface 23 (angle with respect to the first surface Sv) together with the function h(θ) for correcting the light intensity or separately. Alternatively, by controlling the direction of diffusion to control the area of the exit surface (the area of the diffusion member), it is possible to provide an illumination device that outputs the illumination light 35 with more uniform luminance.

FIG. 18 shows a cross-sectional view of an example of yet another lighting device. In this illuminating device 1b, the emission surfaces 26 are provided on both sides of the wavelength conversion surface 23, and the first emission surface 26a and the second emission surface 26b, which are the front and back (top and bottom, left and right, or front and back), are provided. include. The first emission surface 26a outputs the illumination light 35 in the positive Z-axis direction, and the second emission surface 26b outputs the illumination light 35 in the negative Z-axis direction. In both lighting devices 1a and 1b, the light-emitting unit 20 includes the diffusion member 21 covering the emission surface 26, like the lighting device 1 described above.

FIG. 19 shows another example of a different illumination device. This illumination device 1c is configured such that two sets of illumination devices 1 are combined so that the optical axes of the semiconductor light sources 12 face each other in a direction parallel to the first surface. High-intensity illumination light 35 can be output through the LED.

As explained with these illumination devices 1, 1a to 1c (hereinafter referred to as illumination device 1) as an example, the illumination device 1 of the present invention includes a semiconductor light source 12 and one beam radiation angle. An optical system 19 for collimating an angle into parallel light, and a light emitting unit 20 having a contour shape 22 for irradiating with equal irradiation intensity based on the radiation angle-beam intensity distribution (Gaussian distribution) of the uncollimated beam light component, The wavelength conversion surface 23 arranged in the outline shape 22 is irradiated with light 33 which is wavelength-converted by the irradiation of the beam light, and the light 33 is extracted as illumination light 35 through the diffusion member 21 . The contour shape 22 of the member provided with the wavelength conversion surface 23 irradiated with the collimated beam light, in this example, the inner surface 25a, is calculated based on the radiation angle-beam intensity distribution curve (Gaussian distribution) of the radiation angle component not collimated. , and have emission lengths with equal emission intensities that are corrected by measurement.

In the illumination device 1, even if the light 33 wavelength-converted by the collimated beam light (second light flux) 14 is taken out as illumination light 35 on one side of the optical axis plane (first plane) Sv of the collimated radiation angle. It may be set so as to be extracted as illumination light 35 on both sides. A typical shape of the diffusing member 21 of the lighting device may be the same as or similar to the shape 22 of the beam light equal irradiation intensity surface calculated based on the radiation angle-beam radiation intensity distribution curve (Gaussian distribution), that is, the boat shape. It may well have different shapes, such as square.

A typical optical element 15 for collimation in the optical system 19 is a cylindrical lens 15a. The adjustment may widen or narrow the radiation angle of the light flux 14 irradiating the wavelength conversion surface 23 of the light emitting unit 20 . Accordingly, the optical system 19 may include first and second optical elements that control the horizontal and vertical radiation angles θp and θv, respectively, and control both the horizontal radiation angle θp and the vertical radiation angle θv. It may also include a single optical element with components such as toric surfaces.

This illumination device 1 directly irradiates the phosphor on the wavelength conversion surface 23 with a beam from a semiconductor light source 12 such as a laser diode by optical space propagation. For this reason, it is possible to suppress a decrease in light intensity due to transmission and reflection of the light guide, and the lighting device has a high light utilization efficiency of the light obtained from the semiconductor light source 12, does not require a complicated structure, suppresses manufacturing costs, and emits uniform light. surface can be formed. Therefore, it is suitable for general illumination such as a ceiling light and an alternative to a fluorescent lamp.

Claims (12)

a semiconductor light source;
an optical system including a first optical element for collimating either one of the components in the horizontal direction of the radiation angle or in the vertical direction of the radiation angle of the first light flux output from the semiconductor light source into parallel light;
a light-emitting unit including a wavelength conversion surface for outputting wavelength-converted light irradiated by the second light flux output from the optical system;
The wavelength conversion surface extends along a first contour shape along a first surface including either the horizontal direction of the radiation angle or the vertical direction of the radiation angle, and the first contour shape is the It is symmetrical with respect to the optical axis of the second light beam, and at least part of the first contour shape has the semiconductor light source as an origin, the optical axis as the X axis, and the XY coordinates indicating the first plane. A lighting device that satisfies the following conditions.
(x2-x1) ² + (y2-y1) ² = (αg(θ+dθ/2)) ²
y1=x1·tan(θ+dθ)
y2=x2·tan θ
g(θ)=exp(−θ ² /(2×σ ² ))
is the angle from the X-axis, α is the constant of proportionality, and σ2 is the value indicating the dispersion of the component of the ^second light beam in the other direction. a semiconductor light source;
an optical system including a first optical element for collimating either one of the components in the horizontal direction of the radiation angle or in the vertical direction of the radiation angle of the first light flux output from the semiconductor light source into parallel light;
a light-emitting unit including a wavelength conversion surface for outputting wavelength-converted light irradiated by the second light flux output from the optical system;
The wavelength conversion surface extends along a first contour shape along a first surface including either the horizontal direction of the radiation angle or the vertical direction of the radiation angle, and the first contour shape is the It is symmetrical with respect to the optical axis of the second light beam, and the first contour shape has the semiconductor light source as the origin and the optical axis as the X axis in XY coordinates indicating the first surface, and satisfies the following conditions: Satisfied, lighting equipment.
(x2-x1) ² + (y2-y1) ² = (α·g(θ+dθ/2)·h(θ)) ²
y1=x1·tan(θ+dθ)
y2=x2·tan θ
g(θ)=exp(−θ ² /(2×σ ² ))
where θ is the angle from the X-axis, α is the constant of proportionality, σ2 is the value indicating the dispersion of the component of the ^second light beam in the other direction, and the function h(θ) is the wavelength conversion surface. It is a function that corrects at least the contribution of the reflected component of the second beam. In claim 1,
The illumination device, wherein the first contour shape is a boat shape whose tip is in the direction of the X-axis, and the shape of the tip side of the first contour shape satisfies the following conditions.
(x2-x1) ² + (y2-y1) ² = (α·g(θ+dθ/2)·h(θ)) ²
However, the function h(θ) is a function that corrects at least the contribution of the reflection component of the second light flux on the wavelength conversion surface. a semiconductor light source;
an optical system including a first optical element for collimating either one of the components in the horizontal direction of the radiation angle or in the vertical direction of the radiation angle of the first light flux output from the semiconductor light source into parallel light;
a light-emitting unit including a wavelength conversion surface for outputting wavelength-converted light irradiated by the second light flux output from the optical system;
The wavelength conversion surface extends along a first contour shape along a first surface including either the horizontal direction of the radiation angle or the vertical direction of the radiation angle, and the first contour shape is the A lighting device which is symmetrical with respect to the optical axis of the second luminous flux and has a boat shape with the semiconductor light source side of the optical axis as the stern and the opposite side as the bow. a semiconductor light source;
an optical system including a first optical element for collimating either one of the components in the horizontal direction of the radiation angle or in the vertical direction of the radiation angle of the first light flux output from the semiconductor light source into parallel light;
a light-emitting unit including a wavelength conversion surface for outputting wavelength-converted light irradiated by the second light flux output from the optical system;
The wavelength conversion surface extends along a first contour shape along a first surface including either the horizontal direction of the radiation angle or the vertical direction of the radiation angle, and the first contour shape is the the second light flux and the second light flux with respect to unit light emitting portions that are symmetrical with respect to the optical axis of the second light flux, and that the first contour shape is divided by unit angles from the optical axis with the semiconductor light source as the origin; An illumination device, wherein the second light beam is reflected by other unit light-emitting portions and has approximately the same irradiation amount. In any one of claims 1 to 5,
The lighting device, wherein the light emitting unit includes an output surface parallel to the first surface. In claim 6,
The illumination device, wherein the exit surface includes a first exit surface and a second exit surface sandwiching the wavelength conversion surface. In claim 6 or 7,
A lighting device, wherein the light-emitting unit includes a diffusion member that covers the emission surface. In any one of claims 1 to 8,
The illumination device, wherein the first optical element is a cylindrical lens. In any one of claims 1 to 9,
The illumination device, wherein the optical system includes a second optical element that controls a radiation angle of the other component of the first light flux. In any one of claims 1 to 8,
The illumination device, wherein the first optical element includes a component that controls a radiation angle of the other component of the first light flux. The wavelength at which the component of either the horizontal direction of the radiation angle or the vertical direction of the radiation angle of the first beam output from the semiconductor light source is irradiated by the second beam collimated into parallel light, and the wavelength of the converted light is output. A light emitting unit comprising a conversion surface,
The wavelength conversion surface extends along a first contour shape along a first surface including either the horizontal direction of the radiation angle or the vertical direction of the radiation angle, and the first contour shape is the It is symmetrical with respect to the optical axis of the second light beam, and at least part of the first contour shape has the semiconductor light source as an origin, the optical axis as the X axis, and the XY coordinates indicating the first plane. A light-emitting unit that satisfies the following conditions.
(x2-x1) ² + (y2-y1) ² = (αg(θ+dθ/2)) ²
y1=x1·tan(θ+dθ)
y2=x2·tan θ
g(θ)=exp(−θ ² /(2×σ ² ))
is the angle from the X-axis, α is the constant of proportionality, and σ2 is the value indicating the dispersion of the component of the ^second light beam in the other direction.

Images