JP2014229540A - Light projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light projection device which can turn a light distribution pattern into the light distribution pattern having a high evenness and a constant (or substantially constant) strength distribution.SOLUTION: A light projection device includes a laser beam source 12 and a reflection surface 14 which is arranged in such a state as to be inclined for an optical axis of the laser beam source and reflects a laser beam from the laser beam source. Therein, a reflection region r(therein, nx1 is an integer which is changed to x1 in the order of 0, 1, ....) is configured so as to reflect laser beam in a design interval xand irradiate a region a, and a reflection region -r(therein, nx2 is an integer which is changed to x2 in the order of 0, 1, ....) is configured so as to reflect laser beam in a design interval -xand irradiate a region -a.

Description

  The present invention relates to a light projecting device.

  Conventionally, a base surface having a paraboloidal shape is divided into a plurality of vertical lines and a plurality of substantially horizontal lines when viewed from the front to form a large number of small reflection areas. There is known a lamp configured to realize a target light distribution by controlling light (see, for example, Patent Document 1).

Japanese Patent No. 2796920

  However, since the lamp is a lamp premised on using a bulb-type light source such as a halogen bulb that diffuses relatively isotropically as a light source, in the lamp, a bulb-type bulb such as a halogen bulb is used as the light source. When a light source such as a semiconductor laser light source having narrower directivity than that of the light source is used, there is a problem that light distribution with a high degree of uniformity and a constant intensity distribution cannot be realized.

  The present invention has been made in view of such circumstances, and includes a laser light source and a reflection surface that reflects the laser light from the laser light source, and the laser light from the laser light source that is reflected by the reflection surface. In the light projecting device for forming a light distribution pattern having a predetermined shape by the light projecting device, the light distribution pattern can be a light distribution pattern having a high degree of uniformity and a constant (or substantially constant) intensity distribution. The purpose is to provide.

In order to achieve the above object, the invention described in claim 1 includes a laser light source and a reflecting surface that is arranged in an inclined state with respect to the optical axis of the laser light source and reflects the laser light from the laser light source. In the light projecting device for forming a light distribution pattern having a predetermined shape by the laser light from the laser light source reflected by the reflection surface, the light distribution pattern is horizontally aligned on one side with respect to the vertical line. Area a ₀ to area a _x1 arranged adjacent to each other (where x1 is an integer equal to or greater than 1. The area located closest to the vertical line is the area a ₀ and the area located farthest from the vertical line is the area. a _x1, and the area between the area a ₀ and the area a _x1 is defined as the area a ₁ , the area a ₂ ... in this order from the area a ₀ side, and the other with respect to the vertical line. of In the regions disposed adjacent horizontally -a 0 _~ region -a x2 _(where, x2 is a region located an integer of 1 or more. Most said vertical line near the area -a _0, most the vertical line A region located far from the region is referred to as a region -a _x2, and regions between the region -a ₀ and the region -a _x2 are sequentially arranged from the region -a ₀ side, region -a ₁ , region -a _2. The reflection surface is formed of a light distribution pattern including the laser light source incident on the reflection surface in a horizontal section on one side with respect to the optical axis of the laser light source. Design interval x ₀ to design interval x _x1 determined so that the energy is equal (provided that the design interval closest to the optical axis of the laser light source is the design interval x ₀ and is farthest from the optical axis of the laser light source) Located in A design section to be performed is a design section x _x1, and a design section between the design section x ₀ and the design section x _{x1 in} order from the design section x ₀ side is a design section x ₁ , a design section x _2. Reflection region r ₀ to reflection region r _x1 (however, the reflection region located closest to the optical axis of the laser light source is the reflection region r _0, and is located farthest from the optical axis of the laser light source). The reflection region is a reflection region r _x1, and the reflection region between the reflection region r ₀ and the reflection region r _x1 is a reflection region r ₁ , a reflection region r ₂ ... In order from the reflection region r ₀ side. ) And the design section −x ₀ to the design section determined so that the energy of the laser light from the laser light source incident on the reflecting surface becomes equal in the horizontal section on the other side with respect to the optical axis of the laser light source. -X _{x1 (However,} most the design section located close to the optical axis of the laser light source and design section -x _0, and most said laser light source design section -x _x1 the design section located farther from the optical axis, the design section Design intervals between −x ₀ and the design interval −x _x1 are designated as design interval −x ₁ , design interval −x ₂ ... In order from the design interval −x ₀ side. ) Corresponding to the reflection region −r ₀ to reflection region −r _x2 (where the reflection region closest to the optical axis of the laser light source is the reflection region −r ₀ and is positioned farthest from the optical axis of the laser light source). The reflective area to be reflected is the reflective area −r _x1, and the reflective area between the reflective area −r ₀ and the reflective area −r _x1 is the reflective area −r ₁ and the reflective area − in order from the reflective area −r ₀ side. r ₂ ...), and the reflection region r _nx1 (where nx 1 is an integer that changes to 0 in the order of 0, 1,...), The laser beam in the design section x _nx1 is reflected to irradiate the region a _nx1 , and the reflection region -r _nx2 (where nx2 is 0, 1,... In order of x2). Is an integer that varies up to The laser beam in _nx2 is reflected to irradiate the region- _anx2 .

  According to the first aspect of the present invention, the following advantages are obtained.

First, a light distribution pattern having a predetermined shape is formed by laser light from the laser light source reflected by the reflection surface, the laser light source and a reflection surface that reflects the laser light from the laser light source. In the light projecting device, it is possible to provide a light projecting device in which the light distribution pattern can be a light distribution pattern having a high degree of uniformity and a constant (or substantially constant) intensity distribution. This reflecting surface, the laser light source in the horizontal cross section of one side with respect to the optical axis, design section x _{0 ~} design section of the energy of the laser light is determined to be equal from a laser light source that is incident on the reflective surface The energy of the laser beam from the laser light source incident on the reflection surface is determined to be equal in the reflection region r ₀ to the reflection region r _x1 corresponding to x _x1 and the horizontal section on the other side with respect to the optical axis of the laser light source. _Are configured as a reflection surface including the reflection region -r ₀ to the reflection region -r _x2 corresponding to the design interval -x ₀ to the design interval -x _x1 , and the reflection region r _nx1 is within the design interval x _nx1 reflects the laser beam, that is configured to illuminate the area _{a nx1,} reflection region _{-r nx2} is, a laser beam in the design section _{-x nx2} reflection Te, it is configured to illuminate the area -a _nx2, it is due.

Secondly, it is possible to provide a light projecting device in which the reflected light from each of the reflection region r ₀ to the reflection region r _x1 and the reflection region −r ₀ to the reflection region −r _x2 is not collected (as a result, safety is high). It becomes possible. This reflection region _{r nx1,} reflects the laser beam in the design section _{x nx1,} be configured to illuminate an area _{a nx1,} reflection region _{-r nx2} is, in the design section _{-x nx2} It is because it is comprised so that a laser beam may be reflected and area _| region- _anx2 may be irradiated.

According to a second aspect of the present invention, in the first aspect of the present invention, the reflective surface has, in a horizontal cross section, the reflective region r ₀ to the reflective region r _x1 and the reflective region −r ₀ to the reflective region −r _x2. It is characterized by being configured as a continuous surface that is smoothly continuous without steps.

  According to the second aspect of the present invention, since each region is configured as a continuous surface that is smoothly continuous without a step, a light projecting device with less light loss compared to the case where there is a step between the regions. It becomes possible to provide.

According to the invention described in claim 3, the design section x ₁ to the design section x _x1 and the design section −x ₁ to the design section −x _x2 can be determined based on, for example, the following expression: it can.

In the invention according to claim 4, the light distribution pattern is a region b ₀ to a region b _y1 (where y1 is an integer equal to or greater than 1) arranged adjacently in the vertical direction on one side with respect to the horizontal line. A region located closer to the horizontal line is defined as a region b ₀ , a region farthest from the horizontal line is defined as a region b _y1, and a region between the region b ₀ and the region b _y1 is sequentially arranged from the region b ₀ side. Region b ₁ , region b ₂ ..., And on the other side with respect to the horizontal line, the region −b ₀ to region −b _y2 (where y2 is 1) An integer greater than or equal to the region located closest to the horizontal line as region -b ₀ , the region farthest from the horizontal line as region -b _y2, and between the region -b ₀ and the region -b _y2 the region from the region -b ₀ side , The region -b _1, the region -b ₂ ···.) Is configured as a light distribution pattern including the reflecting surface, in vertical cross-section of one side with respect to the optical axis of the laser light source, wherein Design interval y ₀ to design interval y _y1 determined so that the energy of the laser light from the laser light source incident on the reflecting surface is equal (provided that the design interval closest to the optical axis of the laser light source is the design interval) and y _0, and most said laser light source design section y _y1 the design section located farther from the optical axis, from the design section y ₀ side design section between the design section y _y1 and the design section y ₀ turn design section y _1, the design section y ₂ ···.) corresponding to the reflective region R _{0 ~} reflective region R _{y1 (provided} that reflects the reflected region located close to the optical axis of most the laser source region _0, and the most the laser light source reflected by the reflection region located away from the optical axis region R _y1, a reflection region between the reflective region R _y1 and the reflective region R ₀ in this order from the reflective region R ₀ side , the reflective region R _1, and.) to the reflective area R ₂ · · ·, in vertical cross-section on the other side with respect to the optical axis of the laser light source, the laser light energy from said laser light source incident on the reflecting surface Design interval −y ₀ to design interval −y _y2 determined so as to be equal (provided that the design interval closest to the optical axis of the laser light source is the design interval −y ₀ , and is the most from the optical axis of the laser light source) the design section located far as design section _{-y y2,} in order to design section from the design section -y ₀ side between the design section _{-y y1} and the design section -y _0, design section _-y 1, Setting And section _-y 2 ···. ) Corresponding to the reflection region −R ₀ to reflection region −R _y2 (where the reflection region closest to the optical axis of the laser light source is the reflection region −R ₀ and is positioned farthest from the optical axis of the laser light source). The reflection area to be reflected is -R _y2, and the reflection area between the reflection area -R ₀ and the reflection area -R _y2 is the reflection area -R ₁ , reflection area-in order from the reflection area -R ₀ side. R ₂ ..., And the reflection region R _ny1 (where ny1 is an integer that changes to 0 in the order of 0, 1,...), The laser beam in the design section y _ny1 is reflected to irradiate the region b _ny1 , and the reflection region -R _ny2 (where ny2 is in the order of 0, 1,... Y2 Is an integer that varies up to The laser beam in _ny2 is reflected to irradiate the region -b _ny2 .

  According to the fourth aspect of the present invention, the following advantages are obtained.

First, a light distribution pattern having a predetermined shape is formed by laser light from the laser light source reflected by the reflection surface, the laser light source and a reflection surface that reflects the laser light from the laser light source. In the light projecting device, it is possible to provide a light projecting device in which the light distribution pattern can be a light distribution pattern having a high degree of uniformity and a constant (or substantially constant) intensity distribution. This reflecting surface, the laser light source in the vertical cross section of one side with respect to the optical axis, design section y _{0 ~} design section of the energy of the laser light is determined to be equal from a laser light source that is incident on the reflective surface The energy of the laser light from the laser light source incident on the reflection surface is determined to be equal in the reflection region R ₀ to the reflection region R _y1 corresponding to y _y1 and the vertical cross section on the other side with respect to the optical axis of the laser light source. and a reflection region -R ₀ ~ reflection area _{-R x2} corresponding to the design section -y ₀ ~ design section _{-y x1,} be configured as a reflective surface comprising a reflective region _{R ny1} is, the design section _{y ny1} reflects the laser beam, that is configured to illuminate the region _{b ny1,} reflection area _{-R ny2} is, the laser light within design section _{-y ny2} reflection Te, it is configured to illuminate the area -b _ny2, it is due.

Secondly, it is possible to provide a light projecting device in which the reflected light from each of the reflection region R ₀ to the reflection region R _y1 and the reflection region −R ₀ to the reflection region −R _y2 does not collect (as a result, the safety is high). It becomes possible. This is because the reflection region R _ny1 is configured to reflect the laser light in the design interval y _ny1 and irradiate the region b _ny1 , and the reflection region −R _ny2 is in the design interval −y _ny2 . This is because the laser beam is reflected and the region -b _ny2 is irradiated.

The invention of claim 5 is the invention according to claim 4, wherein the reflective surface is in a vertical cross section, the reflection region _{R 0} ~ reflective region _{R y1,} reflective regions -R ₀ ~ reflective region _{-R y2} is It is characterized by being configured as a continuous surface that is smoothly continuous without steps.

  According to the fifth aspect of the present invention, since each region is configured as a continuous surface that is smoothly continuous without a step, a light projecting device with less light loss compared to the case where there is a step between the regions. It becomes possible to provide.

According to the invention of claim 6, the design interval y ₁ to the design interval y _y1 and the design interval −y ₁ to the design interval −y _y2 can be determined based on, for example, the following expression: it can.

  According to the present invention, a light distribution pattern having a shape predetermined by the laser light from the laser light source reflected by the reflection surface, the laser light source including a laser light source and a reflection surface that reflects the laser light from the laser light source. In the light projecting device to be formed, it is possible to provide a light projecting device in which the light distribution pattern can be a light distribution pattern having a high degree of uniformity and a constant (or substantially constant) intensity distribution.

(A) It is a perspective view of the light projector 10 of this embodiment, (b) It is a bottom view. (A), (b) The light distribution pattern of the predetermined shape formed on the screen (screen orthogonal to the reference axis AX) installed in front of the light projection device 10 by the laser light from the light projection device 10 This is an example of P. (A) Example of horizontal directivity of semiconductor laser light source (laser light source 12), (b) Example of vertical directivity of semiconductor laser light source (laser light source 12). It is a figure for demonstrating the determination method of the reflective surface 14 (horizontal cross section). It is a figure for demonstrating the determination method of a design area. It is a figure for demonstrating the determination method of the reflective surface 14 (vertical cross section). (A) Example of reflective surface 14 (horizontal cross section) of Example, (b) The horizontal cross section of reflective surface 14 shown in FIG. 7 (a) is rotated to the right by θ2 °, and the vertical axis direction is enlarged. is there. It is a figure for demonstrating the Example of the reflective surface 14 (horizontal cross section). (A) Example of light distribution pattern formed by laser light from laser light source 12 reflected by reflection surface 14 of the embodiment, (b) Radiation on horizontal line H of light distribution pattern shown in FIG. An example of the intensity distribution, (c) is an example of the radiation intensity distribution on the vertical line V of the light distribution pattern shown in FIG. It is the figure which expanded the horizontal axis direction of the vertical cross section of the reflective surface 14 shown in FIG. It is the table | surface which put together each position (X, Y) on the vertical cross section shown in FIG.

  Hereinafter, a projector according to an embodiment of the present invention will be described with reference to the drawings.

  Fig.1 (a) is a perspective view of the light projector 10 of this embodiment, FIG.1 (b) is a bottom view. 2 (a) and 2 (b) are determined in advance by a laser beam from the light projecting device 10 formed on a screen (a screen orthogonal to the reference axis AX) installed in front of the light projecting device 10. It is an example of the light distribution pattern P of a shape.

As shown in FIG. 1 (a), FIG. 1 (b), the light projecting device 10 of the present embodiment is arranged in a state inclined with respect to the optical axis AX ₁₂ of the laser light source 12 and the laser light source 12, a laser light source 2 and a reflection surface 14 that reflects the laser beam Ray from the laser light ray 12, and a rectangular light distribution pattern P that is predetermined by the laser beam Ray from the laser light source 12 that is reflected by the reflection surface 14 (FIG. 2A). It is comprised as a light projector which forms FIG.2 (b). The light distribution pattern P may be a light distribution pattern other than a rectangular shape, for example, a circle, an ellipse, or any other appropriate shape. The light projecting device 10 is used, for example, as a light projector for sensors that measure the presence / absence of an object, distance, and the like.

  The laser light source 12 is a light source having a Gaussian distribution different in the vertical direction and the horizontal direction and having narrow directivity characteristics compared to a bulb-type light source such as a halogen bulb, and is, for example, a semiconductor laser light source. FIG. 3A shows an example of the horizontal directivity of the semiconductor laser light source (laser light source 12), and FIG. 3B shows an example of the vertical directivity of the semiconductor laser light source (laser light source 12).

As shown in FIG. 1B, the laser light source 12 is arranged in a state where the optical axis AX ₁₂ is inclined by a predetermined angle θ1 (60 ° in this embodiment) with respect to the reference axis AX.

As shown in FIG. 1A, the reflecting surface 14 is a reflecting surface whose basic shape is a shape corresponding to a light distribution pattern P having a predetermined shape (in this embodiment, a rectangular shape). As shown in b), they are arranged in a state inclined by a predetermined angle θ2 (30 ° in this embodiment) with respect to a plane orthogonal to the reference axis AX. The reason why the reflecting surface 14 is disposed at a predetermined angle θ2 (30 ° in the present embodiment) with respect to a plane orthogonal to the reference axis AX is that the holding member 16 (laser light source) that holds the laser light source 12 is disposed. This is to prevent the light distribution pattern P from being shaded by the laser light from the laser light source 12 being blocked by the structural member that fixes 12 (see FIG. 1B). Hereinafter, a description will be given assuming that the optical axis AX ₁₂ of the laser light source 12 and the reference axis AX is included in the same horizontal plane.

  The light distribution pattern P and the reflection surface 14 are the same as the light distribution pattern P having a predetermined shape formed by the laser light from the laser light source 12 reflected by the reflection surface 14, and the intensity distribution is constant ( In order to obtain a light distribution pattern of (or substantially constant), it is configured as follows.

As shown in FIG. 2A, the light distribution pattern P is a rectangular region a ₀ to region arranged adjacent to each other in the horizontal direction on one side with respect to the vertical line V (right side in FIG. 2A). A rectangular region -a including a _x1 (where x1 is an integer of 1 or more) and arranged adjacent to the vertical line V on the other side (left side in FIG. 2A) in the horizontal direction. It is configured as a rectangular light distribution pattern including ₀ to region-a _x2 (where x2 is an integer of 1 or more). Note that x1 and x2 may have a relationship of x1 = x2, or may have a relationship of x1 ≠ x2. As x1 and x2 are increased, the light distribution pattern P can be a light distribution pattern having a higher degree of uniformity and a more constant intensity distribution.

However, on one side relative to the vertical line V (FIGS. 2 (a) middle right), most regions located vertical line V toward the region a _0, a region located far away from the most vertical line V and regions a _x1 , in order to the region between the region _{a 0} and the region _{a x1} from the area _{a 0} side, regions _{a 1,} a region _a 2 · · ·. Further, the other side with respect to the vertical line V (FIGS. 2 (a) middle left), a region located in the most vertical line V toward the area -a _0, an area located far from the most vertical line V region -a and _x2, in order to regions from the area -a ₀ side between the region -a ₀ and the area _{-a x2,} region -a _1, a region _-a 2 · · ·.

In addition, as shown in FIG. 2B, the light distribution pattern P is a rectangular region b ₀ to b that are arranged adjacent to each other in the vertical direction on one side with respect to the horizontal line H (upper side in FIG. 2B). A rectangular region that includes a region b _y1 (where y1 is an integer equal to or greater than 1) and is adjacent to the horizontal line H on the other side (lower side in FIG. 2B) in the vertical direction − It is configured as a light distribution pattern including b ₀ to region-b _y2 (where y2 is an integer of 1 or more). Note that y1 and y2 may have a relationship of y1 = y2 or a relationship of y1 ≠ y2. As y1 and y2 are increased, the light distribution pattern P can be a light distribution pattern having a higher degree of uniformity and a more constant intensity distribution.

However, on one side with respect to the horizontal line H (upper side in FIG. 2B), the region located closest to the horizontal line H is defined as a region b ₀ , the region located farthest from the horizontal line H is defined as a region b _y1 , and the region b the region between the ₀ and the area _{b y1} in order from the area _{b 0} side, regions _{b 1,} and a region _b 2 · · ·. Further, the other side relative to the horizontal H (FIG. 2 (b) middle and lower side), a region located in the most horizontal line H toward the region -b _0, an area located far from the most horizontal line H and region -b _y2 , in order to regions from the area -b ₀ side between the region -b ₀ and area _{-b y2,} region -b _1, the region _-b 2 · · ·.

  Next, a method for determining the reflecting surface 14 (horizontal cross section and vertical cross section) will be described.

  FIG. 4 is a diagram for explaining a method of determining the reflecting surface 14 (horizontal cross section).

As shown in FIG. 4, the reflecting surface 14 has energy of laser light from the laser light source 12 incident on the reflecting surface 14 in a horizontal section on one side (right side in FIG. 4) with respect to the optical axis AX ₁₂ of the laser light source 12. Including the reflection region r ₀ to the reflection region r _x1 corresponding to the design interval x ₀ to the design interval x _x1 , and the other side of the laser light source 12 with respect to the optical axis AX ₁₂ (in FIG. 4). In the horizontal cross section on the left side), the reflection region corresponding to the design interval −x ₀ to the design interval −x _x1 determined so that the energy of the laser light from the laser light source 12 incident on the reflection surface 14 is equal to −r ₀ to It is configured as a reflective surface including the reflective region -r _x2 .

However, in horizontal cross-section on one side relative to the optical axis AX ₁₂ of the laser light source 12 (in FIG. 4 right), a design section located in the optical axis AX ₁₂ side of the most laser light source 12 and design section x _0, most laser source the design section located farther from the optical axis _{AX 12} of 12 the design section _{x x1,} in order from the design section _{x 0} side design section between the design section _{x x1} and design section _{x 0,} design section _{x 1,} designed Let it be section x ₂ . Similarly, in horizontal cross section on the other side (in FIG. 4 left) with respect to the optical axis AX ₁₂ of the laser light source 12, and a design section -x ₀ the design section located in the optical axis AX ₁₂ side of the most laser light source 12, most the design section located farther from the optical axis _{AX 12} of the laser light source 12 and design section _{-x x1,} in order from the design section -x ₀ side design section between the design section _{-x x1} and design section -x _0, Design interval -x ₁ , design interval -x ₂ .

Further, in the horizontal cross section of one side with respect to the optical axis AX ₁₂ of the laser light source 12 (in FIG. 4 right), the reflective region located to the optical axis AX ₁₂ side of the most laser light source 12 to the reflective area r _0, most laser source the reflective region located far away from the optical axis _{AX 12} of 12 and the reflection region _{r x1,} in order from the reflection region _{r 0} side reflection region between the reflection region _{r 0} and the reflection region _{r x1,} reflection region _{r 1,} reflecting Region r ₂ ... Similarly, in horizontal cross section on the other side with respect to the optical axis AX ₁₂ of the laser light source 12 (the left side in FIG. 4), the reflective region located to the optical axis AX ₁₂ side of the most laser light source 12 to the reflective area -r _0, most in order from the reflective region -r ₀ side reflective area between the reflective region located far away from the optical axis _{AX 12} of the laser light source 12 to the reflective area _{-r x1,} and the reflection area -r ₀ and the reflective region _{-r x1,} It is assumed that the reflection area-r ₁ , the reflection area-r ₂ .

First, a method for determining the design interval x ₀ to the design interval x _x1 (and the design interval −x ₀ to the design interval −x _x2 ) will be described.

  FIG. 5 is a diagram for explaining a design section determination method.

  The following processing is realized by, for example, reading predetermined software (program) into a computer and executing it.

Design interval x ₀ to design interval x _x1 (and design interval −x ₀ to design interval −x _x2 ) are set for each interval where the integral value of the normal distribution function is constant (x ₀ , x ₁ ...). The design interval is determined so that the respective areas to be equalized). The design interval x ₀ to the design interval x _x1 (and the design interval −x ₀ to the design interval −x _x2 ) can be determined using, for example, the following equation (normal distribution function).

For example, in the case of a Gaussian beam having a spread of 40 °, σ = 0.174425, and when the design section x _{0 is set} to 0 ° to 3 °, the design section x ₁ , the design section x ₂ , and the design section x ₃ are each 3 ° to 6.31 °, 6.31 ° to 10.53 °, and 10.53 ° to 19.09 °. The value of design section x ₀ is an initial value determined arbitrarily by the designer at the start design. Design section x ₁ and later, because it is calculated based on the value of the design section x _0, the division number of design cross section is determined by the value of the design section x _0. Also, if the number of divisions is large, the degree of uniformity of the formed light distribution is high, and if it is small, the generated cross-sectional line is a simple curve with a small number of control points, so it is used in the calculation process and NC machining. CAM data can be easily created. Based on these, the value of the design section x ₀ is set to an appropriate value.

Next, a method of determining the light distribution sharing range (for example, the reflection region r ₀ to the reflection region r _x1 and the reflection region −r ₀ to the reflection region −r _x2 ) for each of the determined design sections will be described.

  The following processing is realized by, for example, reading predetermined software (program) into a computer and executing it.

First, as shown in FIG. 4, a horizontal section (hereinafter simply referred to as a horizontal section) including the optical axis AX ₁₂ of the laser light source 12 is divided (divided) into the determined design sections. That is, the horizontal cross-section, the straight line L1 and ± 3 ° inclined with respect to the optical axis _{AX 12} of the laser light source 12, -L1, ± 6.31 ° inclined straight line L2, -L2, ± 10.53 ° inclined straight line L3, -L3, Comparted by straight lines L4 and -L4 inclined by ± 19.09 °.

Next, a micro-reflecting surface A that reflects the laser beam on the optical axis AX ₁₂ of the laser light source 12 in the direction of the reference axis AX and irradiates the center of the light distribution pattern P (intersection of the vertical line V and the horizontal line H). Set.

Next, a circle in contact with the minute reflecting surface A at the intersection cp ₀ of the optical axis AX ₁₂ and micro reflecting surface A of the laser light source 12 is set to a horizontal cross-section. The center of this circle is located on the opposite side of the reflecting surface 14 from the laser light source 12. Arc between the intersection cp ₁ and the intersection cp ₀ of the circle and the straight line L1 is used as the reflection region _{r 0.}

The radius of this circle is adjusted so that the laser beam in the design section x ₀ reflected by the arc (reflection area r ₀ ) between the intersection point cp ₁ and the intersection point cp ₀ irradiates the area a ₀ . . Specifically, the laser beam reflected at the intersection cp ₁ is adjusted to a size that goes to the boundary between the region a ₀ and the region a ₁ .

As described above, first, corresponding to the design section x _0, and reflects the laser beam in the design section x _0, reflecting its surface shape to illuminate the regions a ₀ is configured region r ₀ is determined.

Next, a circle tangent to the reflective region _{r 0} at the intersection cp _1, sets a horizontal cross-section. The center of this circle is located on the opposite side of the reflecting surface 14 from the laser light source 12. An arc between the intersection point cp ₂ and the intersection point cp ₁ between the circle and the straight line L ₂ is used as the reflection region r ₁ .

The radius of this circle is adjusted so that the laser beam in the design section x ₁ reflected by the arc (reflection area r ₁ ) between the intersection point cp ₂ and the intersection point cp ₁ irradiates the area a ₁ . . Specifically, the laser beam reflected at the intersection point cp ₂ is adjusted to a size towards the boundary between the region a ₁ and region a _2.

As described above, it corresponds to the design section x _1, and reflects the laser beam of the design section x _1, the reflection region r ₁ whose surface shape is configured to illuminate an area a ₁ It is determined.

Next, a circle in contact with the reflective region _{r 1} at the intersection cp _2, set the horizontal cross-section. The center of this circle is located on the opposite side of the reflecting surface 14 from the laser light source 12. Arc between the intersection cp ₃ and the intersection point cp ₂ between the circle and the straight line L3 is used as the reflection region _{r 2.}

The radius of this circle, the intersection cp ₃ and the laser light within design section x ₂ that is reflected by the arc (the reflection region r ₂₎ between the intersection cp ₂ have been adjusted so as to irradiate an area a ₂ . Specifically, the laser beam reflected at the intersection point cp ₃ is adjusted to a size towards the boundary between the region a ₂ and the region a _3.

As described above, it corresponds to the design section x _2, and reflects the laser beam of the inner design section x _2, the reflection region r ₂ in which the surface shape is configured to illuminate an area a ₂ It is determined.

Similarly, the reflection area... R _x1 and the reflection area −r ₀ to the reflection area −r _x2 are determined.

As described above, the reflective surface 14 is in horizontal cross section on one side relative to the optical axis _{AX 12} of the laser light source 12 (in FIG. 4 right), design section _{x nx1} (however, nx1 is 0, 1, ... of turn, corresponds to an integer.) varying from x1, and reflects the laser beam in the design section _{x nx1,} includes a reflection region _{r nx1} irradiating the region _{a nx1,} and the optical axis of the laser light source 12 in horizontal cross-section on the other side against the AX ₁₂ (left side in FIG. 4), design section _{-x nx2} (however, nx2 is 0, in the order of ..., integers. varying from x2) corresponding to, and, It is configured as a reflection surface including a reflection region -r _nx2 that reflects the laser light in the design section -x _nx2 and irradiates the region -a _nx2 .

  FIG. 6 is a diagram for explaining a method of determining the reflecting surface 14 (vertical cross section).

The reflecting surface 14 (a vertical cross section) also by the same method as the determination method of the reflective surface 14 (horizontal cross section), in the vertical cross section of one side with respect to the optical axis AX ₁₂ of the laser light source 12 (upper side in FIG. 6), designed _{Corresponds to the} section y _ny1 (where ny1 is an integer that changes to y1 in the order of 0, 1,...) _And reflects the laser light in the design section y _ny1 to irradiate the region b _ny1 . includes a reflective region _{R ny1} to, and in the vertical cross section on the other side with respect to the optical axis _{AX 12} of the laser light source 12 (the lower in Fig. 6 side), design section _{-y ny2} (however, ny2 is 0,1, ... _-An integer that changes to y2 in the order of), and is configured as a reflective surface including a reflective region _-Rny2 that reflects the laser light in the design section _-yny2 and irradiates the region _-bny2 Has been.

In the horizontal cross section, each arc (for example, the arc (reflection region r ₀ ) and the adjacent arc (reflection region r ₁ )) are connected in a tangential line. Therefore, the reflection surface 14 is a continuous surface in which the reflection region r ₀ to the reflection region r _x1 and the reflection region −r ₀ to the reflection region −r _x2 are smoothly continuous without any step in the horizontal cross section. In this way, in the horizontal cross section, since each reflection region is configured as a continuous surface that is smoothly continuous without a step, a light projecting device with less light loss compared to the case where a step exists between each reflection region. It becomes possible to provide.

Similarly, in the vertical cross section, each arc (for example, the arc (reflection region R ₀ ) and the adjacent arc (reflection region R ₁ )) are connected in a tangent line. Therefore, the reflection surface 14 is a continuous surface in which the reflection region R ₀ to the reflection region R _y1 and the reflection region −R ₀ to the reflection region −R _y2 are smoothly continuous without any step in the vertical cross section. In this way, in the vertical cross section, since each reflection region is configured as a continuous surface that is smoothly continuous without a step, a light projecting device with less light loss compared to the case where a step exists between each reflection region. It becomes possible to provide.

  As shown in FIG. 1B, the reflection surface 14 configured as described above is in a state inclined by a predetermined angle θ2 (30 ° in the present embodiment) with respect to a plane orthogonal to the reference axis AX.

  Next, an example performed to confirm the effect of the reflecting surface 14 will be described.

In this embodiment, as shown in FIG. 7 (a), the laser light source 12, the predetermined angle θ1 optical axis AX ₁₂ is relative to the reference axis AX are arranged in (in this example, 60 °) inclined state ing. The reflection surface 14 is a reflection surface having a rectangular shape corresponding to the light distribution pattern P having a predetermined shape as a basic shape, and as shown in FIG. 7A, the reflection surface 14 is on a plane orthogonal to the reference axis AX. Are arranged in a state inclined at a predetermined angle θ2 (30 ° in this embodiment). It is included in the same horizontal plane to the optical axis AX ₁₂ and the reference axis AX of the laser light source 12.

In the present embodiment, the light distribution pattern P is arranged on the one side (right side in FIG. 2A) with respect to the vertical line V and is adjacent to the horizontal direction in a region a ₀ to region a _x1 (where x1 = 24) and on the other side (the left side in FIG. 2A) with respect to the vertical line V, the region −a ₀ to the region −a _x2 (here, x2 = 24) arranged adjacent to each other in the horizontal direction. A light distribution pattern including Further, the light distribution pattern P includes, on one side with respect to the horizontal line H (upper side in FIG. 2B), the area b ₀ to the area by ₁ adjacent to each other in the vertical direction, and the other side with respect to the horizontal line H. the side of the (see FIG. 2 (b) middle and lower side) was constructed as a light distribution pattern including a region -b 0 _~ region -b _y2 disposed adjacent vertically.

In the present embodiment, the reflecting surface 14 includes a reflecting region r ₀ to a reflecting region r _x1 in a horizontal section on one side (right side in FIG. 4) with respect to the optical axis AX ₁₂ of the laser light source 12, and a laser. In the horizontal cross section on the other side (left side in FIG. 4) with respect to the optical axis AX ₁₂ of the light source 12, the light source 12 is configured as a reflection surface including the reflection region −r ₀ to the reflection region −r _x2 .

In FIG. 8, the range between the start angle 0 and the end angle 0.5 corresponds to the design range r _0, and the range between the start angle 0.5 and the end angle 1.001 is the design range r _1. The range between the start angle 20.21 and the end angle 29.3 corresponds to the design range r _x1 . In FIG. 8, a circle (arc) with a right radius of 74.38 corresponds to the reflection region r ₀ , a circle (arc) with a right radius of 78.45 corresponds to the reflection region r ₁ ,. A circle (arc) of 195.315 corresponds to the reflection region r _x1 . Similarly, a circle (arc) with a left radius of 73.45 corresponds to the reflection region -r ₀ , a circle (arc) with a left radius of 75.5 corresponds to the reflection region -r ₁ ,... .09 circle (arc) corresponds to the reflection region -r _x2 . In FIG. 8, the signs of the right radius and the left radius are changed to “−” in the middle (see, for example, the right radius −637.4 and the left radius −337 in FIG. 8). "Represents that the center of the circle (arc) of the right radius and the circle (arc) of the left radius is located on the laser light source 12 side with respect to the reflection surface 14.

  In the reflecting surface 14 of the present embodiment, as described above, as a result of the signs of the right radius and the left radius changing to “−” in the middle, the horizontal cross section of the reflecting surface 14 is as shown in FIG. The shape includes at least two inflection points fp1 and fp2. FIG. 7B is an enlarged view of the vertical axis direction by rotating the horizontal cross section of the reflecting surface 14 shown in FIG. 7A to the right by θ2 °. Depending on the values of x1, x2, y1, and y2, the shape does not include the inflection point.

In the present embodiment, the reflection surface 14 includes a reflection region R ₀ to a reflection region R _y1 in a vertical cross section on one side (upper side in FIG. 6) with respect to the optical axis AX ₁₂ of the laser light source 12, and laser in vertical cross section on the other side with respect to the optical axis _{AX 12} of the light source 12 (the lower in Fig. 6 side), it is configured as a reflective surface comprising a reflective region _{R 0} ~ reflective region _{-R y2.}

The vertical cross section of the reflecting surface 14 of the present embodiment has the shape shown in FIG. FIG. 10 is an enlarged view of the horizontal axis direction of the vertical section of the reflecting surface 14 shown in FIG. In FIG. 10, the vertical cross section of the reflecting surface 14 is drawn as a continuous surface in which the positions represented by Z and Y shown in FIG. 11 are connected by, for example, a spline curve. In addition, each position represented by Z and Y shown in FIG. 11 is the intersection of the above-described-..., -Cp ₄ , -cp ₃ , -cp ₂ , -cp ₁ , cp ₀ , cp ₁ , cp ₂ , cp _3. , Cp ₄ ...

  FIG. 9A shows an example of a light distribution pattern P formed by the laser light from the laser light source 12 reflected by the reflecting surface 14 of the present embodiment, and FIG. 9B shows the distribution shown in FIG. FIG. 9C shows an example of the radiant intensity distribution on the horizontal line H of the light pattern P, and FIG. 9C shows an example of the radiant intensity distribution on the vertical line V of the light distribution pattern P shown in FIG.

  Referring to FIG. 9B, the light distribution pattern P formed by the laser light from the laser light source 12 reflected by the reflecting surface 14 of this embodiment has a high degree of uniformity and a constant intensity distribution in the horizontal direction. (Or substantially constant). Referring to FIG. 9C, the light distribution pattern P formed by the laser light from the laser light source 12 reflected by the reflecting surface 14 of this embodiment has a high degree of uniformity in the vertical direction, and an intensity distribution. Is constant (or substantially constant).

  As described above, according to the light projecting device 10 of the present embodiment, the following advantages are produced.

  First, the light distribution pattern P includes a laser light source 12 and a reflection surface 14 that reflects the laser light from the laser light source 12, and has a predetermined shape by the laser light from the laser light source 12 reflected by the reflection surface 14. In the light projecting device 10 that forms the light distribution device, it is possible to provide a light projecting device in which the light distribution pattern P can be a light distribution pattern having a high degree of uniformity in the horizontal direction and a constant (or substantially constant) intensity distribution. It becomes possible.

This is a design in which the reflecting surface 14 is determined so that the energy of the laser light from the laser light source 12 incident on the reflecting surface 14 is equal in a horizontal section on one side with respect to the optical axis AX ₁₂ of the laser light source 12. The laser light source that includes the reflection area r ₀ to the reflection area r _x1 corresponding to the section x ₀ to the design section x _x1 and that is incident on the reflection surface 14 in the horizontal cross section on the other side with respect to the optical axis AX ₁₂ of the laser light source 12 12 is configured as a reflection surface including a reflection region −r ₀ to a reflection region −r _x2 corresponding to design interval −x ₀ to design interval −x _x2 determined so that the energy of the laser beam from 12 is equal. , the reflection region _{r nx1} (however, nx1 is 0, in the order of ..., integers varying from x1.) is, to reflect the laser beam in the design section _{x nx1} , It is configured to illuminate the area _{a nx1,} reflection region _{-r nx2} (however, nx2 is 0, in the order of ..., integers. Varying from x2) is, in the design section _{-x nx2} This is because the laser beam is reflected to irradiate the region _-anx2 .

  Secondly, the light distribution pattern P includes a laser light source 12 and a reflection surface 14 that reflects the laser light from the laser light source 12, and has a predetermined shape by the laser light from the laser light source 12 reflected by the reflection surface 14. It is possible to provide a light projecting device that can make the light distribution pattern P a light distribution pattern having a high degree of uniformity and a constant (or substantially constant) intensity distribution in the vertical direction. It becomes possible.

This is a design in which the reflection surface 14 is determined so that the energy of the laser light from the laser light source 12 incident on the reflection surface 14 is equal in the vertical cross section on one side with respect to the optical axis AX ₁₂ of the laser light source 12. The laser light source that includes the reflection area R ₀ to the reflection area R _y1 corresponding to the section y ₀ to the design section y _y1 and that is incident on the reflection surface 14 in the vertical cross section on the other side with respect to the optical axis AX ₁₂ of the laser light source 12 12 is configured as a reflection surface including a reflection region −R ₀ to a reflection region −R _y2 corresponding to design interval −y ₀ to design interval −y _y2 determined so that the energy of the laser beam from 12 is equal. , the reflective region _{R ny1} (where, ny1 is 0, in the order of ..., integers varying from y1.) is, to reflect the laser beam in the design section _{y ny1} , It is configured to illuminate the region _{b ny1,} reflection region _{-R ny2} (however, ny2 is 0, in the order of ..., integers. Varying from y2) is, in the design section _{-y ny2} This is because the laser beam is reflected to irradiate the region -b _ny2 .

Third, the light projecting device 10 that does not collect the reflected light from each of the reflection region r ₀ to the reflection region r _x1 and the reflection region −r ₀ to the reflection region −r _x2 (as a result, high safety) is provided. Is possible. This is because the reflection region r _nx1 (where nx1 is an integer that changes to x1 in the order of 0, 1,...) _Reflects the laser light in the design section x _nx1 and irradiates the region a _nx1 . The reflection region −r _nx2 (where nx2 is an integer that changes to x2 in the order of 0, 1,...) _Reflects the laser light in the design interval −x _nx2 . , Because it is configured to irradiate the region-a _nx2 .

_Fourthly , it is possible to provide a light projecting device in which reflected light from each of the reflection region R ₀ to the reflection region R _y1 and the reflection region −R ₀ to the reflection region −R _y2 does not collect (as a result, safety is high). It becomes possible. This is because the reflection region R _ny1 (where ny1 is an integer that changes to y1 in the order of 0, 1,...) _Reflects the laser light in the design section y _ny1 and irradiates the region b _ny1 . The reflection region −R _ny2 (where ny2 is an integer that changes to y2 in the order of 0, 1,...) _Reflects the laser light in the design interval −y _ny2 . , Region -b _ny2 is configured to be irradiated.

  Next, a modified example will be described.

In the above-described embodiment, the horizontal cross section (same for the vertical cross section) of the reflection surface 14 is connected to each arc (for example, the arc (reflection area r ₀ ) and the adjacent arc (reflection area r ₁ )) continuously. However, the present invention is not limited to this example.

For example, the horizontal cross section of the reflecting surface 14 (a vertical cross section as well), each intersection _{··· -cp 4, -cp 3, -cp} 2, -cp 1, cp 0, cp 1, cp 2, cp 3, cp ₄ ... May be configured as a continuous surface connected by a spline curve.

  Moreover, although the said embodiment demonstrated the example which comprised the reflective surface 14 as a reflective surface which makes a rectangular shape basic shape, as shown to Fig.1 (a), this invention is not limited to this.

  For example, when the light distribution pattern P is an elliptical light distribution pattern other than the rectangular shape, the reflective surface 14 may be configured as a reflective surface having an elliptical shape corresponding to the light distribution pattern P as a basic shape.

  Each of the above numerical values is an example, and appropriate numerical values can be used as θ1, θ2, numerical values in FIGS. 8 and 11, and the like.

  The above embodiment is merely an example in all respects. The present invention is not construed as being limited to these descriptions. The present invention can be implemented in various other forms without departing from the spirit or main features thereof.

10 ... light emitting device, 12 ... laser light source, 14 ... reflecting _{surface, r 0 ~r x1, -r 0} ~r x2 ... reflective _{area, R 0 ~R y1, -R 0} ~R y2 ... reflective area, _{x 0 ~x x1, -x 0 ~x} x2 ... design _{section, y 0 ~y y1, -y 0} ~y y2 ... design section

Claims (6)

A laser light source and a reflection surface that is arranged in an inclined state with respect to the optical axis of the laser light source, and reflects the laser light from the laser light source, and is reflected by the laser light from the laser light source reflected by the reflection surface In a light projecting device that forms a light distribution pattern of a predetermined shape,
The light distribution pattern is a region a ₀ to region a _x1 (where x1 is an integer equal to or greater than 0. The region located closest to the vertical line) The region a ₀ is the region farthest from the vertical line, the region a _x1, and the region between the region a ₀ and the region a _x1 is sequentially from the region a ₀ side, the region a ₁ , the region a ₂ and the region −a ₀ to region −a _x2 (where x2 is an integer greater than or equal to 0), which are arranged adjacent to each other in the horizontal direction on the other side with respect to the vertical line. The region located closer to the vertical line is defined as region -a ₀ , the region farthest from the vertical line is defined as region -a _x2, and the region between the region -a ₀ and the region -a _x2 is defined as the region -a _0. in order from the area -a ₀ side, area -a _1, area and a ₂ ···.) is configured as a light distribution pattern including,
The reflection surface has a design interval x ₀ to a design interval determined so that the energy of laser light from the laser light source incident on the reflection surface is equal in a horizontal cross section on one side with respect to the optical axis of the laser light source. x _x1 (however, the design section located closest to the optical axis of the laser light source is the design section x ₀ , the design section farthest from the optical axis of the laser light source is the design section x _{x 1} , and the design section x ₀ and a design section between the design section _{x x1} sequentially from the design section _{x 0} side, design section _{x 1,} and design section _x 2 · · ·. corresponding to) the reflective region _{r 0} ~ reflection region r _{x1 (However,} most reflective region located close to the optical axis of the laser light source and the reflective area r _0, and a reflective region located far from the optical axis of most the laser light source and the reflective region r _x1, A reflection region between the serial and the reflection region r ₀ and the reflection region r _x1 sequentially from the reflective region r ₀ side, the reflection region r _1, a reflection region r ₂ · · ·.), The light of the laser light source Design interval −x ₀ to design interval −x _x1 (provided that the laser is the most in the horizontal section on the other side with respect to the axis) determined so that the energy of the laser light from the laser light source incident on the reflecting surface becomes equal. A design section located near the optical axis of the light source is designated as a design section -x ₀ , a design section located farthest from the optical axis of the laser light source is designated as a design section -x _x1 , and the design section -x ₀ and the design section . the design section between the -x _x1 sequentially from the design section -x ₀ side, the design section -x _1, a design section _-x 2 · · ·) corresponding to the reflective region -r ₀ ~ reflective area - r _x2 (However, most The reflective region located close to the optical axis of the serial laser light source and the reflective region -r _0, and most the laser reflected by the reflection region located far away from the optical axis of the light source regions -r _x1, the said reflective region -r ₀ The reflection area between the reflection area-r _x1 and the reflection area-r _{0 is} sequentially formed from the reflection area-r ₀ side as a reflection area-r ₁ , reflection area-r ₂ . And
The reflection region r _nx1 (where nx1 is an integer that changes to x1 in the order of 0, 1,...) _Reflects the laser light in the design section x _nx1 and irradiates the region a _nx1 . Is configured as
The reflection region -r _nx2 (where nx2 is an integer that changes to x2 in the order of 0, 1,...) _Reflects the laser light in the design section -x _nx2 and the region -a _nx2 It is comprised so that it may irradiate. The reflection surface is configured as a continuous surface in which the reflection region r ₀ to the reflection region r _x1 and the reflection region −r ₀ to the reflection region −r _x2 are smoothly continuous in a horizontal section without a step. The light projecting device according to claim 1. 2. The light projecting device according to claim 1, wherein the design section x ₁ to the design section x _x1 and the design section −x ₁ to the design section −x _x2 are determined based on the following expression. .

The light distribution pattern has regions b ₀ to b _y1 (where y1 is an integer greater than or equal to 0. The region b closest to the horizontal line is the region b) arranged adjacently in the vertical direction on one side with respect to the horizontal line. _0, and a region located far away from the most the horizontal line and area _{b y1,} the region between the region _{b 0} and the area _{b y1} sequentially from the area _{b 0} side, regions _{b 1,} area _b 2 · · And -b ₀ to region-b _y2 (where y2 is an integer greater than or equal to 0. closest to the horizontal line) a region located a region -b _0, a region located far away from the most the horizontal line and area _{-b y2,} a region between said region -b ₀ region _{-b y2} from the region -b ₀ side in turn, the region -b _1, area and b ₂ · · ·.) is configured as a light distribution pattern including,
In the vertical section on one side with respect to the optical axis of the laser light source, the reflection surface is designed such that the energy of the laser light from the laser light source incident on the reflection surface is equal to the design interval y ₀ to the design interval y _y1 (however, the design section located closest to the optical axis of the laser light source is the design section y ₀ , the design section located farthest from the optical axis of the laser light source is the design section y _y1 , and the design section y the design section between ₀ and the design section _{y y1} sequentially from the design section _{y 0} side, design section _{y 1,} corresponds to.) and design section _y 2 · · · reflective region _{R 0} ~ reflective region R _{y1 (However,} most reflective region located close to the optical axis of the laser light source and the reflective area R _0, and a reflective region located far from the optical axis of most the laser light source and the reflective region R _y1, A reflection region between the serial and the reflective region R ₀ and the reflection region R _y1 sequentially from the reflective region R ₀ side includes to.) And the reflective region R _1, the reflective region R ₂ · · ·, and the laser In a vertical section on the other side of the optical axis of the light source, the design interval −y ₀ to the design interval −y _y2 (provided that the energy of the laser light from the laser light source incident on the reflection surface is equal) The design section located closest to the optical axis of the laser light source is designated as a design section -y ₀ , the design section located farthest from the optical axis of the laser light source is designated as the design section -y _y2 , and the design section -y ₀ in order to design section from the design section -y ₀ side between the design section _{-y y1,} design section -y _1, a design section _-y 2 ···.) corresponding to the reflective region _-R 0 ~ reflection area _{-R y2} ( And, most said reflective region located close to the optical axis of the laser light source and the reflective area -R _0, and most said reflecting reflective region located far away from the optical axis of the laser light source area -R _y2, the reflection region -R _The reflective area between ₀ and the reflective area −R _y2 is configured as a reflective surface including the reflective area −R ₁ , the reflective area −R ₂ ... In this order from the reflective area −R ₀ side. And
The reflection region R _ny1 (where ny1 is an integer that changes to y1 in the order of 0, 1,...) _Reflects the laser light in the design section y _ny1 and irradiates the region b _ny1 . Is configured as
The reflection region −R _ny2 (where ny2 is an integer that changes to y2 in the order of 0, 1,...) _Reflects the laser light in the design section −y _ny2 , and the region −b _ny2. The light projecting device according to claim 1, wherein the light projecting device is configured to irradiate the light. The reflection surface is configured as a continuous surface in which the reflection region R ₀ to the reflection region R _y1 and the reflection region −R ₀ to the reflection region −R _y2 are smoothly continuous in a vertical section. The light projection device according to claim 4. 6. The projection according to claim 4, wherein the design section y ₁ to the design section y _y1 and the design section −y ₁ to the design section −y _y2 are determined based on the following formula. Optical device.

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