WO2021193758A1

WO2021193758A1 - Bulk lens, light-emitting body, and method for designing bulk lens

Info

Publication number: WO2021193758A1
Application number: PCT/JP2021/012370
Authority: WO
Inventors: 大塚　晃; 玉置　智
Original assignee: ラボ・スフィア株式会社
Priority date: 2020-03-24
Filing date: 2021-03-24
Publication date: 2021-09-30
Also published as: JPWO2021193758A1; JP7267661B2

Abstract

This bulk lens 1e includes: an emission surface 36c formed by a curved surface having a continuous curvature; an optical transmission part; a rear outer wall surface 44e; and a recess part that is formed by a ceiling part 42e and a side wall 43e provided inside the optical transmission part and accommodates a planar light emitting element 91e. The curvature of a central region is set so that a difference between an emission angle of light emitted from a first emission point of a central region of the emission surface 36c through the center of the ceiling part 42e and an emission angle of light emitted from a second emission point of the central region through the ceiling part 42e adjacent to the side wall 43e falls within a first emission angle range. The curvature of a peripheral region and the curvature of the rear outer wall surface 44e are set so that the difference between an emission angle of light incident from the uppermost side of the side wall 43e, reflected by the rear outer wall surface 44e, and emitted from a third emission point of the peripheral region of the emission surface 36c and an emission angle of light incident from a position away from the ceiling part 42e of the side wall 43e, reflected by the rear outer wall surface 44e, and emitted from a fourth emission point of the peripheral region falls within a second emission angle range.

Description

How to design bulk lenses, illuminants and bulk lenses

A bulk type lens that can efficiently collect the light emitted from a high-output planar light emitting element such as a light emitting diode (LED) that emits surface light and emit it with a relatively narrow irradiation angle, and the bulk type lens and surface. The present invention relates to a light emitting body in which a diode is combined, and further to a method for designing a bulk type lens.

The intensity of the emitted light from the light emitting surface of an LED light source having a flat light emitting surface is reduced by the cosine function of the irradiation angle defined by the inclination of the light emitting surface from the normal direction, and is 2 of the distance between the LED light source and the irradiation position. It is inversely proportional to the power. For example, in road lighting, when irradiating a road surface that is a long distance away from the lighting equipment on the shoulder of the road, the angle between the optical axis of the irradiation light and the road surface becomes small, and high illuminance cannot be obtained. On the other hand, the distance between the LED light source and the irradiation position is short directly under the lighting equipment, and the illuminance is high because the angle formed by the optical axis of the irradiation light and the road surface is at a right angle. Therefore, it is difficult to make the illuminance uniform on the road surface away from the luminaire and directly under the luminaire.

On the other hand, in order to improve the light collection efficiency, a bulk type lens 1d having an optical design in which the curvature at the connection portion between the first exit surface 33 and the second exit surface 34 as shown in FIG. 11 is discontinuous is known. (See Patent Document 1). In the conventional bulk lens 1d shown in FIG. 11, light emitted from a central light emitting point located at the center of a large-area LED light source 91d configured for high output, and light in an optical path having a small irradiation angle is emitted from a recessed ceiling portion 42d. After being incident on the bulk type lens 1d, it is emitted from the first exit surface 33 on the upper part of the bulk type lens 1d. On the other hand, the light emitted from the central emission point at a large emission angle is incident from the side wall 43d of the recess, reflected by the rear outer wall surface 44d of the bulk lens 1d, and then the second exit surface of the upper portion of the bulk lens 1d. Emit from 34. The optical path 65-1'shown by the broken line in FIG. 12 has the same emission angle as the optical path 65-1 emitted from the central emission point, but emits light from the end emission point on the right end side of the LED light source 91d. Therefore, it is deviated from the central light emitting point by a distance d. The optical path 65-1'is incident on the bulk lens 1d with the side wall 43d of the recess as the incident surface, and is emitted from the second exit surface 34 of the bulk lens 1d.

The optical path 65-2'shown by the broken line in FIG. 12 is the same as the optical path 65-2 whose emission angle is indicated by the solid line emitted from the central emission point, and emits light with the left end side of the LED light source 91d as the end emission point. doing. Since the optical path 65-2'starts at a distance d from the central light emitting point, it is incident on the ceiling portion 42d different from the side wall 43d of the recess originally designed for the optical path 65-2. Then, the light of the optical path 65-2'is emitted from a position of the second exit surface 34 different from the original design. In the conventional bulk type lens 1d, when the area of the light emitting surface of the LED light source 91d is large, the light of the optical path emitted from the end light emitting point is wide from the emission surface different from the initial design to the irradiation angle different from the initial design. It emits light at the irradiation angle, and the light collection efficiency decreases. In order to avoid this problem, it can be reduced by increasing the distance between the first exit surface 33 and the second exit surface 34, but a new problem arises in which the bulk type lens 1d shape becomes large.

In the case of the LED light source 91d having a large area light emitting surface used for a large stadium with a scale of 100,000 people, road lighting, etc., the irradiation angle and irradiation light of the bulk lens 1d are taken into consideration even from the end light emitting point. It is required to design the strength. However, in the conventional bulk lens 1d shown in FIG. 11, since the curvature at the connection portion between the first emission surface 33 and the second emission surface 34 is discontinuous, the positions of a plurality of dispersed light emitting points are taken into consideration. , It is difficult to design the irradiation angle and irradiation light intensity of the bulk lens 1d. As described above, the conventional bulk type lens 1d has a problem that the light collection efficiency tends to decrease when illuminating a wide irradiation area such as a large stadium or road lighting.

Japanese Unexamined Patent Publication No. 2005-93622

The present invention is a bulk lens having a compact structure, capable of achieving a narrow irradiation angle even by using a large-area planar light emitting element, and efficiently illuminating a wide irradiation area with a light intensity distribution having excellent uniformity. It is an object of the present invention to provide a light emitting body in which a bulk type lens and a planar light emitting element are combined, and a method for designing a bulk type lens.

Means to solve problems

The first aspect of the present invention relates to a bulk type lens that houses a main light emitting portion of a planar light emitting element. The bulk lens according to the first aspect has (a) an exit surface composed of a curved surface whose curvature continuously changes, (b) an optical transmission unit composed of an optical medium in contact with the exit surface, and (c). It is composed of a rear outer wall surface in contact with the optical transmission unit, (d) a ceiling portion provided inside the optical transmission portion, and a side wall connected to the ceiling portion, and is provided with a recess for accommodating the main light emitting portion. In the bulk type lens according to the first aspect, when the normal direction of the light emitting surface passing through the center of the light emitting surface of the planar light emitting element is defined as the optical axis and the inclination angle from this optical axis is defined as the irradiation angle, For light emitted from the center of the light emitting surface of the planar light emitting element, the light emitted from the first emission point in the central region of the exit surface through the center of the ceiling portion and the irradiation angle of the light emitted from the first emission point and the ceiling portion near the side wall pass through. The angle of the tangent plane with respect to the curved surface at the first and second emission points is set so that the difference in the irradiation angles of the light emitted from the second emission point in the central region is within the first irradiation angle range of 10 degrees or less. ing. Further, in the bulk type lens according to the first aspect, the irradiation angle of light incident from the uppermost portion of the side wall, reflected by the first reflection point on the rear outer wall surface, and emitted from the third emission point in the peripheral region of the emission surface, and Light incident from a position away from the ceiling of the side wall is reflected by the second reflection point on the rear outer wall surface, and the difference in irradiation angle emitted from the fourth exit point in the peripheral region is within 10 degrees of the second irradiation angle range. Therefore, the angle of the tangent plane with respect to the curved surface at the third and fourth exit points and the angle of the tangent plane of the rear outer wall surface at the first and second reflection points are set. Further, in the bulk type lens according to the first aspect, the first irradiation angle range and the second irradiation angle range are the same.

A second aspect of the present invention is a planar light emission fixed in a predetermined positional relationship so as to be housed in a recess of the bulk type lens according to the first aspect and the bulk type lens according to the first aspect. The gist is that it is a light emitting body including an element. Therefore, similarly to the bulk type lens according to the first aspect, in the light emitting body according to the second aspect, the normal direction of the light emitting surface passing through the center of the light emitting surface of the planar light emitting element is set as the optical axis, and this light is used. When the angle of inclination from the axis is defined as the irradiation angle, the light emitted from the center of the light emitting surface of the planar light emitting element is emitted from the first emission point in the central region of the exit surface through the center of the ceiling portion. The first and first irradiation angles are such that the difference between the irradiation angle of the light to be emitted and the irradiation angle of the light emitted from the second exit point in the central region through the ceiling near the side wall is within 10 degrees of the first irradiation angle range. 2 The angle of the tangent plane with respect to the curved surface at the exit point is set. Further, in the light emitting body according to the second aspect, the irradiation angle of the light incident from the uppermost portion of the side wall, reflected by the first reflection point on the rear outer wall surface, and emitted from the third emission point in the peripheral region of the exit surface, and the side wall. The light incident from a position away from the ceiling is reflected by the second reflection point on the rear outer wall surface, and the difference in irradiation angle emitted from the fourth exit point in the peripheral region is within the second irradiation angle range of 10 degrees or less. As described above, the angle of the tangent plane with respect to the curved surface at the third and fourth exit points and the angle of the tangent plane of the rear outer wall surface at the first and second reflection points are set. Further, in the light emitting body according to the second aspect, the first irradiation angle range and the second irradiation angle range are the same.

A third aspect of the present invention is (p) an emission surface made of a curved surface whose curvature continuously changes, an optical transmission part made of an optical medium in contact with the emission surface, a rear outer wall surface in contact with the optical transmission part, and light. The step of drawing the initial design outline, which is composed of the ceiling part provided inside the transmission part and the side wall connected to this ceiling part and has a recess for accommodating the main light emitting portion, and (q) the surface shape accommodated in this recess. The steps to determine the relative position of the light emitting element, (r) the first reflection point where the light incident from the uppermost part of the side wall reaches the rear outer wall surface, and the light incident from the position away from the ceiling part of the side wall are the rear outer wall surface. The step of determining the second reflection point to reach (s) and the rear outside at the first and second reflection points so that the light reflected at the first and second reflection points reaches the peripheral region of the exit surface. The step of setting the angle of the tangent plane of the wall surface, (t) the irradiation angle of the light emitted from the first emission point in the central region of the emission surface through the center of the ceiling, and the center through the ceiling near the side wall. A step of setting the angle of the tangent plane with respect to the curved surface at the first and second emission points so that the difference between the irradiation angles of the light emitted from the second emission point of the region is within the first irradiation angle range of 10 degrees or less. , (U) The irradiation angle of the light reflected at the first reflection point and emitted from the third emission point in the peripheral region of the exit surface, and the irradiation reflected by the second reflection point and emitted from the fourth emission point in the peripheral region. The angle of the tangent plane with respect to the curved surface at the third and fourth exit points and the tangent plane of the rear outer wall surface at the first and second reflection points so that the angle difference is within the second irradiation angle range of 10 degrees or less. The gist is that it is a bulk type lens design method including a step of setting an angle.

According to the present invention, it is possible to efficiently use the size of the light emitting surface of the planar light emitting element having a large light emitting surface area, and the compact structure affects the influence of light emitted from a position away from the central light emitting point. It is possible to provide a design method for a bulk type lens, a light emitter, and a bulk type lens that can efficiently illuminate a wide irradiation area with a light intensity distribution having excellent uniformity while reducing the number of light sources and increasing the light collection efficiency with a narrow irradiation angle. can.

It is a schematic cross-sectional view which shows the locus of a plurality of optical paths transmitted through the bulk type lens which concerns on 1st Embodiment of this invention. It is a schematic cross-sectional view explaining the concept of the design concept of the exit surface of the bulk type lens which concerns on 1st Embodiment. It is a top view (plan view) which shows the classification of the exit surface defined in the bulk type lens which concerns on 1st Embodiment. It is a schematic cross-sectional view explaining the structure of the semiconductor light emitting element housed in the recess of the bulk type lens which concerns on 1st Embodiment. It is a simplified flowchart explaining the outline of the design method of the bulk type lens which concerns on 1st Embodiment. FIG. 5 is a schematic cross-sectional view showing the loci of optical paths of a plurality of emitted lights having a position deviated by a distance d from the central light emitting point in the bulk lens according to the first embodiment. It is a schematic cross-sectional view which shows the locus of a plurality of optical paths transmitted through the bulk type lens which concerns on 2nd Embodiment of this invention. FIG. 5 is a schematic cross-sectional view showing the loci of optical paths of a plurality of emitted lights having a position deviated from the central light emitting point by a distance d as the light emitting point in the bulk type lens according to the second embodiment. It is a schematic cross-sectional view which shows the locus of an optical path in the cross section along the X-axis direction orthogonal to the optical axis of the bulk type lens which concerns on 3rd Embodiment of this invention. It is a schematic cross-sectional view which shows the locus of an optical path in the cross section along the Y-axis direction orthogonal to the optical axis and the X-axis of the bulk type lens which concerns on 3rd Embodiment. It is a schematic bottom view which shows the shape seen from the bottom surface of the bulk type lens which concerns on 3rd Embodiment. It is a schematic cross-sectional view which shows the locus of an optical path in the cross section along the X-axis direction orthogonal to the optical axis of the bulk type lens which concerns on 4th Embodiment of this invention. It is a schematic cross-sectional view which shows the locus of an optical path in the cross section along the Y-axis direction orthogonal to the optical axis and the X-axis of the bulk type lens which concerns on 4th Embodiment. It is a schematic bottom view which shows the shape seen from the bottom surface of the bulk type lens which concerns on 4th Embodiment. It is a schematic cross-sectional view which shows the locus of a plurality of optical paths transmitted through a conventional bulk type lens. FIG. 5 is a schematic cross-sectional view showing the loci of optical paths of a plurality of emitted light having a position deviated from the central light emitting point by a distance d as the light emitting point in the bulk type lens of FIG.

Next, the first to fourth embodiments of the present invention will be described with reference to the drawings. In the description of the drawings below, the same or similar parts are designated by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the plane dimensions, the ratio of the thickness of each layer, etc. are different from the actual ones. Therefore, the specific thickness and dimensions should be determined in consideration of the following explanation. In addition, it goes without saying that the drawings include parts having different dimensional relationships and ratios from each other.

Further, the first to fourth embodiments shown below exemplify devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is based on the material of the component parts. The shape, structure, arrangement, etc. are not specified as follows. The technical idea of the present invention may be modified in various ways within the technical scope specified by the claims.

(First Embodiment)
As shown in FIG. 1A, the bulk type lens 1e according to the first embodiment of the present invention is a bulk type lens 1e that houses a main light emitting portion of a planar light emitting element 91e such as an LED. The bulk lens 1e according to the first embodiment includes an exit surface 36c formed of a curved surface whose curvature continuously changes, a bulk-shaped optical transmission unit 39e composed of an optical medium in contact with the exit surface 36c, and a bulk-shaped optical transmission unit 39e. It is composed of a rear outer wall surface 44e in contact with the optical transmission unit 39e, a ceiling portion 42e provided inside the optical transmission unit 39e, and a side wall 43e connected to the ceiling portion 42e. 43e) is provided. The rear outer wall surface 44e optically faces the exit surface 36c. The term "optically opposed" means that the exit surface 36c and the rear outer wall surface 44e do not have to face each other in substantially parallel directions, and the light reflected by the rear outer wall surface 44e may reach the exit surface 36c. Meaning. The recesses (42e, 43e) are formed in the ceiling portion 42e and the ceiling portion 42e so that the ceiling portion 42e is located inside the optical transmission portion 39e along the direction of the exit surface 36c from a part of the rear outer wall surface 44e. It is composed of a side wall 43e to be connected, and houses a main light emitting portion of a planar light emitting element 91e such as an LED. In the following description, for the sake of convenience, the rear outer wall surface 44e is described so that it can be designed under the total reflection condition. A structure that has undergone specular reflection treatment such as a high metal film may be used.

The expression "consisting of a curved surface whose curvature changes continuously" that defines the shape of the exit surface 36c is a mathematical definition of a "smooth curved surface". For example, in the structures shown in FIGS. 11 and 12, the first exit surface 33 having a small radius of curvature and the second exit surface 34 having a radius of curvature larger than the radius of curvature of the first exit surface 33 intersect, and the first The curvature is discontinuous at the intersection of the exit surface 33 and the second exit surface 34. Since the structures shown in FIGS. 11 and 12 have a three-dimensional shape, the curvature discontinuity points of the first exit surface 33 and the second exit surface 34 on the cross-sectional views of FIGS. 11 and 12 are curvature discontinuities in three-dimensional coordinates. Become a line. On the other hand, since the exit surface 36c of the bulk lens 1e according to the first embodiment is a curved surface whose curvature continuously changes, there is no curvature discontinuity line.

For example, as shown in FIG. 1B, the exit surface 36c constitutes a curved surface whose curvature continuously changes as an envelope surface of a plurality of arcs. In FIG. 1B, when the normal direction of the light emitting surface passing through the center of the light emitting surface of the planar light emitting element 91e is defined as the “optical axis” of the bulk type lens 1e according to the first embodiment, the center point on the optical axis is defined. As an _{encircling surface} of an arc with a radius of curvature R ₀ centered on O v1, an arc with a radius of curvature R _11, an arc with a radius of curvature R ₁₂ = R _11, an arc with a radius of curvature R _{13, and} an arc with a radius of curvature R ₁₄ = R _13. , The central region 36C _c of the exit surface 36c is configured.
R ₁₃ > R ₁₁ > R ₀ …… (1a)
R ₁₄ > R ₁₂ > R ₀ …… (1b)

Has a relationship.

On the other hand, the arc of curvature radius R ₁₅ around the center point O _v2 on the optical axis, the circular arc of the envelope surface of the curvature radius R ₁₆ = R ₁₅ is continuous to the envelope surface of the central region 36C _c of the exit surface 36c that As a result, the peripheral region 36C _o of the exit surface 36c is formed, so that the curvature is a curved surface that continuously changes.

R ₁₅ > R ₁₃ …… (2a)
R ₁₆ > R ₁₅ …… (2b)

Has a relationship.

The envelope surface forming the peripheral region 36C _o is an arc having a radius of curvature R ₁₇ _{having a center point O v3} at the left end of the ceiling portion 42e of the recess (42e, 43e), and the right end of the ceiling portion 42e of the recess. It is configured to be continuous with the envelope of an arc with a radius of curvature R ₁₈ = R ₁₇ having a center point O _{v4 at.}

R ₁₇ > R ₁₃ …… (3a)
R ₁₈ > R ₁₅ …… (3b)

Has a relationship. Therefore, the arc having the radius of curvature R _{15 and} _{the arc having the radius of curvature R 17} further extend outward on the left side as the curved surface of the peripheral region 36 _{Co where the curvature continuously changes.} Further, _{the arc having a radius of curvature R 16 and} the arc having a radius of curvature R ₁₈ extend outward on the right side as a curved surface of the peripheral region 36 _{Co where the curvature continuously changes.} The curved surface of the peripheral region 36C _o of the exit surface 36c is continuous with the curved surface of the central region 36C _{c as} a curved surface whose curvature continuously changes. As can be seen from FIG. 1B, _{the normal vector of the peripheral region 36C o} of the exit surface 36c and the normal vector of the central region 36C _c are different in direction and the center position of the radius of curvature thereof.

_{However, the positions of the center points O v1} , O _v2 , O _v3 , and O _v4 shown in Fig. 1B and the sizes of the radii of curvature R ₁₅ , R ₁₆ , R ₁₇ , and R ₁₈ are based on the design concept. It is merely an example schematically shown, and it goes without saying that different positions of center points, magnitudes of radius of curvature, and magnitude relationships are adopted in actual design. In particular, as the official Fresnel = selector represented by the formula (4) described later, the radius of curvature _{_{_{R 15, R 16, R 17}}} , R 18 size and the center point O _v1, O _v2, the O _v3, O _v4 The position and the like depend on the direction of the normal vector. The direction of the normal vector is determined by the angle of the tangent plane, and the angle of the tangent plane is determined by Snell's law with respect to the desired irradiation angle θ _illum . _{That is, the positions of the center points O v1} , O _v2 , O _v3 , and O _v4 shown in FIG. 1B are different from the positions of the center points used in the actual design determined by Snell's law.

In general, for actual design, the radius of curvature of an arc that defines the curvature _{of the peripheral region 36 Co o} _{and makes the magnitudes of radius R 15} , R ₁₆ , R ₁₇ , and R ₁₈ equal to the direction of the optical axis and the normal vector. It is preferably larger than R _0. In the top view of the bulk lens 1e of FIG. 1C, _{the boundary between the central region 36C c} and the peripheral region 36C _o is schematically shown by a two-dot chain line (virtual line) for convenience of explanation. However, since the exit surface 36c of the bulk lens 1e according to the first embodiment is a curved surface whose curvature changes continuously, a discontinuous line of curvature as shown by a two-dot chain line is actually a top view. It should be noted that it cannot be seen. Although it is not preferable because the design becomes difficult, an inflection point may be included in a part of the exit surface 36c as long as the curvature is continuous. An "inflection point" is defined for a curve such as the exit surface 36c that appears in the cross section of FIG. 1B, is second-order differentiable, has a continuous second-order derivative, but changes the sign of the second-order derivative. It is a point. The inflection point is the point where the angle of the tangent plane changes in the three-dimensional space. For example, an S-shaped curve such as a logistic curve or a Gombeltz curve may be included in the cross-sectional view.

As shown in FIG. 1B, the bulk type lens 1e according to the first embodiment passes through _{the incident point T 0} at the center of the ceiling portion 42e with respect to the light emitted from the center of the light emitting surface of the planar light emitting element 91e. The irradiation angle θ _{illum of the} light emitted from the first emission point E ₀ of the central region 36C _c _{of the emission surface 36c and the incident points T 13} and T ₁₄ of the ceiling portion 42e near the side wall 43e are passed through the central region 36C _c . _{2 The first emission point E 0} and the second emission points E ₁₃ and E ₁₄ _{so that the difference between the irradiation angles θ illum} of the light emitted from the emission points E ₁₃ and E _{14 is} within the first irradiation angle range of 10 degrees or less. The angle of the tangent plane with respect to the curved surface in is set. The “irradiation angle θ _illum ” is defined by the inclination of the light emitting surface of the planar light emitting element 91e from the normal direction. Since the normal direction of the light emitting surface passing through the center of the light emitting surface of the planar light emitting element 91e is the optical axis of the bulk lens 1e according to the first embodiment, the “irradiation angle θ _illum ” is the inclination angle from the optical axis. Is synonymous with. The "curvature vector" is obtained by differentiating the "tangent vector", and the "curvature" is the absolute value of the curvature vector. The curvature vector is a normal vector of the exit surface 36c at the exit point and is orthogonal to the tangent vector.

For the sake of simplicity, it is assumed that the three-dimensional structure of the bulk lens 1e is designed with the two-dimensional structure on the cross-sectional view shown in FIG. 1B. In the representation of the two-dimensional structure shown in FIG. 1B, the unit vector pointing to the tangential direction of the exit surface 36c is T, the unit vector pointing to the main normal direction of the exit surface 36c is N, and the unit vector pointing to the normal direction of the exit surface 36c is indicated. As is well known, assuming that the unit vector is B, the Frenet-Sele formula is expressed by the following equation (4).

In equation (4), d / ds represents the derivative of the arc length of the exit surface 36c, κ represents the curvature of the exit surface 36c, and τ represents the torsion of the exit surface 36c. The torsion of a curve corresponds to the spatial version of the curvature in the plane curve showing the exit surface 36c simplified in FIG. 1B.

The normal vector B is the outer product of the tangent vector T and the main normal vector:

B = T × N …… (5)

According to the Frenet-Serret formula, the irradiation angle θ _{illum of the} light emitted from the first emission point E _{0 in} _{the central region 36 C c} of the emission surface 36 c through _{the entrance point T 0} in the center of the ceiling portion 42e is close to the side wall 43e. The difference between the irradiation angles θ _illum of the light emitted from the second emission points E ₁₃ and E _{14 in} the central region 36 _{C c} _{through the incident points T 13} and T ₁₄ of the ceiling portion 42e is set to the first irradiation angle range within 10 degrees. This is to design the radius of curvature of the central region 36 _{C c} at the first exit point E ₀ and the second exit points E ₁₃ and E _14.

Further, it is incident from the incident points S ₁₁ and S ₁₂ _{on the uppermost side of the side wall 43e and reflected at the first reflection points B 11} and B ₁₂ on the rear outer wall surface 44e, and is reflected by the third emission point of the _{peripheral region 36C o of the emission surface 36c.} The irradiation angle θ _{illum of the} light emitted from E ₁₇ and E ₁₈ _{and the incident points S 13} and S _{14 at} positions away from the ceiling portion 42 e of the side wall 43 e are the second reflection points B _{13 of the rear outer wall surface 44 e.} as the difference in the irradiation angle theta _illum emitted from the fourth emission point E _15, E ₁₆ of the peripheral region 36C _o is reflected by B ₁₄ is the second irradiation angle range within 10 degrees, the third output point E The angle of the tangent plane with respect to the curved surface at ₁₇ , E ₁₈ and the fourth exit points E ₁₅ and E ₁₆ , and the tangent plane with respect to the rear reflection surface 44 at _{the first and second reflection points B 11} , B ₁₂ , B ₁₃ and B _14. And, if necessary, the inclination angle of the linear bus line forming the side wall 43e is set. Considering the Frenet-Serret formula, this means that the radius of curvature of the central region 36 _{C c} _{at the third exit points E 17} , E ₁₈ and the fourth exit points E ₁₅ , E ₁₆ and the first and second reflection points B ₁₁ , B ₁₂ , B ₁₃ and B ₁₄ will design the radius of curvature of the rear reflecting surface 44. Further, in the bulk type lens 1e according to the first embodiment, the first irradiation angle range and the second irradiation angle range are set to be the same.

As shown in FIG. 1A, the planar light emitting element 91e housed in the bulk lens 1e according to the first embodiment is mounted on the element mounting substrate 92e, and the element mounting substrate 92e is larger than the element mounting substrate 92e. It is mounted on the printed circuit board 93e of the area. The printed circuit board 93e is mounted on a metal plate 94e having a larger area than the printed circuit board 93e, and has a laminated structure of the printed circuit board 93e and the metal plate 94e. The bulk lens 1e according to the first embodiment is projected on the left side of the bulk lens 1e and is integrated with the optical transmission unit 39e of the bulk lens 1e on the first fixing scaffold 95e and on the right side of the bulk lens 1e. It has a second fixing scaffold 96e that protrudes and is integrated with the optical transmission unit 39e of the bulk lens 1e. The first fixing scaffold 95e and the second fixing scaffold 96e are connected between the rear outer wall surface 44e and the exit surface 36c, respectively.

The first fixing scaffold 95e and the second fixing scaffold 96e each have the shape of a quadrangular prism. If the first fixing scaffold 95e and the second fixing scaffold 96e are compared to both feet of an animal crocodile, the massive optical transmission unit 39e corresponding to the body of the crocodile is the first fixing scaffold 95e and the second fixing scaffold. It can be imitated as a floating structure supported by 96e. A cylindrical first through hole 97e penetrating in the column axis direction of the square pillar is opened in the center of the first fixing scaffold 95e, and a first through hole 97e is also formed in the center of the second fixing scaffold 96e. A cylindrical second through hole 98e that penetrates in parallel is opened. In the laminated structure of the printed circuit board 93e and the metal plate 94e, through holes are opened at two positions corresponding to the first through hole 97e and the second through hole 98e, respectively. A fixture such as a screw is passed through the through holes on the left side of the printed circuit board 93e and the metal plate 94e that are continuous with the first through holes 97e and the first through holes 97e, and are continuous with the second through holes 98e and the second through holes 98. By passing the fixture through the through hole on the right side of the printed circuit board 93e and the metal plate 94e, the bulk lens 1e is fixed to the metal plate 94e via the printed circuit board 93e.

FIG. 1D is a diagram for explaining the main light emitting portion of the planar light emitting element 91e, and shows an example of the configuration of an LED in which light is emitted from the upper surface. The planar light emitting device 91e illustrated in FIG. 1D includes, for example, a buffer layer 917 formed on a GaAs substrate 918, a spacer layer 916, an n-type contact layer 915, an n-type barrier layer 914, and an active layer 913. It includes a p-type barrier layer 912 and a p-type contact layer 911. The side portion from the upper surface of the p-type contact layer 911 to the vicinity of the center of the n-type contact layer 915 has been removed by means such as mesa etching, and n on the upper surface of the n-type contact layer 915 exposed thereby. The mold electrode 922 is provided with the p-type electrode 921 on the upper surface of the p-type contact layer 911, respectively.

In the planar light emitting element 91e configured as shown in FIG. 1D, the opening of the p-type electrode 921 on the upper surface of the p-type contact layer 911 forms a planar light emitting surface, and the optical path shown in FIGS. 1A and 1B. Lights of 66-1, 66-2, 66-3, 66-4, ... Are emitted from a large number (infinite number) of light emitting points defined on the light emitting surface. Explaining with the example shown in FIG. 1D, the light emitting surface exposed in the opening of the p-type electrode 921 is an example of the “main light emitting portion of the planar light emitting element 91e”, but is limited to the structure shown in FIG. 1D. It's not something. In the case of a white LED, a fluorescent agent is further applied or a layer of the fluorescent agent is formed on the light emitting surface exposed at the opening of the p-type electrode 921 in FIG. 1D. The upper surface of this fluorescent agent serves as a light emitting surface. In such a white LED, the portion of the upper end of the fluorescent agent and the container for storing the fluorescent agent, which surrounds the fluorescent agent as the light emitting surface in a frame shape, is "the main light emission of the planar light emitting element 91e". It is another example of "department".

If the ceiling portion 42e of the recesses (42e, 43e) of the bulk lens 1e has a convex lens shape, the light condensing property in the optical axis direction becomes high, and the light from the planar light emitting element 91e having a _{wider light emission angle θ rad.} _Can be emitted from the bulk lens 1e with a small irradiation angle θ illum. _{Light with a large emission angle θ rad} from the planar light emitting element 91e has a high reflectance at the ceiling portion 42e. Therefore, when the area of the light emitting surface of the planar light emitting element 91e is large, the influence of light whose light emitting point is a position deviated by a distance d from the central light emitting point is also large. On the other hand, if the ceiling of the recess of the conventional bulk lens is concave, light with a larger emission angle θ _rad of the planar light emitting element 91e is refracted in the direction of the emission surface of the bulk lens and incident. Can be done. However, only light with a _{narrower emission angle θ rad} from the planar light emitting element 91e can be emitted from the bulk lens with a small irradiation angle θ _illum.

Like the bulk lens 1e according to the first embodiment, _{light having a large emission angle θ rad} from the planar light emitting element 91e is incident from the side wall 43e of the recesses (42e, 43e) and is incident on the rear outer wall surface of the bulk lens 1e. It is reflected by 44e and emitted from the exit surface 36c of the bulk lens 1e. In the bulk type lens 1e of the type that is reflected by the rear outer wall surface 44e, almost all the light emitted from the planar light emitting element 91e _{can be emitted with a narrow irradiation angle θ illum} , so that the bulk type according to the first embodiment can be emitted. In the lens 1e, the side wall 43e of the concave portion preferably has a quadric curved surface having a straight generatrix, which is easy to design. The quadric surface (ruled surface) formed by all the generatrix parallel to a constant straight line passing through all the points on the curve forming the outer shape of the ceiling portion 42e of the recess is a pillar surface. The quadric surface (ruled surface) created by all the generatrix connecting all the points on the curve that form the outer shape of the ceiling portion 42e of the recess and the fixed points that are not on the ceiling portion 42e of the recess is a conical surface. be.

The recesses (42e, 43e) for accommodating the main light emitting portion are basically in the shape of a cylinder or a truncated cone as shown in FIGS. 7 and 10 described later. However, the cylindrical shape or the truncated cone is an example, and the present invention is not limited to the cylindrical shape or the truncated cone. For example, if you are willing to complicate the design, you may set the generatrix on the side of the cylinder to be non-straight. Alternatively, a modified example such as making the upper surface of a cylinder or a truncated cone into a curved surface having a large radius of curvature is also possible. In this way, it is possible to add various topologies to the basic shape of a cylinder or a truncated cone, but when deforming a cylinder or a truncated cone, if the deformation is a curved surface with a small radius of curvature, the optical path It should be noted that the design of the is difficult.

In order to facilitate the design of the bulk lens 1e according to the first embodiment, the side wall 43e of the recess may be composed of a plurality of planes having three or more planes. When the side wall 43e is composed of four planes, the recesses (42e, 43e) are rectangular parallelepipeds. When the number of a plurality of planes becomes a large number of planes of 20 or more, it approaches a cylindrical plane. The diameter of the rear outer wall surface 44d of the bulk lens 1e can be reduced when the side wall 43e of the recess has a large refraction angle on the incident surface. If the angle formed by the ceiling portion 42e and the side wall 43e of the recess is larger than 90 degrees, it becomes difficult to manufacture the bulk lens 1e according to the first embodiment with a mold. Therefore, in the bulk lens 1e according to the first embodiment, it is preferable that the direction of the linear bus line is substantially parallel to the optical axis and the recesses (42e, 43e) are cylindrical.

When the recesses (42e, 43e) are cylindrical, for example, the diameter of the ceiling portion 42e of the recess is 6 mm, the height of the side wall is 3 mm, the height from the ceiling portion 42e of the recess to the top of the exit surface 36 is 15 mm, and the surface shape. The distance from the light emitting surface of the light emitting element 91e to the ceiling portion 42e of the recess can be designed with a value of about 3 mm. As the optical medium that connects the exit surface 36c and the rear outer wall surface 44e, for example, an optical acrylic resin can be adopted. However, the optical medium may be any transparent medium. For example, polycarbonate has excellent heat resistance, and glass has excellent heat resistance and reliability. Therefore, polycarbonate, glass, and the like are also suitable materials as an optical medium for the bulk lens 1e according to the first embodiment. As described above, according to the bulk type lens and the light emitting body according to the first embodiment, it is possible to efficiently use the size of the light emitting surface of the planar light emitting element having a large area of the light emitting surface, and from the central light emitting point. Compact that reduces the influence of light emitted from a position such as a distant end emission point, increases the light collection efficiency with a narrow irradiation angle, and efficiently illuminates a wide irradiation area with a light intensity distribution with excellent uniformity. Structure can be provided.

= Bulk type lens design method according to the first embodiment =
With respect to the light emitted from the center of the light emitting surface of the planar light emitting element 91e, the light emitted from the first emission point E _{0 in} _{the central region 36 C c} of the exit surface 36 c through _{the incident point T 0 in the center of the ceiling portion 42e.} an irradiation angle theta _illum of the difference in the irradiation angle theta _illum of the light emitted from the second emitting point E _13, E ₁₄ in the central region 36C _c through an incident point T _13, T ₁₄ of the ceiling portion 42e close to the side wall 43e In order to make the first irradiation angle range within 10 degrees, the first exit point E ₀ and the second exit point E _{13 by geometrical optical drawing and automatic design using an optical simulator, etc.} The angle of the tangent plane with respect to the curved surface at E _{14 may be determined.} For example, it is possible to determine the angle of the tangent plane by various methods such as a heuristic method in which drawing using geometrical optics is tried and errored, and an optical simulator in which fluctuations are applied by a quantum computer.

Further, the light emitted from the third emission points E ₁₇ and E ₁₈ _{of the peripheral region 36 Co o} _{of the emission surface 36c, which is incident from the incident points S 11} and S ₁₂ on the uppermost side of the side wall 43e and reflected by the rear outer wall surface 44e. an irradiation angle theta _illum, fourth emission points in the peripheral region 36C _o light incident from the incident point S _13, S ₁₄ of a position away from the ceiling portion 42e is reflected by the rear outer wall surface 44e of the side wall 43e E _15, E _It is also possible to make the difference between the irradiation angles θ _illum emitted from 16 within the second irradiation angle range within 10 degrees by using geometrical optics drawing and an optical simulator to use the third emission points E ₁₇ , E ₁₈ and Design the angle of the tangent plane with respect to the curved surface at the fourth exit points E ₁₅ and E ₁₆ and the angle of the tangent plane _{of the rear reflection surface 44 at the first and second reflection points B 11} , B ₁₂ , B ₁₃ and B _14. do it. In some cases, the inclination angle of the linear bus forming the side wall 43e may be designed, if necessary.

For example, as shown in the flowchart of FIG. 1E, first, in step S101, the exit surface 36c, the optical transmission unit 39e in contact with the emission surface 36c, the rear outer wall surface 44e in contact with the optical transmission unit 39e, and the optical transmission unit 39e. The initial design outline of the structure is drawn, which is composed of a ceiling portion 42e provided inside the above and a side wall 43e connected to the ceiling portion 42e, and has recesses (42e, 43e) for accommodating the main light emitting portion. In the flowchart of FIG. 1E, for simplification, the ceiling portion 42e and the side wall 43e of the recesses (42e, 43e) are orthogonal to each other, and the angle formed by the generatrix of the side wall 43e with the ceiling portion 42e is fixed. When the step of changing the angle formed by the bus of the side wall 43e omitted from the flowchart of FIG. 1E with the ceiling portion 42e is added, the degree of freedom in design is increased, but the manufacturing process is complicated as described above. Next, in step S102, the numerical values of the first irradiation angle range and the second irradiation angle range are input. It is desirable that the values of the first irradiation angle range and the second irradiation angle range are substantially the same as each other, but there may be a difference of 2 to 5 degrees depending on the conditions required for the design specifications. Next, in step S103, the planar light emitting element 91e is inserted into the concave portion (42e, 43e), and the relative position between the concave portion (42e, 43e) and the planar light emitting element 91e is determined.

When the relative positions of the recesses (42e, 43e) and the planar light emitting element 91e are determined in step S103, in step S104, the incident points T ₀ , T ₁₁ , T ₁₂ , T ₁₃ , T ₁₄ and the ceiling portion 42e are determined. input position of the incident point of the side wall _{_{43e S 11, S 12, S}} 13, S 14 into the recess (42e, 43e) are determined. _{Further, of the first reflection points B 11} and B _{12 which} are _{incident from the incident points S 11} and S ₁₂ on the uppermost side of the side wall 43e, reach the rear outer wall surface 44e, and are the starting points of the light reflected by the rear outer wall surface 44e. Determine the position. Step In S104, at the same time, light incident from the incident point S _13, S ₁₄ of a position away from the ceiling portion 42e reaches the rear outer wall surface 44e, a second reflection as a starting point of the light reflected by the rear outer wall surface 44e The positions of points B ₁₃ and B _{14 are determined.} Thereafter, in step S105, so that the light reflected by the first reflection point B _11, B _12, and the light reflected by the second reflection point B _13, B _14, and reaches the peripheral region 36C _o both, the first and The curvature of the rear reflection surface 44 at the second reflection points B ₁₁ , B ₁₂ , B ₁₃ , and B _{14 is determined, respectively.} To "determine the curvature" in step S105 is to mathematically determine the radius of curvature, or to the rear reflection plane 44 at _{the first and second reflection points B 11} , B ₁₂ , B ₁₃ , and B _14. Equivalent to determining the angle of the tangent plane.

Then, in step S106, the irradiation angle theta _illum of the light emitted from the first emitting point E _0, the difference in illumination angle theta _illum of the light emitted from the second emitting point E _13, E ₁₄ is within 10 degrees first Using Snell's law, the curvature of the central region 36 _{C c} _{at the first exit point E 0} and the second exit points E ₁₃ and E ₁₄ is determined so as to be within the irradiation angle range. "Determining the curvature" of the central region 36C _{c in} step S106 is mathematically equivalent to determining the radius of curvature and determining the angle of the tangent plane of the _{central region 36C c.} It should be noted that determining the curvature of the central region 36C _c _{at the first exit point E 0} and the second exit points E ₁₃ and E ₁₄ using Snell's law means that the curvature is a function of the refractive index, so that light is used. Irregular impurities are added to the optical medium constituting the transmission unit 39e to form a refractive index distribution inside the optical transmission unit 39e, and the irradiation angle θ _illum is controlled by the effect of the refractive index distribution. May be good. Further, in step S107, the difference between the irradiation angles θ _illum _{of the light emitted from the third emission points E 17} and E ₁₈ and the irradiation angles θ _illum emitted from the fourth emission points E ₁₅ and E ₁₆ is within 10 degrees. so that the irradiation angle range by using the Snell's law to determine the curvature of the peripheral region 36C _o in the third emission point E _17, E _18, and fourth emission points E _15, E _16.

Incidentally, by using the Snell's law, that determines the curvature of the peripheral region 36C _o in the third emission point E _17, E _18, and fourth emission points E _15, E ₁₆ constitute the optical transmission section 39e optical An impurity may be added to the medium non-uniformly to form a refractive index distribution inside the optical transmission unit 39e, and the irradiation angle θ _illum may be controlled by the effect of the refractive index distribution. "Determining the curvature" of the peripheral region 36C _{o in} step S107 is mathematically equivalent to determining the radius of curvature and determining the angle of the tangent plane of the _{peripheral region 36C o.}

Then, in step S108, it is confirmed whether or not the curvature of _{the central region 36C c} determined in step S106 and the curvature of the peripheral region 36C _{o determined in step S107 are continuous.} If the curvature of the central region 36C _{c and} the curvature of the peripheral region 36C _o are not continuous, return to step S105 via step S111 and rearward at _{the first and second reflection points B 11} , B ₁₂ , B ₁₃ , and B _14. An alternative for the reflective surface 44 is determined, and this alternative is searched for an alternative for the curvature of _{the central region 36C c} in step S106 and the curvature of the peripheral region 36C _{o in step S107.} The loop of step S108 → step S111 → step S115 is repeated until the curvature _{of the central region 36C c and} the curvature of the peripheral region 36C _{o become continuous.}

However, if the condition that the curvature _{of the central region 36C c and} the curvature of the peripheral region 36C _o are continuous is not confirmed in step S108 even if the loop processing of step S108 → step S111 → step S115 is repeated a certain number of times, step S112 is performed. The process returns to step S103. That is, in step S111, it is counted whether the number of loop processes of step S108 → step S111 → step S105 has reached the preset maximum number of _{repeats N max1 and} has reached the maximum number of _repeats N max1. If it is determined, the process returns to step S103 by a new branch loop. Then, in step S103, a new relative position between the recesses (42e, 43e) and the planar light emitting element 91e is determined as an alternative, and the processes of step S103 → step S104 → step S105 → step S106 → step S107 → step S108 are performed. repeat.

_{If the condition that the curvature of the central region 36C c and} the curvature of the peripheral region 36C _o are continuous is not confirmed in step S108 even if the loop processing of step S108 → step S111 → step S112 → step S103 is repeated a certain number of times, step S108. The process returns to step S102 via S112. That is, in step S112, it is counted whether the number of loop processes of step S108 → step S111 → → step S112 → step S103 has reached the preset second maximum number N _max2 , and the second maximum number N _When it is determined that max2 has been reached, the process returns to step S102 by a new branch loop. In step S102, the numerical values of the first irradiation angle range and the second irradiation angle range may be re-entered within 10 degrees. In step S102, when the values of the first irradiation angle range and the second irradiation angle range are first input as strict values such as within 3 degrees, the _{curvature of the central region 36C c} and the peripheral region 36C even if the loop processing is repeated. _{The curvature of o} may not be continuous. In such a case, in step S102, the numerical values of the first irradiation angle range and the second irradiation angle range may be reset to more gradual values within 10 degrees.

Further, when the values of the first irradiation angle range and the second irradiation angle range are set to be completely the same, the _{curvature of the central region 36C c} and the peripheral region 36C _{o in step S108 even if the loop processing is repeated many times.} There is a high possibility that the curvatures of will not be continuous. In such a case, in step S102, the degree of coincidence between the values of the first irradiation angle range and the second irradiation angle range may be relaxed so that there is a gentle condition, for example, a difference of 2 to 5 degrees. That is, in the design of the bulk lens 1e according to the first embodiment, "the first irradiation angle range and the second irradiation angle range are the same" means that 2 is between the first irradiation angle range and the second irradiation angle range. It means to include the case of "substantially the same" or "equal to the same" such as a condition including a difference of ~ 5 degrees. _{If the curvature of the central region 36C c and} the curvature of the peripheral region 36C _o are not continuous in step S108 under the condition of a uniform refractive index distribution, the refractive index distribution of the transmission unit 39e is adjusted to be non-uniform. There is also a method. That is, since Snell's law depends on the refractive index, a distribution of the refractive index is formed inside the optical transmission unit 39e by locally adding impurities to a specific region of the optical medium, and the irradiation angle θ _illum. May be adjusted. When it is confirmed in step S108 that the curvature of the central region 36C _{c and} the curvature of the peripheral region 36C _o are continuous, in step S109, a structure other than the massive optical transmission unit 39e surrounded by the exit surface 36c and the rear outer wall surface 44e. Is determined, the design of the bulk lens 1e according to the first embodiment is completed. As described above, according to the bulk type lens design method according to the first embodiment, it is possible to efficiently use the size of the light emitting surface of the planar light emitting element having a large area of the light emitting surface, and from the central light emitting point. Compact that reduces the influence of light emitted from a position such as a distant end emission point, increases the light collection efficiency with a narrow irradiation angle, and efficiently illuminates a wide irradiation area with a light intensity distribution with excellent uniformity. The structure can be designed.

= Example of optical design of bulk lens according to the first embodiment =
As described above, the first irradiation angle range and the second irradiation angle range may be within 10 degrees, but as a more preferable example, the case where the first irradiation angle range and the second irradiation angle range are within 8 degrees is used. , An example of designing the bulk lens 1e according to the first embodiment will be described below. As described above, an embodiment will be described by defining the normal direction of the light emitting surface passing through the center of the light emitting surface of the planar light emitting element 91e as the “optical axis” of the bulk lens 1e. As described above, assuming that the diameter of the ceiling portion 42e of the recess is 6 mm, the height of the side wall is 3 mm, and the distance from the light emitting surface of the planar light emitting element 91e to the ceiling portion 42e is 3 mm, the surface shape is located on the optical axis. _{Light within a light emitting angle θ rad} = about ± 45 degrees from a light emitting point located at the center (center point) of the light emitting surface of the light emitting element 91e (hereinafter, simply abbreviated as “center light emitting point”) is shown in FIG. 1B. As described above, the light is incident from the incident points T ₀ , T ₁₁ , T ₁₂ , T ₁₃ and T ₁₄ of the ceiling portion 42e. Here, it is assumed that the “emission angle θ _rad ” is measured with reference to the normal direction of the light emitting surface of the planar light emitting element 91e, similarly to the irradiation angle θ _illum. Further, as shown in FIG. 1B, the light having _{an emission angle θ rad} = about ± 45 degrees or more from the central emission point _{is incident from the incident points S 11} , S ₁₂ , S ₁₃ and S ₁₄ on the side wall 43e. Light incident from incident points T ₀ , T ₁₁ , T ₁₂ , T ₁₃ and T ₁₄ _{is emitted from the central region 36 C} c of the exit surface 36 c, and is incident from incident points S ₁₁ , S ₁₂ , S ₁₃ and S _14. Is reflected by the rear outer wall surface 44e and is emitted from _{the peripheral region 36C o of the exit surface 36c.}

As shown as an optical path 66-1 in FIGS. 1A and 1B, the light emitted from the central emission point at an emission angle θ _rad = about 0 degrees is emitted from the emission surface 36c of the bulk lens 1e at an irradiation angle θ _illum =. It emits at 0 degrees. Although the angle is not specified in FIGS. 1A and 1B, according to the procedure shown in FIG. 1E, the emission angle is θ _rad, which is smaller than 45 degrees but relatively close to 45 degrees, from the ceiling portion 42e of the recess. The shape of the exit surface 36c of the bulk lens 1e can be designed so that _{the irradiation angle θ illum} from the bulk lens 1e of the incident light is about 8 degrees. On the other hand, from the central light emitting point, the light _{incident from the side wall 43e of the recess at an emission angle θ rad} larger than 45 degrees but relatively close to 45 degrees and reflected by the rear outer wall surface 44e of the bulk lens 1e is transmitted from the bulk lens 1e. The shape of the exit surface 36c of the bulk lens 1e and the rear outer wall surface 44e of the bulk lens 1e can be designed so that the irradiation angle θ _{illum of the bulk lens 1e is about 0 degrees.} Further, the bulk type lens 1e of the light incident from the side wall 43e of the recess and reflected by the rear outer wall surface 44e of the bulk type lens 1e at a _{large light emitting angle θ rad} smaller than 90 degrees from the central light emitting point but relatively close to 90 degrees. The shape of the exit surface 36c of the bulk lens 1e and the rear outer wall surface 44e of the bulk lens 1e can be designed so that the irradiation angle θ _{illum from the lens 1e is about 8 degrees.}

The light emitted from the central light emitting point incident from the ceiling 42e at an emission angle θ _rad = about 0 to 45 degrees has an irradiation angle θ _illum from the bulk lens 1e in the range of about 0 degrees to about 8 degrees. It is changing gradually. The light emitted from the planar light emitting element 91e at an emission angle θ _rad = about 45 to about 90 degrees is _{the optical path incident from the incident points S 11} and S ₁₂ near the ceiling portion 42e and the incident point far from the ceiling portion 42e. an optical path incident S _13, S ₁₄ Karakara is, the position of the exit point in the peripheral region 36C _o has reversed with respect to the distance from the optical axis. In the peripheral region 36C _o, has a fourth output point E _15, E ₁₆ close to the position of the optical axis, the light emitting angle theta _rad is light close to 90 degrees less than about 90 degrees. In FIG. 1B, the irradiation angle θ _{illum of the} _{light emitted from the fourth emission points E 15} and E ₁₆ is about 8 degrees. Although the emission angle θ _rad is larger than 45 degrees, _{the positions of the third emission points E 17} and E ₁₈ where the light incident from the side wall 43e is emitted at the _{emission angle θ rad} relatively close to about 45 degrees are farthest from the optical axis. ing. The irradiation angle θ _{illum of the} light emitted from the third emission points E ₁₇ and E ₁₈ is about 0 degrees. Therefore, as can be seen from FIGS. 1A and 1B, even for the light emitted from the planar light emitting element 91e at an emission angle θ _rad = about 45 to about 90 degrees, the irradiation angle θ _{illum from the peripheral region 36 Co} _{o is} about. It gradually changes in the range from 8 degrees to 0 degrees.

_{When the irradiation angle θ illum} from the conventional bulk lens increases, the light emitted from the conventional bulk lens containing the surface light emitting LED has a cosine function of the irradiation angle θ _illum , and the irradiation light intensity decreases. Further, it is inversely proportional to the square of the distance between the conventional bulk lens containing the surface light emitting LED and the irradiation position. Therefore, in order for the light emitted from the conventional bulk lens to have a uniform illuminance distribution, it is necessary to correct the intensity distribution of the irradiation light. For example, if the ratio of the change in the _{irradiation angle θ illum} of the conventional bulk type lens _{to the emission angle θ rad} from the light emitting surface of the surface light emitting LED is reduced by approximately proportional to the cosine function of _{the emission angle θ rad from the light emitting surface.} , The illuminance distribution from the conventional bulk type lens becomes more uniform.

With a conventional bulk lens with an irradiation angle of θ _illum = ± 10 degrees, the emission angle from the light emitting surface is θ _rad = 0 degrees, 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees. When the degree changes to 45 degrees, the change in the irradiation angle θ _illum of the light from the corresponding conventional bulk lens can be made substantially proportional to the cosine function of _{the emission angle θ rad} from the light emitting surface. When approximately proportional to the cosine function of the emission angle θ _rad _{, the irradiation angles θ illum} from a conventional bulk lens = 0 degrees, 1.3 degrees, 2.5 degrees, 3.7 degrees, 4.9 degrees, 6 It becomes 0.0 degree, 7.1 degree, 8.2 degree, 9.1 degree, 10 degree, respectively. According to the bulk type lens 1e according to the first embodiment, the irradiation angle θ _illum from the bulk type lens 1e according to the first embodiment is corrected by the same method as the correction example for the conventional bulk type lens. There is.

In this way, the light incident from the ceiling portion 42e near the side wall 43e is _reflected by the irradiation angle θ _{illum1 emitted from the central region 36C c,} and the light incident from the side wall 43e located away from the ceiling portion 42e is reflected by the rear outer wall surface 44e. Assuming that the irradiation angle θ _{illum 2} emitted from the peripheral region 36C _o _{is approximately the same angle, the portion of the central region 36C c} through which the light incident from the ceiling portion 42e passes _{and the portion of the peripheral region 36C o} through which the light incident from the side wall 43e passes The shape can be smoothly connected. Further, light with an emission angle θ _rad = about 0 to 45 degrees is irradiated with light with an irradiation angle θ _illum = 0 to 8 degrees within the range of the first irradiation angle, and light with an emission angle θ _rad = about 45 to about 90 degrees is second irradiated. _{Since the light is emitted at an irradiation angle θ illum} within the angle range of 0 to 8 degrees and the first irradiation angle range and the second irradiation angle range overlap, the irradiation angle θ _illum of the bulk lens 1e and the design of the light intensity distribution can be designed. It's easy.

According to the bulk type lens 1e according to the first embodiment, the emission angles θ _rad from the light emitting surface are 0 degrees, 10 degrees, 20 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees, and 80 degrees. In the case, each irradiation angle θ _illum can be designed to be about 0 degree, 2 degree, 4 degree, 5.5 degree, 7 degree, 2 degree, 4.5 degree, 7 degree and 8 degree. According to the bulk type lens 1e according to the first embodiment, all the reflections on the rear outer wall surface 44e are under the total reflection condition, but if the total reflection condition is not satisfied, a specular reflection treatment is required. Further, in a bulk type lens that utilizes the reflection of the rear outer wall surface 44d such as the bulk type lens 1e according to the first embodiment, the positions of the optical axis and the height of the planar light emitting element 91e and the bulk type lens 1e are aligned. Difficult to fix. However, the bulk lens 1e according to the first embodiment is provided with a first fixing scaffold 95e and a second fixing scaffold 96e integrated with the optical transmission unit 39e. Since the first through hole 97e is opened in the first fixing scaffold 95e and the second through hole 98e is opened in the second fixing scaffold 96e, the position of the design condition is determined by using the fixing screw. The bulk type lens 1e can be easily fixed.

= Light emission at a position deviated from the central light emission point =
FIG. 2 shows the locus of an optical path when the light emitting point is a position deviated from the central light emitting point of the planar light emitting element 91e by a distance d in the bulk type lens 1e according to the first embodiment. Assuming that a general 3W class planar LED for illumination is a planar light emitting element 91e, the light whose emission point is located at a position deviated by a distance d from the central light emitting point has a maximum deviation distance d _max = ± 0.8 mm. In this case, the irradiation angle θ _illum is widened by about 3 degrees on one side. _{Since the one-sided irradiation angle range Δθ illum} = ± 8 degrees in the case of the optical axis upper surface light emitting element 91e of the bulk type lens 1e according to the first embodiment can be designed, a 3W class planar LED for illumination can be used as a planar light emitting element. _{Assuming that} the one-sided irradiation angle range Δ illum = about ± 11 degrees when mounted as 91e, the bilateral spread width of the irradiation angle is expected to be about 22 degrees.

With reference to FIG. 2, in the bulk lens 1e according to the first embodiment, an optical path in the case where a position deviated from the central light emitting point of the planar light emitting element 91e by a distance d is used as the light emitting point will be examined. In the bulk lens 1e according to the first embodiment, the light emitted from the light emitting point at the position of the left end portion deviated from the central light emitting point by a distance d = −0.8 mm is the ceiling adopted in the above embodiment. Under the boundary conditions of the diameter of the portion 42e = 6 mm, the height of the side wall = 3 mm, and the distance from the light emitting surface to the ceiling portion 42e = 3 mm, the emission angle θ _rad = −35 to +50 from the left end of the planar light emitting element 91e. As shown in FIG. 2, the light emitted in degrees is incident on the bulk lens 1e from the ceiling portion 42e.

Meanwhile, light emitted by the light emitting angle θ _rad = + 50 or more large light emitting angle theta _rad from the light emitting point of the left end portion of the planar light-emitting element 91e, as shown in FIG. 2, the bulk lens from the right side wall 43e It is incident on 1e. The light emitted from the light emitting point at the left end of the planar light emitting element 91e at a large light emitting angle θ _rad _{having a light emitting angle θ rad} = −35 or more is incident on the bulk lens 1e from the left side wall 43e. From the emission point at the left end, the emission angle θ _rad = -80 degrees, -70 degrees, -60 degrees, -50 degrees, -40 degrees, -30 degrees, -20 degrees, -10 degrees, 0 degrees, +10 degrees, Irradiation angles of light emitted at +20 degrees, +30 degrees, +40 degrees, +50 degrees, +60 degrees, +70 degrees, +80 degrees _{θ illum = about -12.5 degrees, -12 degrees, -12 degrees, -8.5} Degrees, -4 degrees, -2 degrees, -0.5 degrees, 1 degree, 3 degrees, 5 degrees, 7 degrees, 9 degrees, 10.5 degrees, 12 degrees, -1 degree, +0.5 degrees, +3. It will be 5 degrees.

As shown in FIG. 2, in the light whose emission point is a position deviated by a distance d from the central emission point, the irradiation angle θ _illum spreads by about ± 4 degrees on both sides due to the influence of the deviation d = ± 0.8 mm. Therefore, in the bulk lens 1e according to the first embodiment, the light whose emission point is a position deviated by a distance d from the central emission point has a one-sided irradiation angle range Δθ _illum = about ± 12 degrees, and the irradiation angle as a whole. The width of the spread on both sides is about 24 degrees. _{The irradiation angle range Δθ illum} by light whose emission point is a position deviated by a distance d from the central emission point is large for light having a large _{emission angle θ rad} from the planar light emitting element 91e. However, according to the bulk type lens 1e according to the first embodiment, the position deviated by the distance d from the central light emitting point is emitted by the optimized design of the curvatures of _{the rear outer wall surface 44d, the central region 36C c} and the peripheral region 36C _o. It can be estimated that the irradiation light from the light as a point _{can be brought close to the one-sided irradiation angle range Δθ illum = ± 3 degrees.}

(Second Embodiment)
As shown in FIG. 3, the bulk type lens 1f according to the second embodiment of the present invention is a bulk type lens 1f that houses a main light emitting portion of a planar light emitting element 91f such as an LED. Similar to the bulk lens 1e according to the first embodiment, the bulk lens 1f according to the second embodiment has an exit surface 36f formed of a curved surface whose curvature continuously changes and an optical medium in contact with the exit surface 36f. It is composed of a bulk-shaped optical transmission unit 39f, a rear outer wall surface 44f in contact with the optical transmission unit 39f, a ceiling portion 42f provided inside the optical transmission unit 39f, and a side wall 43f connected to the ceiling portion 42f. , It is provided with recesses (42f, 43f) for accommodating the main light emitting portion. The shape of the exit surface 36f is designed so that all the light emitted from the light emitting point on the optical axis of the planar light emitting element 91f _{is focused at an irradiation angle θ illum} = 0 degrees, that is, all the light is focused in the optical axis direction. ing. As the optical medium used for the bulk lens 1f according to the second embodiment, various transparent materials such as an optical acrylic resin, polycarbonate, and glass as described for the bulk lens 1e according to the first embodiment can be used. be.

As shown in FIG. 3, the planar light emitting element 91f is mounted on the element mounting substrate 92f, the element mounting substrate 92f is mounted on the printed circuit board 93f, and the printed circuit board 93f is mounted on the metal plate 94f. There is. The bulk lens 1f according to the second embodiment has a first fixing scaffold 95f protruding to the left and integrated with an optical transmission unit 39f of the bulk lens 1f, and an optical transmission unit of the bulk lens 1f protruding to the right. It has a second fixing scaffold 96f integrated with 39f. A first through hole 97f is opened in the first fixing scaffold 95f, and a second through hole 98f is opened in the second fixing scaffold 96f. By passing the fixture through the first through hole 97f and the first through hole 97f, the bulk lens 1f is fixed to the metal plate 94f via the printed circuit board 93f.

Also in the bulk lens 1f according to the second embodiment, the normal direction of the light emitting surface passing through the center of the light emitting surface of the planar light emitting element 91f is defined as the “optical axis” of the bulk lens 1f according to the second embodiment. Is defined as. For example, the ceiling portion 42f of the recesses (42f, 43f) of the bulk lens 1f has a diameter of 6 mm and is flat, and the side wall 43f has a height of 3 mm. It can be adopted. The distance from the light emitting surface of the planar light emitting element 91f to the ceiling portion 42f is, for example, 3 mm, and the same dimensions as those of the bulk type lens 1e according to the first embodiment can be adopted.

_{Light with an emission angle θ rad} = about ± 45 degrees or less from the central emission point defined at the center of the emission surface of the planar light emitting element 91f is incident from the ceiling portion 42f to the optical transmission portion 39f of the bulk lens 1f. It emits light from the central region of the exit surface 36f. On the other hand, light having an emission angle of θ _rad = about ± 45 degrees or more is incident on the optical transmission unit 39f from the side wall 43f, reflected by the rear outer wall surface 44f, and emitted from the peripheral region of the exit surface 36f. In the description of the bulk lens 1f according to the second embodiment, the case where the rear outer wall surface 44f can be designed under the total reflection condition will be described for convenience, but the present invention is not limited to the total reflection condition. If the total reflection conditions are not met due to conditions such as the light emission characteristics of the light emitting surface of the planar light emitting element 91f and the outer shape of the optical transmission unit 39f, a specular reflection treatment such as a metal film having high reflectance is performed on the rear outer wall surface 44f. The structure may be used. FIG. 3 shows how the light emitted from the central emission point at an emission angle θ _rad = about 0 degrees is emitted from the emission surface 36f via the optical path 68-1 at an irradiation angle θ _illum = 0 degrees. ing.

Light incident from the ceiling 42f at an _{emission angle θ rad} that is smaller than 45 degrees but relatively close to 45 degrees from the central emission point is emitted from the emission surface so that _{the irradiation angle θ illum from the bulk lens 1f is about 0 degrees.} The shape of 36f is designed. Light that is larger than 45 degrees from the light emitting surface of the planar light emitting element 91f but has a light emitting angle θ _rad = about 45 degrees is incident from the side wall 43f, and the light reflected by the rear outer wall surface 44f is emitted from the emitting surface 36f. The shape of the exit surface 36f is designed so that the light is emitted at an angle θ _{illum = about 0 degrees.} _{At a large emission angle θ rad,} which is smaller than 90 degrees from the light emitting surface but relatively close to 90 degrees, the light incident from the side wall 43f and reflected by the rear outer wall surface 44f is emitted from the emission surface 36f at an irradiation angle θ _illum = about 0. The shape of the exit surface 36f is designed so that it emits in degrees.

_{In the bulk type lens 1f according to the second embodiment, the irradiation angle θ illum} at which the light incident from the ceiling portion 42f near the side wall 43f is emitted from the central region of the exit surface 36f and the side wall 43f at a position away from the ceiling portion 42f. _{The irradiation angle θ illum} that the light incident from is reflected by the rear outer wall surface 44f and emitted from the peripheral region of the exit surface 36f is the same angle. Therefore, according to the bulk type lens 1f according to the second embodiment, the central region of the exit surface 36f through which the light incident from the ceiling portion 42f passes and the peripheral region of the exit surface 36f through which the light incident from the side wall 43f pass are formed. The shape can be smoothly connected.

An optical path in the case where the position of the end portion of the bulk lens 1f according to the second embodiment deviated by a distance d from the central light emitting point of the planar light emitting element 91f is used as the light emitting point (hereinafter referred to as “end light emitting point”). The locus of is shown in FIG. The diameter of the equivalent light emitting surface of a general 3W class planar LED for illumination = about 1.6 mm. The light emitted from the end light emitting point shifted by a distance d = -0.8 mm from the central light emitting point of this 3W class illumination planar LED has an irradiation angle θ _illum = as shown in the optical path 69-1. The light is emitted from the central region of the exit surface 36f at about +3.5 degrees. That is, the light emitted from the end light emitting point has a deviation d = ± 0.8 mm, so that the irradiation angle θ _illum = about ± 3.5 degrees spreads.

In the bulk lens 1f according to the second embodiment, a field having a light emitting point on the optical axis can be designed with _{an irradiation angle θ illum = 0 degrees.} _{However, it is expected that} the irradiation angle θ illum = about ± 3.5 degrees and the width of the emitted light = about 7 degrees when a 3W class planar LED that is contributed by radiation from a light emitting point located outside the optical axis is mounted. Will be done. In the bulk type lens 1f according to the second embodiment, in the case of the light emitted from the end emission point of d = 0.8 mm, the light _{emitted within the emission angle θ rad} = −35 to +50 degrees is the ceiling portion 42f. Is incident on the bulk lens 1f. Light of large emission angle θ _rad = -35 ~ + 50 ° emission angle θ _rad = -35 ~ + 50 ° or more is incident from the side wall 43f to the bulk lens 1f.

Emission angle θ _rad = -80 degrees, -70 degrees, -60 degrees, -50 degrees, -40 degrees, -30 degrees, -20 degrees, -10 degrees, 0 degrees, +10 degrees, +20 degrees, +30 degrees, +40 _{The light emitted at +50} degrees, +60 degrees, +70 degrees, and +80 degrees has an irradiation angle of θ illum = about -5.5 degrees, -8 degrees, -8 degrees, -6 degrees, and -4.5 degrees, respectively. 5, 4.5 degrees, 3.5 degrees, 3.5 degrees, 3.5 degrees, 3.5 degrees, 4 degrees, 5 degrees, 5.5 degrees, -6 degrees, -8 degrees, -13 It becomes a degree. The light emitted from the end emission point deviated by the distance d is about ± 5 degrees for light with a small _{emission angle θ rad} due to the effect of deviation d = ± 0.8 mm, and is maximum for light with a large _{emission angle θ rad.} The irradiation angle θ _illum became wider by about ± 8 degrees. _{The spread of the irradiation angle θ illum} due to the light emitted from the end emission point deviated by the distance d becomes large with the light having _{the emission angle θ rad} from the planar light emitting element 91f. However, due to the optimized design of the shapes of the rear outer wall surface 44d and the exit surface 36f, _{the spread of the irradiation angle θ illum} due to the light emitted from the end emission point deviated by the distance d can be brought close to ± 3.5 degrees. It is possible.

Although a duplicate description will be omitted, the bulk lens according to the second embodiment can be designed by the same procedure as the flowchart shown in FIG. 1E. According to the method for designing the bulk lens, the light emitter, and the bulk lens according to the second embodiment, it is possible to efficiently use the size of the light emitting surface of the planar light emitting element having a large light emitting surface area, and it is compact. Light intensity distribution with excellent uniformity over a wide irradiation area, reducing the influence of light emitted from positions such as the end light emitting point away from the central light emitting point, and increasing the light collection efficiency at a narrow irradiation angle. Can be illuminated efficiently.

(Third Embodiment)
As shown in FIGS. 5 and 6, the bulk lens 1g according to the third embodiment of the present invention is a bulk lens 1g that houses the main light emitting portion of 91 g of a planar light emitting element such as an LFD. Similar to the bulk lens 1f according to the first and second embodiments, the bulk lens 1g according to the third embodiment has an exit surface 36g formed of a curved surface whose curvature continuously changes and the exit surface 36g. An asymmetric bulk optical transmission unit 39g made of an optical medium in contact, a rear outer wall surface 44g in contact with the optical transmission unit 39g, a ceiling portion 42g provided inside the optical transmission unit 39g, and a side wall connected to the ceiling portion 42g. It is composed of 43 g and has recesses (42 g, 43 g) for accommodating the main light emitting portion. The "asymmetric bulk shape" has an asymmetric topology with respect to the optical axis, as can be seen from the comparison between FIGS. 5 and 6. Here, the "optical axis" refers to the light emitting surface of the planar light emitting element 91 g housed inside the recesses (42 g, 43 g), as in the definition of the bulk lens 1f according to the first and second embodiments. This is the center line of the optical transmission unit 39g that passes through the center and is in the normal direction of the light emitting surface. As the optical medium used for the bulk lens 1g according to the third embodiment, various transparent materials typified by an optical acrylic resin or the like as described in the bulk lens 1e according to the first embodiment can be used. ..

The optical structure of the bulk lens 1g according to the third embodiment will be described in the XYZ coordinate system including the X-axis and the Y-axis orthogonal to the Z-axis, where the optical axis defined as described above is the Z-axis. do. That is, the locus of the optical path in the 1g cross section of the bulk lens in the X-axis direction of Y = 0 is shown in FIG. 5, and the locus of the optical path in the cross section of the bulk lens 1g in the Y-axis direction of X = 0 is shown in FIG. Assuming that the bulk lens 1g according to the third embodiment has a length of 15 mm on the optical axis, the following dimensions can be exemplified. However, the ceiling portion 42g is a flat surface, and in the cross-sectional views of FIGS. 5 and 6, the side wall having the direction of the linear generatrix orthogonal to the ceiling portion 42g is a cylindrical surface. Under such an assumption, a bulk type lens 1 g can be designed with dimensions such as a ceiling portion 42 g having a diameter of 6 mm and a side wall 43 g having a height of 3 mm.

As shown in FIG. 5, the planar light emitting element 91g is mounted on the element mounting substrate 92g, and the element mounting substrate 92g is mounted on the printed circuit board 93g. The printed circuit board 93 g is mounted on the metal plate 94 g. As shown in FIG. 7, the bulk type lens 1g according to the third embodiment has a first fixing scaffold 95g protruding to the left side and integrated with an optical transmission unit 39g of the bulk type lens 1g, and protruding to the right side and bulk. It has 96 g of a second fixing scaffold integrated with 39 g of an optical transmission unit of 1 g of a type lens. A first through hole 97 g is opened in the first fixing scaffold 95 g, and a second through hole 98 g is opened in the second fixing scaffold 96 g. By passing the fixture through the first through hole 97 g and the first through hole 97 g, the bulk lens 1 g is fixed to the metal plate 94 g via the printed circuit board 93 g.

When irradiating the rectangular shape with the light from the bulk lens 1g according to the third embodiment, a uniform illuminance distribution is often required for the rectangular shape. For example, assuming that the length on the optical axis is 15 mm, the diameter of the ceiling portion 42 g is 6 mm, and the height of the side wall 43 g is 3 mm, the irradiation angle θ _{illum of} the light emitted from the central emission point in the X-axis direction is ± 8. It can be designed so that the irradiation angle of the light emitted from the central emission point in the Y-axis direction is θ _{illum = 0 degrees.} In the case of 91 g of a circular (disk-shaped) planar light emitting element having a light emitting surface of 1.8 mm in diameter, according to the bulk type lens 1 g according to the third embodiment, the irradiation light spread width in the X direction = 22 degrees, in the Y direction. Irradiation light spread width = 7 degrees. The shape of the light emitting surface does not have to be limited to a circular shape. However, from the Pythagorean theorem, in the case of a rectangle, the diagonal length corresponds to the diameter of the circle. Therefore, 91 g of a rectangular planar light emitting element having a side of 1.8 / 1.4 = 1.3 mm is housed in the circular recesses (42 g, 43 g) having a diameter of 1.8 mm. In the case of a rectangular planar light emitting element of 1.3 mm × 1.3 mm, the volumetric efficiency of the recesses (42 g, 43 g) is poor, and the uniformity of optical characteristics is also disadvantageous. In the intermediate direction between the X-axis and the Y-axis on the XY plane, the irradiation angle θ _{illum in the} Y-direction increases as the X-axis approaches. Therefore, in order to realize a uniform illuminance distribution in a rectangular shape, it is necessary to correct so that the curvature of the exit surface 36g in the Y direction becomes smaller as it approaches the X axis.

In the conventional bulk type lens as illustrated in FIGS. 11 and 12, the light having a small emission angle from the planar LED 91d is incident from the ceiling portion 42d and emitted from the first emission surface 33, and the emission angle is emitted. The large light is incident from the ceiling portion 42g, reflected by the rear outer wall surface 44d, and then emitted from the second exit surface 34. With such a conventional bulk lens, it is difficult to design the irradiation angle and the intensity distribution of the irradiation light. On the other hand, in the bulk type lens 1g according to the third embodiment, with respect to the light emitted from the light emitting center point of the planar light emitting element 91g, the light is passed through the central incident point of the ceiling portion 42g and the center of the emitting surface 36g. an irradiation angle theta _illum of the light emitted from the first emitting point area, the difference in illumination angle theta _illum of the light emitted from the second emitting point of the central region through the incident point of the ceiling portion 42g closer to the side wall 43 g 10 The angle of the tangent plane with respect to the curved surface at the first and second exit points is set so as to be within the first irradiation angle range within degrees.

Further, in the bulk type lens 1g according to the third embodiment, the light emitted from the emission center point is incident from the incident point on the uppermost side of the side wall 43g, reflected by the rear outer wall surface 44g, and the emission surface 36g. _{The irradiation angle θ illum of the} light emitted from the third exit point of the peripheral region and the light incident from the incident point at a position away from the ceiling portion 42 g of the side wall 43 g are reflected by the rear outer wall surface 44 g and the fourth emission of the peripheral region. The angle of the tangent plane with respect to the curved surface at the third and fourth exit points and the first and second reflection points so that the difference between the _{irradiation angles θ illum} emitted from the points is within the second irradiation angle range of 10 degrees or less. The angle of the tangent plane of the rear outer wall surface 44 g is set.

The first irradiation angle range and the second irradiation angle range are the same. That is, in the bulk type lens 1g according to the third embodiment, the ceiling portion 42g of the recess (42g, 43g) is made flat, and the side wall 43g is made into a quadric surface composed of a linear bus perpendicular to the ceiling portion 42g. It is designed so that the _{irradiation angle θ illum} is substantially the same when the light incident from the portion 42 g and the light incident from the side wall 43 g of the bulk lens 1 g are emitted. Therefore, according to the bulk type lens 1g according to the third embodiment, it is easy to design the light intensity including the light emitted from the end emission point deviated by the distance d, and the illuminance uniformity of the illumination range is high. can. In the description of the bulk type lens 1g according to the third embodiment, a case where the rear outer wall surface 44g can be designed under the total reflection condition will be described for convenience, but the present invention is not limited to the total reflection condition. If the total reflection conditions are not met due to conditions such as the light emission characteristics of the light emitting surface of the planar light emitting element 91 g and the outer shape of the optical transmission unit 39 g, mirror reflection treatment such as a metal film having high reflectance is performed on the rear outer wall surface 44 g. The structure may be used.

The bulk lens according to the third embodiment can be designed by the same procedure as the flowchart shown in FIG. 1E. According to the method for designing the bulk lens, the light emitter, and the bulk lens according to the third embodiment, it is possible to efficiently use the size of the light emitting surface of the planar light emitting element having a large light emitting surface area, and it is compact. Light intensity distribution with excellent uniformity over a wide irradiation area, reducing the influence of light emitted from positions such as the end light emitting point away from the central light emitting point, and increasing the light collection efficiency at a narrow irradiation angle. Can be illuminated efficiently.

(Fourth Embodiment)
In the bulk type lens 1h according to the fourth embodiment of the present invention, a lens suitable for illuminating a road from a road shoulder will be described. As shown in FIGS. 8 and 9, the bulk lens 1h according to the fourth embodiment is a bulk lens 1h that houses a main light emitting portion of a planar light emitting element 91h such as an LFD. Similar to the bulk lens 1f according to the first and second embodiments, the bulk lens 1h according to the fourth embodiment has an exit surface 36h formed of a curved surface whose curvature continuously changes and the exit surface 36h. An asymmetric bulk optical transmission unit 39h made of contacting optical media, a rear outer wall surface 44h in contact with the optical transmission unit 39h, a ceiling portion 42h provided inside the optical transmission unit 39h, and a side wall connected to the ceiling portion 42h. It is composed of 43h and includes recesses (42h, 43h) for accommodating the main light emitting portion. As the optical medium of the bulk lens 1h according to the fourth embodiment, various transparent materials as described in the bulk lens 1e according to the first embodiment can be used.

In the bulk type lens 1g according to the fourth embodiment, the light emitted from the light emitting center point of the planar light emitting element 91h passes through the central incident point of the ceiling portion 42h and is the first in the central region of the exit surface 36h. an irradiation angle theta _illum of the light emitted from the emitting point, the differences in illumination angle theta _illum of the light emitted through the incident point of the ceiling portion 42h close to the side wall 43h of the second emitting point of the central region within 10 degrees The angle of the tangent plane with respect to the curved surface at the first and second exit points is set so as to be within one irradiation angle range. Further, with respect to the light emitted from the light emitting center point of the planar light emitting element 91h, the light is incident from the incident point on the uppermost side of the side wall 43h and reflected by the rear outer wall surface 44h to be reflected by the third exit point in the peripheral region of the light emitting surface 36h. The irradiation angle θ _{illum of the} light emitted from the side wall 43h and the irradiation angle θ illum emitted from the fourth emission point of the peripheral region are reflected by the rear outer wall surface 44h and the light incident from the incident point at a position away from the ceiling portion 42h of the side wall 43h. The angle of the tangent plane with respect to the curved surface at the third and fourth exit points and the tangent plane of the rear outer wall surface 44h at the first and second reflection points so that the difference in _{illum is within the second irradiation angle range of 10 degrees or less.} The angle of is set. The first irradiation angle range and the second irradiation angle range are the same.

As shown in FIG. 8, the planar light emitting element 91h is mounted on the element mounting substrate 92h, and the element mounting substrate 92h is mounted on the printed circuit board 93h. The printed circuit board 93h is mounted on the metal plate 94h. As shown in FIG. 10, the bulk type lens 1h according to the fourth embodiment projects to the left side and is integrated with the optical transmission unit 39h of the bulk type lens 1h as shown in FIG. 10 for the first fixing scaffold 95h. It has a second fixing scaffold 96h that protrudes to the right and is integrated with the optical transmission unit 39h of the bulk lens 1h. A first through hole 97h is opened in the first fixing scaffold 95h, and a second through hole 98h is opened in the second fixing scaffold 96h. By passing the fixture through the first through hole 97h and the first through hole 97h, the bulk lens 1h is fixed to the metal plate 94h via the printed circuit board 93h.

As described below, in order to make the best use of the characteristics of the bulk lens 1h according to the fourth embodiment, it is necessary to accurately install the position of the optical transmission unit 39h with respect to the planar light emitting element 91h. Since it is difficult to fix the shape of the optical transmission portion 39h of the bulk type lens 1h according to the fourth embodiment, the first through hole 97h for screwing and the first through hole 97h for screwing between the rear outer wall surface 44d (reflection surface) and the exit surface 36h. The structure is such that a pair of the first fixing scaffold 95h and the second fixing scaffold 96h having the second through hole 98h are connected to the optical transmission unit 39h.

The road surface illuminance is inversely proportional to the square of the distance from the luminaire, and is proportional to the sinusoidal function of the angle between the illuminating light and the road surface. For example, consider a road having a median strip (the central part of the road) between the oncoming outbound route and the inbound route. Assuming that there is a roadway (outward route) 1.5 m away from the shoulder of this road and there is a roadway (return route) on the opposite side via the median strip or the center line of the road, that roadway (outward route) Width = 3.5m. In this case, 1.5 + 3.5 = 5 m from the shoulder to the median strip or the center line of the road. A case where a lighting fixture having a height of 1.1 m is installed on the shoulder of the road and the lighting fixture on the shoulder of the road is used to illuminate the road surface of the roadway (outward route) to the median strip or the center line of the road will be described.

It is assumed that the irradiation light spread width in the road width direction of the luminaire is about 24 degrees, and the center (optical axis) of the luminaire illuminates toward the median strip or the road center line. _{Under this condition, the irradiation angle θ illum} with respect to the direction toward the positions of 1.5 m, 2 m, 2.5 m, 3 m, 3.5 m, 4 m, 4.5 m, and 5 m from the road shoulder and their relative light intensities are shown in Table 1. Since the relationship is as shown, it _{is difficult to design the irradiation angle θ illum} and the intensity distribution of the irradiation light.

In Table 1, the "relative light intensity" is the light intensity in the direction toward the position of the median strip or the road center line located 5 m from the shoulder of the road, and is a ratio based on this 1. Relative light intensity.

Similar to the bulk lens 1g according to the third embodiment, the "optical axis" of the bulk lens 1h according to the fourth embodiment emits light from the planar light emitting element 91h housed inside the recesses (42h, 43h). It is defined as the center line of the optical transmission unit 39h that passes through the center of the surface and is in the normal direction of the light emitting surface. Then, the optical structure of the bulk lens 1h according to the fourth embodiment will be described in the XYZ coordinate system including the X-axis and the Y-axis orthogonal to the Z-axis with this optical axis as the Z-axis. That is, the locus of the optical path in the cross section of the bulk lens 1h in the X-axis direction of Y = 0 is shown in FIG. 8, and the locus of the optical path in the cross section of the bulk lens 1h in the Y-axis direction of X = 0 is shown in FIG. Assuming that the bulk lens 1h according to the fourth embodiment has a length of 15 mm on the optical axis, the following dimensions can be exemplified. However, the ceiling portion 42h is a flat surface, and in the cross-sectional views of FIGS. 8 and 9, the side wall having the direction of the linear generatrix orthogonal to the ceiling portion 42h is a cylindrical surface. Under such an assumption, the bulk type lens 1h can be designed with the ceiling portion 42h having a diameter of 6 mm and the side wall 43h having a height of 3 mm or the like.

First, the irradiation light spread width in the X-axis direction of the light emitted from the central light emitting point of the planar light emitting element 91h located on the optical axis is designed to be ± 20 degrees. Then, in the Y-axis direction, the irradiation angle θ _{illum in the} + Y direction is 0 degrees, and the design irradiation angle in the −Y direction is θ _illum = 0 to -20 degrees so that the light intensity distribution is as shown in Table 1. _Suppose you design an angle θ illum. + At exit surface 36h can be designed to irradiation angle theta _illum = 0 ° in the Y direction, the irradiation angle theta _illum enough Y-axis direction closer to the X-axis direction on the X-Y plane spread. Therefore, in the bulk type lens 1h according to the fourth embodiment, the shape is corrected to be asymmetric so that the curvature of the exit surface 36h in the Y-axis direction becomes small.

When the light emitting surface is a circular (disk-shaped) planar light emitting element 91h having a diameter of 1.8 mm, the spread width of the irradiation light in the X-axis direction is affected by the light emitted from the end light emitting point deviated by a distance d. Including is = about 45 degrees. The irradiation light spread width in the Y-axis direction is the irradiation near the optical axis caused by the light emitted from the end emission point whose light emitting surface is a circular planar light emitting element 91h having a diameter of 1.8 mm and deviated by a distance d. In addition to the existence of a high-luminance region with a light spread width of about ± 3.5 degrees, the light intensity distribution has a light intensity gradual decrease region in which the light intensity gradually decreases to -22.5 degrees in the Y-axis direction. The shape of the light emitting surface of the planar light emitting element 91h does not have to be limited to a circular shape. However, in the case of a rectangular planar light emitting element 91h, for example, according to the Pythagorean theorem, gaps are generated in the recesses (42h, 43h), resulting in poor volumetric efficiency and disadvantage in terms of uniformity of optical characteristics. become.

According to the bulk type lens 1h according to the fourth embodiment, the bulk type lens 1h is arranged at a position at a height of 1.1 m on the road shoulder, and the high-luminance region irradiated with the irradiation angle spread width = 7 degrees is 3. A fairly uniform road surface illuminance distribution can be realized by aligning the optical axes so that they are generated on the median strip or the road center line side, which is far from the 5 m lane. Further, in order to make the road surface illuminance distribution uniform, the height of the bulk type lens 1h may be increased, and a bulk type lens 1h having a larger diameter may be used. _{By using the bulk type lens 1h having a large diameter, the irradiation angle θ illum} due to the light emitted from the end light emitting point deviated by the distance d on the light emitting surface of the planar light emitting element 91h is reduced, and the peak light intensity is further increased. The design should be high.

When adjusting the road surface illuminance distribution to a specified value, designing is facilitated by making the ceiling portion 42h flat and the side wall 43h a quadric surface in which linear bus lines are parallel. _{Then, if the irradiation angle θ illum of the} light incident from the ceiling portion 42h and the light incident from the side wall 43h is designed to be substantially the same, the light emitted from the end emission point deviated by the distance d is included. Light intensity design becomes easy. In the description of the bulk type lens 1h according to the fourth peripheral embodiment, the case where the rear outer wall surface 44h can be designed under the total reflection condition has been described for convenience, but the case is not limited to the total reflection condition. If the total reflection conditions are not met due to conditions such as the light emission characteristics of the light emitting surface of the planar light emitting element 91h and the outer shape of the optical transmission unit 39h, a specular reflection treatment such as a metal film having high reflectance is performed on the rear outer wall surface 44h. The structure may be used.

The bulk lens according to the fourth embodiment can be designed by the same procedure as the flowchart shown in FIG. 1E. According to the method for designing the bulk type lens, the light emitting body, and the bulk type lens according to the fourth embodiment, it is possible to efficiently use the size of the light emitting surface of the planar light emitting element having a large area of the light emitting surface, and it is compact. The structure reduces the influence of light emitted from positions such as the edge emission point away from the central emission point, increases the light collection efficiency at a narrow irradiation angle, and has excellent uniformity over a wide irradiation area such as road lighting. Efficient lighting is possible with the light intensity distribution.

(Other embodiments)
As mentioned above, the present invention has been described by the first to fourth embodiments, but the statements and drawings that form part of this disclosure should not be understood as limiting the invention. Various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art from this disclosure. As described above, it goes without saying that the present invention includes various embodiments not described here. Therefore, the technical scope of the present invention is defined only by the matters specifying the invention according to the reasonable claims from the above description.

The present invention can be used in industrial fields that require particularly large area lighting such as outdoor sports stadiums, indoor lighting including dome-shaped stadiums, and street / road lighting.

1e to 1h ... Bulk type lens, 36c, 36f to 36h ... Exit surface, 36C _c ... Central area, 36C _{o ...} Peripheral area, 42e to 42h ... Ceiling, 43e to 43h ... Side wall, 44e to 44h ... Rear outer wall surface, 95e-95h ... 1st fixing scaffold, 96e-96h ... 2nd fixing scaffold, 97e-97h ... 1st through hole, 98e-98h ... 2nd through hole

Claims

A bulk type lens that houses the main light emitting part of the planar light emitting element, and the bulk type lens is
An exit surface consisting of a curved surface whose curvature changes continuously,
An optical transmission unit made of an optical medium in contact with the exit surface,
The rear outer wall surface in contact with the optical transmission unit and
A recess provided inside the optical transmission unit and a side wall connected to the ceiling, and a recess for accommodating the main light emitting unit.
When the normal direction of the light emitting surface passing through the center of the light emitting surface of the planar light emitting element is defined as the optical axis and the inclination angle from the optical axis is defined as the irradiation angle, the planar light emitting element For the light emitted from the center of the light emitting surface
The irradiation angle of light emitted from the first exit point in the central region of the exit surface through the center of the ceiling portion and the light emitted from the second exit point in the central region through the ceiling portion near the side wall. The angle of the tangent plane with respect to the curved surface at the first and second exit points is set so that the difference between the irradiation angles is within the first irradiation angle range of 10 degrees or less.
The irradiation angle of light incident from the uppermost portion of the side wall, reflected by the first reflection point on the rear outer wall surface, and emitted from the third emission point in the peripheral region of the exit surface, and away from the ceiling portion of the side wall. The light incident from the position is reflected by the second reflection point on the rear outer wall surface, and the difference in the irradiation angles emitted from the fourth emission point in the peripheral region is within the second irradiation angle range of 10 degrees or less. The angle of the tangent plane with respect to the curved surface at the third and fourth exit points and the angle of the tangent plane of the rear outer wall surface at the first and second reflection points are set.
A bulk type lens characterized in that the first irradiation angle range and the second irradiation angle range are the same.
The bulk type lens according to claim 1, wherein all the irradiation angles of the light emitted from the light emitting point located at the center of the light emitting surface of the planar light emitting element are 0 degrees.
In a coordinate system consisting of an X-axis and a Y-axis orthogonal to each other with the Z-axis as the direction of the optical axis, different irradiation angles are set in the X-axis direction and the Y-axis direction, and illumination is performed with a rectangular illuminance distribution. The bulk type lens according to claim 1 or 2, characterized in that it is designed in.
In a coordinate system consisting of an X-axis and a Y-axis orthogonal to each other with the direction of the optical axis as the Z-axis, light emitted from a light emitting point located at the center of the light-emitting surface is
Design all irradiation angles in the + or-direction of the Y axis to 0 degrees,
The bulk type lens according to claim 1 or 2, wherein the intensity of the irradiation light in the-or + direction of the Y-axis is designed to be gradually reduced.
The bulk type lens according to any one of claims 1 to 4, wherein the ceiling portion is a flat surface and the side wall portion is a quadric curved surface having a generatrix as a straight line.
The bulk type lens according to any one of claims 1 to 5, wherein the first and second fixing scaffolds are connected in pairs on both sides of the optical transmission unit.
The bulk type lens according to claim 6, wherein the first fixing scaffold is provided with a first through hole, and the second fixing scaffold is provided with a second through hole.
An exit surface consisting of a curved surface whose curvature changes continuously,
An optical transmission unit made of an optical medium in contact with the exit surface,
The rear outer wall surface in contact with the optical transmission unit and
A recess provided inside the optical transmission unit and a side wall connected to the ceiling, and a recess for accommodating the main light emitting unit.
A planar light emitting element fixed in a predetermined positional relationship is provided so as to be housed in the recess, and the optical axis is the normal direction of the light emitting surface passing through the center of the light emitting surface of the planar light emitting element. When the angle of inclination from the optical axis is defined as the irradiation angle, with respect to the light emitted from the center of the light emitting surface of the planar light emitting element.
The irradiation angle of light emitted from the first exit point in the central region of the exit surface through the center of the ceiling portion and the light emitted from the second exit point in the central region through the ceiling portion near the side wall. The angle of the tangent plane with respect to the curved surface at the first and second exit points is set so that the difference between the irradiation angles is within the first irradiation angle range of 10 degrees or less.
The irradiation angle of light incident from the uppermost portion of the side wall, reflected by the first reflection point on the rear outer wall surface, and emitted from the third emission point in the peripheral region of the exit surface, and away from the ceiling portion of the side wall. The light incident from the position is reflected by the second reflection point on the rear outer wall surface, and the difference in the irradiation angles emitted from the fourth emission point in the peripheral region is within the second irradiation angle range of 10 degrees or less. The angle of the tangent plane with respect to the curved surface at the third and fourth exit points and the angle of the tangent plane of the rear outer wall surface at the first and second reflection points are set.
A light emitting body characterized in that the first irradiation angle range and the second irradiation angle range are the same.
An exit surface made of a curved surface whose curvature continuously changes, an optical transmission unit made of an optical medium in contact with the emission surface, a rear outer wall surface in contact with the optical transmission unit, a ceiling portion provided inside the optical transmission unit, and a ceiling portion provided inside the optical transmission unit. A step of drawing an initial design outline, which is composed of a side wall connected to the ceiling portion and has a recess for accommodating the main light emitting portion.
A step of determining the relative position of the planar light emitting element housed in the recess,
The first reflection point where the light incident from the uppermost portion of the side wall reaches the rear outer wall surface and the second reflection point where the light incident from a position away from the ceiling portion of the side wall reaches the rear outer wall surface. Steps to decide and
A step of setting the angle of the tangent plane of the rear outer wall surface at the first and second reflection points so that the light reflected at the first and second reflection points reaches the peripheral region of the emission surface.
The irradiation angle of light emitted from the first exit point in the central region of the exit surface through the center of the ceiling portion and the light emitted from the second exit point in the central region through the ceiling portion near the side wall. The step of setting the angle of the tangent plane with respect to the curved surface at the first and second exit points so that the difference between the irradiation angles is within the first irradiation angle range of 10 degrees or less.
The irradiation angle of the light reflected at the first reflection point and emitted from the third emission point in the peripheral region of the emission surface, and the irradiation reflected by the second reflection point and emitted from the fourth emission point in the peripheral region. The angle of the tangent plane with respect to the curved surface at the third and fourth exit points and the rear outer wall surface at the first and second reflection points so that the angle difference is within the second irradiation angle range of 10 degrees or less. Steps to set the angle of the tangent plane of
A method of designing a bulk lens, which comprises.