Adapter and light reflector

Abstract

In a light reflector equipped with a regular octahedral prism assembly as a light reflecting material, the degree to which the angle range in which light can be retroreflected is narrowed by the adapter is reduced. [Solution] The adapter comprises a joint portion having a cylindrical outer surface with a diameter shorter than the length of the diagonal in the octahedron shape of the prism assembly. The adapter has an insertion hole opening at one end of the joint portion into which an insertion vertex, which is one of the eight vertices of the octahedron shape, is inserted. In the insertion state, the insertion axis, which is the diagonal of the octahedron shape passing through the vertex of the insertion vertex, coincides with the central axis of the cylindrical shape. In addition, at least a portion of the area in each of the four light-transmitting surfaces surrounding the insertion vertex is exposed where the length of the perpendicular drawn from the insertion axis is equal to or shorter than the radius of the cylindrical shape.

Description

Technical Field

[0001] The present disclosure relates to an adapter and a light reflector.

Background Art

[0002] Conventionally, in the fields of surveying and motion analysis, light reflectors equipped with light reflecting materials have been used. The light reflector is attached to a surveying point or an object (such as a robot) to be analyzed for motion, and its position is optically derived from the reflected light from the light reflecting material. The light reflector often includes means for attaching the light reflecting material. When this attaching means is a device having a insertion hole for inserting the light reflecting material, this device may be called an "adapter".

[0003] The light reflecting material of the light reflector is often spherical. However, there is also a light reflector using a retroreflective prism having a right triangular pyramid shape with a regular triangular light transmitting surface (a triangular pyramid shape in which all three vertex angles surrounding one vertex are right angles) (in the present disclosure, this is called a "corner cube prism") as the light reflecting material so that the position can be derived even from a more distant position. For example, Patent Document 1 discloses a technique for enabling highly accurate position derivation regardless of the orientation of an object by combining eight corner cube prisms to form a regular octahedron shape and using the entire outer surface of the prism assembly as the light reflecting material.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Patent Document 1 makes no disclosure or suggestion whatsoever regarding "adapters." The mounting means for a light reflector using a regular octahedral shaped prism assembly as a light reflecting material, as disclosed in Patent Document 1, is configured to "attach a plane formed by cutting out one vertex of the prism assembly to the head of a bolt." In this configuration, the retroreflective prism (corner cube prism) on the bolt side has the portion constituting the above-mentioned plane as an additional reflective surface. In this case, depending on the angle of incidence of light, there is a risk that the retroreflection of light in the retroreflective prism may not occur correctly.

[0006] The above problem can be solved, for example, by using a light reflector in which one vertex of a prism assembly is inserted into an insertion hole provided at one end of a columnar adapter, and the overall shape is an intersecting shape of the adapter's columnar shape and the octahedron shape of the prism assembly (the three-dimensional shape formed by the outermost surfaces of multiple superimposed three-dimensional shapes). However, in the above intersecting shape light reflector, a problem arises in that a part of the light-transmitting surface of the prism assembly is covered by the adapter, narrowing the angular range in which the prism assembly can retroreflect light.

[0007] This disclosure provides a light reflector equipped with an octahedral shaped prism assembly as a light reflecting material, which makes it possible to reduce the degree to which the angle range in which light can be retroreflected is narrowed by the adapter. [Means for solving the problem]

[0008] According to one aspect of this disclosure, an adapter is provided that can be attached to a prism assembly. Here, the prism assembly is constructed by combining eight right-angled triangular pyramidal corner cube prisms, each having an equilateral triangular light-transmitting surface, to form a regular octahedron, and all of the outer surfaces of the regular octahedron are composed of light-transmitting surfaces. The adapter comprises a joint portion having a cylindrical outer surface with a diameter shorter than the length of the diagonal of the regular octahedron. The adapter also comprises an insertion hole opening at one end of the joint portion, into which an insertion vertex, which is one of the eight vertices of the regular octahedron, is inserted. In the insertion state, the insertion axis, which is the diagonal of the regular octahedron passing through the vertex of the insertion vertex, coincides with the central axis of the cylinder. Furthermore, at least a portion of each of the four light-transmitting surfaces surrounding the insertion vertex is exposed in a region where the length of the perpendicular dropped to the insertion axis is equal to or shorter than the radius of the cylinder.

[0009] According to the above aspects, in the intersection of the prism shape of the adapter and the octahedron shape of the prism assembly, a portion of the light-transmitting surface of the prism assembly, which would otherwise be covered by the prism shape, is exposed. This reduces the degree to which the adapter narrows the angular range in which light can retroreflect.

[0010] From another perspective, the outer periphery of one end of the joint is provided with four opposing edges and four missing sections. Here, the four opposing edges are set at four locations where the outer periphery faces the four ridges of the insertion top. The four missing sections are located between the four opposing edges, and a portion of the joint in the area described above is missing from the cylindrical outer surface toward the central axis.

[0011] Based on the above aspects, the angular range in which each corner cube prism on the adapter side of the prism assembly can retroreflect light can be extended towards the adapter side.

[0012] From another perspective, the missing portion exposes at least a portion of the four light-transmitting surfaces at the insertion top at four locations between the four opposing edges.

[0013] According to the above aspects, the range of light-transmitting surfaces that can retroreflect light in each corner cube prism on the adapter side of the prism assembly can be made wider by the absence of light.

[0014] From another perspective, at each of the four locations between the four opposing edges, the boundary line between the exposed area where the light-transmitting surface of the insertion top is exposed and the unexposed area where the light-transmitting surface is not exposed is convex toward the apex of the insertion top.

[0015] In the light-transmitting surface of a corner cube prism, the edges along the sides of its equilateral triangle shape have a narrower angular range in which light can be retroreflected than the central part surrounded by these edges. In contrast, the above-mentioned side view allows the exposure range of the light-transmitting surface at the insertion top to be biased towards the central part, thereby ensuring a wider angular range in which the prism assembly can retroreflect light.

[0016] In other aspects, the adapter comprises an adhesive portion that is attached to the four light-transmitting surfaces of the socket top with adhesive, and an inlet space provided around the apex of the socket top that allows for the inflow of adhesive and air.

[0017] Based on the above aspects, the adapter and the insertion top of the prism assembly can be integrated using adhesive. Furthermore, when bonding the adapter and the prism assembly, by allowing the adhesive and any gas trapped in the adhesive to escape into the intake space, the risk of the adhesive overflowing onto the exposed area of ​​the light-transmitting surface and causing problems with retroreflection of light can be reduced.

[0018] From another perspective, the aforementioned insertion hole is a closed hole. The side wall of this closed hole has a configuration comprising a rising portion that extends from the bottom of the hole, and an adhesive portion located at one end of this rising portion.

[0019] Based on the above aspects, the adapter inlet space can be defined as the space enclosed by the bottom and rising portion of the insertion hole.

[0020] From another perspective, a ventilation opening is formed in the central part of the bottom, connecting the bottom to the outside of the bottomed hole.

[0021] In the above configuration, when the adapter and the insertion top of the prism assembly are integrated with adhesive, the opening of the insertion hole is blocked by this insertion top. In contrast, according to the above side view, the gas released into the inflow space during the bonding of the adapter and the prism assembly can be released through the vent, thereby preventing backflow of this gas and adhesive towards the exposed area. Furthermore, by forming the vent in the central part of the bottom, which is relatively far from the bonding area in the insertion hole, the risk of this vent being blocked by the adhesive released into the inflow space can be reduced.

[0022] From another perspective, the adapter is equipped with air holes that connect the outer surface of the joint with the rising portion.

[0023] In the above configuration, when the adapter and the insertion top of the prism assembly are integrated with adhesive, the opening of the insertion hole is blocked by this insertion top. In contrast, according to the above side view, the gas released into the inlet space during the bonding of the adapter and the prism assembly can be released through the air hole, thereby preventing backflow of this gas and adhesive to the exposed area. Furthermore, by connecting the outer surface of the joint and the rising portion with an air hole, the air passage from the inlet space to the outside can be made shorter and simpler, making it easier for the gas to escape through the air hole.

[0024] According to another aspect, there is provided a light reflector including the adapter and the prism assembly as a light reflecting material. In this light reflector, the insertion top portion in the prism assembly is connected to the adapter in the inserted state.

[0025] According to the above aspect, it is possible to provide a light reflector utilizing the above-described adapter.

Advantages of the Invention

[0026] According to the present disclosure, in a light reflector including a prism assembly having a regular octahedron shape as a light reflecting material, it is possible to reduce the degree to which the angular range capable of retroreflecting light is narrowed by the adapter.

Brief Description of the Drawings

[0027] [Figure 1] It is a perspective view showing a light reflector 10 according to the first embodiment. [Figure 2] It is a plan view showing the light reflector 10 of FIG. 1, and the prism assembly 90 is represented by a virtual line. [Figure 3] It is a sectional view taken along the line III-III of FIG. 2, viewed in the direction of the arrow. [Figure 4] It is a perspective view showing a light reflector 20 according to the second embodiment. [Figure 5] It is a plan view showing the light reflector 20 of FIG. 2, and the prism assembly 90 is represented by a virtual line. [Figure 6] It is a sectional view taken along the line VI-VI of FIG. 5, viewed in the direction of the arrow. [Figure 7] It is a perspective view showing a light reflector 30 according to the third embodiment. [Figure 8] It is a plan view showing the light reflector 30 of FIG. 7, and the prism assembly 90 is represented by a virtual line. [Figure 9] It is a bottom view showing the light reflector 30 of FIG. 7. [Figure 10] It is a view taken in the direction of the arrow X of FIG. 8. [Figure 11] It is a sectional view taken along the line XI-XI of FIG. 8, viewed in the direction of the arrow. [Figure 12] Figure 8 is a cross-sectional view taken along the line XII-XII. [Modes for carrying out the invention]

[0028] The embodiments for implementing this disclosure will be described below with reference to the drawings. For convenience, in the following description, the directions "up" and "down" will be defined by defining "down" as the direction in which the prism assembly 90 (described later) is inserted into the adapter.

[0029] <First Embodiment> First, the configuration of the light reflector 10 according to the first embodiment will be described with reference to Figures 1 to 3. As shown in Figure 1, this light reflector 10 comprises a prism assembly 90 as a light reflecting material and an adapter 11.

[0030] The prism assembly 90 is composed of eight corner cube prisms 91. Each corner cube prism 91 is a right-angled triangular pyramidal retroreflective prism having an equilateral triangular light-transmitting surface 92. These corner cube prisms 91 are combined with their right-angled corners facing inward, forming a prism assembly 90 with a regular octahedron shape (hereinafter also simply referred to as "regular octahedron shape") in which all outer surfaces are composed of light-transmitting surfaces 92. The configuration of the prism assembly 90 itself is the same as that disclosed in Patent Document 1, and its properties regarding light reflection are also the same, so a detailed explanation is omitted here.

[0031] As shown in Figures 1 to 3, the adapter 11 comprises a joint portion 12 having a cylindrical outer surface 12A and an insertion hole 14 opened at one end 13 of the joint portion 12. The insertion hole 14 is formed in the shape of a regular square pyramid, with each side being an equilateral triangle. In this embodiment, the square of the base surface (the upper surface that constitutes the opening) of the regular square pyramid shape of the insertion hole 14 is inscribed within the cylindrical outer surface 12A (see Figure 2).

[0032] The insertion hole 14 connects the prism assembly 90 and the adapter 11 by being inserted into a socket, with one of the eight vertices 93 of the octahedron shape fitting into it. Hereinafter, the vertex 93 of the prism assembly 90 that is in the socket will also be referred to as the "insertion vertex 93A". Therefore, the above configuration can be rephrased as "the insertion vertex 93A of the prism assembly 90 is connected to the adapter 11 in an insertion state".

[0033] The insertion hole 14 is formed such that, when inserted, the vertex 14A corresponding to the vertex 93B of the insertion top 93A is located on the central axis 12B of the cylindrical shape formed by the outer surface 12A of the joint portion 12. Therefore, the insertion axis 90B of the prism assembly 90 coincides with the central axis 12B when inserted. Here, the insertion axis 90B is the diagonal line 90A that passes through the vertex 93B of the insertion top 93A, among the three diagonals 90A in the regular octahedron shape. In this embodiment, the length of the diagonal line 90A is longer than twice the radius 12C of the cylindrical shape formed by the outer surface 12A (i.e., the diameter) (see Figures 2 and 3).

[0034] In this embodiment, one end 13 of the joint portion 12 is formed in a planar shape, except for the portion forming the insertion hole 14. Therefore, when inserted, a portion of the area 91A (see Figure 3) is exposed on each of the four light-transmitting surfaces 92 surrounding the insertion top portion 93A, where the length of the perpendicular 90C drawn from the insertion shaft 90B is equal to or shorter than the radius 12C of the cylindrical shape formed by the outer surface 12A of the joint portion 12.

[0035] With the adapter 11 described above, in the intersecting shape (not shown) of the prism shape of the adapter and the octahedron shape of the prism assembly, a portion of the light-transmitting surface 92 of the prism assembly 90, which would otherwise be covered by the prism shape, is exposed. This reduces the degree to which the adapter 11 narrows the angular range in which the light reflector 10 can retroreflect light.

[0036] <Second Embodiment> Next, the configuration of the light reflector 20 according to the second embodiment will be described with reference to Figures 4 to 6. The light reflector 20 according to the second embodiment is an embodiment in which the adapter 11 of the light reflector 10 according to the first embodiment is replaced with an adapter 21. Therefore, parts or configurations common to those described above for the light reflector 10 (for example, each component of the prism assembly 90) will be assigned the same reference numerals as those used for those parts or configurations, and their detailed explanation will be omitted.

[0037] As shown in Figures 5 and 6, the light reflector 20 is constructed by attaching the insertion top portion 93A of the inserted prism assembly 90 to the attachment portion 24D of the adapter 21 with adhesive (not shown). With this configuration, the insertion top portion 93A of the prism assembly 90 is connected to the adapter 21 in the inserted state. The specific configuration of the attachment portion 24D will be described later, and a detailed explanation is omitted here.

[0038] The adapter 21 comprises a joint portion 22 having a cylindrical outer surface 22A and an insertion hole 24 opened at one end 23 of the joint portion 22. The insertion hole 24 is a bottomed hole opened in the center of one end 23. The insertion hole 24 is formed such that its center is located on the central axis 22B of the cylindrical shape of the outer surface 22A. The central axis 22B coincides with the insertion shaft 90B when inserted. In this embodiment, the length of the insertion shaft 90B (diagonal 90A) is longer than twice the radius 22C of the cylindrical shape formed by the outer surface 22A (i.e., the diameter) (see Figure 5).

[0039] As shown in Figures 5 and 6, the insertion hole 24 has a bottom portion 24A and a side wall 24B. The side wall 24B is configured to have a rising portion 24C that rises from the bottom portion 24A of the insertion hole 24, and an adhesive portion 24D provided at a position on one end 23 side of the rising portion 24C. In this embodiment, the bottom portion 24A is formed to form a square-shaped plane. The rising portion 24C rises perpendicularly to the bottom portion 24A and together with the bottom portion 24A forms a rectangular parallelepiped space 21A. The adhesive portion 24D is formed in the shape of a truncated square pyramid (a truncated pyramid shape in which two parallel bases are both square) with four sides forming an isosceles trapezoid shape, and fits with the four light-transmitting surfaces 92 of the insertion top portion 93A when inserted.

[0040] In this embodiment, the four sides of the square pyramidal shape of the adhesive portion 24D are each facing the four light-transmitting surfaces 92 of the insertion apex 93A, and these light-transmitting surfaces 92 are bonded together with an adhesive (not shown). During this bonding, the space 21A of the insertion hole 24 surrounds the apex 93B of the insertion apex 93A and functions as an inflow space that allows the inflow of adhesive and gas from the adhesive portion 24D side. Gases that may flow into the space 21A from the adhesive portion 24D side include, for example, air trapped in the insertion of the insertion apex 93A, gas from air bubbles mixed in the adhesive, or gas generated by the volatilization or chemical reaction of components of the adhesive.

[0041] An air hole 21B is formed in the rising portion 24C of the insertion hole 24, connecting this rising portion 24C with the outer surface of the joint portion 22. In this embodiment, the air hole 21B opens into one of the missing portions 23C, which are formed by chamfering a part of the outer peripheral edge 23A of one end 23 (chamfering that removes the edge of an object so that it forms an inclined surface at an angle greater than 45° with respect to the surface of the edge), allowing the gas that has flowed into the space 21A to escape to the outside. The specific configuration of the missing portion 23C will be described later, and a detailed explanation is omitted here.

[0042] As shown in Figure 5, the outer peripheral edge 23A of one end 23 of the joint portion 22 is provided with four opposing edges 23B and four missing portions 23C. Here, the four opposing edges 23B are set at four locations where the outer peripheral edge 23A faces the four ridges 93C of the insertion top portion 93A. The four missing portions 23C are set at four locations between the four opposing edges 23B.

[0043] As shown in Figure 6, each missing portion 23C is a part of the joint portion 22 located in a region 91A where the length of the perpendicular 90C drawn from the cylindrical central axis 22B (insertion shaft 90B) of the outer surface 22A is less than or equal to the radius 22C of the cylindrical shape. This absence is made from the outer surface 22A of the cylindrical shape toward its central axis 22B. In this embodiment, each missing portion 23C is formed by chamfering the outer peripheral edge 23A located between the opposing edge portions 23B with a "beveled edge".

[0044] The adapter 21 described above offers the same advantages as the adapter 11 described above.

[0045] Furthermore, the adapter 21 allows the angle range in which each corner cube prism 91 on the adapter 21 side of the prism assembly 90 can retroreflect light to be extended towards the adapter 21.

[0046] Furthermore, the adapter 21 allows the adapter 21 and the insertion top portion 93A of the prism assembly 90 to be integrated using adhesive. In other words, a light reflector 20 utilizing the adapter 21 can be provided. In addition, when bonding the adapter 21 and the prism assembly 90, the adhesive and any gas trapped in the adhesive can be released into space 21A, thereby reducing the risk of the adhesive overflowing onto the exposed area side of the light-transmitting surface 92 and causing problems with retroreflection of light.

[0047] Furthermore, with the adapter 21, the gas released into space 21A during bonding of the adapter 21 and the prism assembly 90 can be released through the air hole 21B, thereby suppressing the backflow of this gas and adhesive towards the exposed area. Also, with the configuration in which the outer surface of the joint portion 22 and the rising portion 24C are connected at the air hole 21B, the air passage from space 21A to the outside can be made shorter and simpler, making it easier for the gas to escape through the air hole 21B. Moreover, with the configuration in which the opening of the air hole 21B is opened in the missing portion 23C where a part of the joint portion 22 is missing, the air passage from space 21A to the outside can be made even shorter, making it even easier for the gas to escape through the air hole 21B.

[0048] <Third Embodiment> Next, the configuration of the light reflector 30 according to the third embodiment will be described using Figures 7 to 12. The light reflector 30 according to the third embodiment is an embodiment in which the adapter 11 of the light reflector 10 according to the first embodiment, or the adapter 21 of the light reflector 20 according to the second embodiment, is replaced with adapter 31. Therefore, parts or configurations common to those described above for the light reflector 10 or light reflector 20 (for example, each component of the prism assembly 90) will be assigned the same reference numerals as those used for those parts or configurations, and their detailed explanation will be omitted.

[0049] As shown in Figure 7, the light reflector 30 is constructed by attaching the insertion top portion 93A of the inserted prism assembly 90 to the attachment portion 34D of the adapter 31 with adhesive (not shown). With this configuration, the insertion top portion 93A of the prism assembly 90 is connected to the adapter 31 in the inserted state. The specific configuration of the attachment portion 34D will be described later, and a detailed explanation is omitted here.

[0050] As shown in Figures 9 to 12, the adapter 31 includes a joint portion 32 having a cylindrical outer surface 32A. This joint portion 32 has an insertion hole 34 (see Figure 11) opening at one upper end 33. The joint portion 32 also has a mounting structure at the end opposite to the end 33 (lower end) for attaching the light reflector 30 to its mounting object (not shown). In this embodiment, the joint portion 32 has a mounting structure consisting of a female thread 30A for screwing the adapter 31 and a pair of flattened portions 30B (see Figures 9 and 11) for making it easier to grip the cylindrical outer surface 32A. Note that "flattened portion" refers to a part of the curved surface of an object where the surface has a planar shape.

[0051] As shown in Figures 8, 11, and 12, the insertion hole 34 is a bottomed hole opened at one end 33, and is formed such that the center of the hole is located on the central axis 32B of the cylindrical shape of the outer surface 32A. The central axis 32B coincides with the insertion shaft 90B when inserted. In this embodiment, the length of the insertion shaft 90B is longer than twice the radius 32C of the cylindrical shape formed by the outer surface 32A (i.e., the diameter) (see Figure 8).

[0052] The insertion hole 34 has a bottom portion 34A and a side wall 34B. The side wall 34B is configured to have a rising portion 34C that rises from the bottom portion 34A of the insertion hole 34, and an adhesive portion 34D that is located on one end 33 side of the rising portion 34C.

[0053] The bottom portion 34A has a circular shape and is positioned such that its vertical position is the same as the apex 93B of the insertion top portion 93A when inserted. In this embodiment, a ventilation opening 31B is formed in the central part of the circular shape of the bottom portion 34A, which connects the bottom portion 34A with the space inside the female thread 30A. Here, the "space inside the female thread 30A" is the space outside the insertion hole 34, which opens at the lower end of the joint portion 32 and has a roughly cylindrical shape that is coaxial with the outer surface 32A of the joint portion 32.

[0054] The adhesive portion 34D has a configuration in which V-grooves are provided on four opposing edge portions 33B (see Figure 8) of the outer peripheral edge portion 33A of one end 33, which are opposite the four ridges 93C of the insertion top portion 93A. When inserted, it fits with the four ridges 93C. The four V-grooves of the adhesive portion 34D are bonded to the edges of the light-transmitting surface 92 along the ridges 93C by adhesive (not shown).

[0055] As shown in Figures 11 and 12, the rising portion 34C rises perpendicularly to the bottom portion 34A and together with the bottom portion 34A forms a cylindrical space 31A. When bonding the V-groove of the adhesive portion 34D with the edge of the light-transmitting surface 92, this space 31A surrounds the apex 93B of the insertion top portion 93A and functions as an inflow space that allows the inflow of adhesive and gas from the adhesive portion 24D side. Gases that may flow into space 31A from the adhesive portion 34D side include, for example, air trapped in the insertion of the insertion top portion 93A, gas from air bubbles mixed in the adhesive, or gas generated by the volatilization or chemical reaction of components of the adhesive.

[0056] As shown in Figure 8, four missing portions 33C are provided on the outer peripheral edge 33A of one end 33 of the joint portion 32, at four locations between the four opposing edge portions 33B. Each missing portion 33C is a part of the joint portion 32 that is missing in a region 91A where the length of the perpendicular 90C drawn from the central axis 32B (insertion shaft 90B) of the cylindrical shape of the outer surface 32A is less than or equal to the radius 32C of the cylindrical shape, as shown in Figure 10. This missing portion is made from the cylindrical outer surface 32A toward its central axis 32B. In this embodiment, each missing portion 33C is formed by applying a "spoon chamfer" (a chamfer that creates a recess with a circular or elliptical arc shape in cross-section on the surface of the object; see Figure 8) to the outer surface 32A located between the opposing edge portions 33B. The lower ends of these "spoon faces" are chamfered with a "miter face" perpendicular to the central axis 32B (a chamfer where the depth of the chamfer is made shallower at the edge or border of the chamfer to terminate the chamfered portion). As shown in Figure 12, the "miter face" of each missing portion 33C is positioned so that its vertical position is the same as the bottom portion 34A.

[0057] As shown in Figure 10, each missing portion 33C exposes a portion of the light-transmitting surface 92 adjacent to the missing portion 33C at the insertion top 93A. In other words, in the light reflector 30, the missing portion 33C of the adapter 31 exposes at least a portion of the four light-transmitting surfaces 92 at the insertion top 93A at four locations between the four opposing edge portions 33B. In Figure 10, the boundary line between the exposed area 92A where the light-transmitting surface 92 of the insertion top 93A is exposed and the unexposed area 92B where the light-transmitting surface 92 is not exposed is drawn as the "boundary line 92C". In this embodiment, each missing portion 33C is made to have a curved shape where the boundary line 92C is convex toward the vertex 93B of the insertion top 93A by chamfering its "spoon face".

[0058] The adapter 31 described above offers the same advantages as the adapter 11 described above.

[0059] Furthermore, the adapter 31 described above offers the same advantages as the adapter 21 described above.

[0060] Furthermore, the adapter 31 allows for a wider range of light-transmitting surfaces in each corner cube prism 91 on the adapter 31 side of the prism assembly 90, which can retroreflect light, to be secured by the missing portion 33C.

[0061] Furthermore, the adapter 31 allows the exposure range 92A on the light-transmitting surface 92 of the insertion top portion 93A to be biased towards the center of the equilateral triangular shape of the light-transmitting surface 92, thereby ensuring a wider angular range in which the prism assembly 90 can retroreflect light.

[0062] Furthermore, with the adapter 31, when the adapter 31 and the prism assembly 90 are bonded together, the gas released into space 31A is released through the vent 31B, thereby preventing backflow of this gas and adhesive towards the exposed area 92A. Also, by forming the vent 31B in the central part of the bottom 34A, which is relatively far from the bonding area 34D in the insertion hole 34, the risk of the vent 31B being blocked by the adhesive released into space 31A is reduced. Moreover, even if the bottom 34A of the insertion hole 34 and the apex 93B of the insertion top 93A are in the same vertical position, the apex 93B and the bottom 34A will not come into contact (interfere), so the depth of the insertion hole 34 can be made shallower, reducing the amount of work required to form the insertion hole 34.

[0063] <Other Embodiments> The embodiments for implementing this disclosure have been described above by the first to third embodiments. However, it will be apparent to those skilled in the art that various substitutions, modifications, and alterations are possible without departing from the purpose of this disclosure. That is, embodiments for implementing this disclosure may include all substitutions, modifications, and alterations that do not depart from the spirit and purpose of the claims attached to this specification. For example, the following various embodiments can be implemented as embodiments for implementing this disclosure.

[0064] (1) The adapter relating to this disclosure can be configured by appropriately combining the configurations of the first to third embodiments described above.

[0065] (2) In the adapter of this disclosure, the missing portion, which is a part of the joint, is not limited to the chamfer of the "rear-end chamfer" or a combination of the "spoon chamfer" and the "miter chamfer" described above. For example, in the second embodiment, the missing portion 23C (see Figure 6), which is a chamfer of the "rear-end chamfer" applied to the outer peripheral edge 23A of one end 23 of the joint 22, may be changed to a chamfer of an appropriate type, such as a corner chamfer (a surface inclined at a 45° angle with respect to the surface of the edge, sometimes called a "C-face"), a spoon chamfer, a buck chamfer (a surface in which the edge of the object is chamfered to create a concave angle of 270°), a bottom chamfer (a surface in which the edges on both sides of the "corner chamfer" are further chamfered to create a "miter chamfer"), or a rounded chamfer (a surface in which the edge of the object is chamfered to create a convex surface with a circular arc or elliptical arc cross-section). Similarly, in the third embodiment, the missing portion 33C (see Figure 7) on the outer surface 32A of the joint portion 22, which has a "spoon face" and a "mitre face" chamfer, may be changed to a chamfer of an appropriately selected type. In this case, the chamfer applied to the outer surface of the joint portion is preferably a chamfer that is concave toward the outer surface of the joint portion (convex toward the central axis of the joint portion), such as a spoon face, a buckle face, an inner rounded face (where the edges on both sides of the "spoon face" are further chamfered with a "buckle face"), or a bottom bevel face. With this shape of chamfer, the boundary line between the exposed area where the light-transmitting surface of the insertion top is exposed and the unexposed area where the light-transmitting surface is not exposed becomes convex toward the apex of the insertion top. Furthermore, the missing parts of this disclosure do not necessarily have to be formed by chamfering, but may be formed, for example, by additive manufacturing (a method of forming an object by stacking many layers that exhibit the cross-sectional shape of the object; widely used in so-called "3D printers"), a technique for integrally molding parts with irregularities such as die casting, or by combining multiple parts.

[0066] (3) In the adapter of this disclosure, the mounting structure provided in the joint portion is not limited to the "female thread" and "flat portion" described above, but can be changed as appropriate, for example, to a male thread, a clamp, or a flange for bonding or fastening.

[0067] (4) If the adapter of the present disclosure has an inlet space that allows adhesive to flow in when bonding the prism assembly, a vent or air hole that connects this inlet space to the outside may be omitted. In this case, bonding of the adapter and the prism assembly may be performed with an anaerobic adhesive. An "anaerobic adhesive" is an adhesive that hardens and exhibits adhesive strength in an environment where air is blocked, and is sometimes used for bonding optical components such as lenses and prisms. By configuring the adhesive inlet space to be blocked from the outside air, bonding of the adapter and the prism assembly with an anaerobic adhesive becomes possible. In this case, even if the anaerobic adhesive overflows onto the exposed area of ​​the light-transmitting surface, the overflowed anaerobic adhesive will not harden and can be wiped off and removed from the light-transmitting surface. [Explanation of Symbols]

[0068] 10 Light reflector 11 Adapters 12 Joint section 12A Outer surface 12B Center axis 12C radius 13 one end 14 insertion holes 14A Vertex 20 Light reflector 21 Adapters 21A Space (Inflow Space) 21B Air vent 22 Joint section 22A Outer surface 22B Center axis 22C radius 23 one end 23A Outer edge 23B Opposite edge 23C Missing part 24 Insertion holes (bottomed holes) 24A bottom 24B side wall 24C rising section 24D adhesive area 30 Light reflector 30A female thread 30B Flat section 31 Adapters 31A Space (Inflow Space) 31B Ventilation opening 32 Joint section 32A Outer surface 32B Center axis 32C radius 33 one end 33A Outer edge 33B Opposite edge 33C Missing part 34 Insertion holes (bottomed holes) 34A bottom 34B side wall 34C rising section 34D adhesive area 90 Prism Assembly 90A Diagonal 90B Insertion shaft 90C Perpendicular 91 Corner Cube Prism 91A area 92 Light transmission surface 92A Exposure range 92B Unexposed range 92C Border 93 Top 93A Plug-in top (top) 93B vertex 93C Ridge

Claims

1. An adapter to be attached to a prism assembly having a configuration in which eight right-angled triangular pyramidal corner cube prisms, each having an equilateral triangular light-transmitting surface, are combined to form a regular octahedron, and all of the outer surfaces of the regular octahedron are composed of the light-transmitting surfaces, A joint having a cylindrical outer surface with a diameter shorter than the length of the diagonal in the aforementioned regular octahedron shape, An insertion hole is provided at one end of the joint portion, into which one of the eight vertices of the regular octahedron shape, which is the insertion vertex, is inserted, Equipped with, In the aforementioned plugged-in state, The insertion axis, which is the diagonal of the regular octahedron shape passing through the vertex of the insertion top, coincides with the central axis of the cylindrical shape. In each of the four light-transmitting surfaces surrounding the insertion top, at least a portion of the region is exposed where the length of the perpendicular line drawn from the insertion axis is equal to or shorter than the radius of the cylindrical shape. adapter.

2. The adapter according to claim 1, On the outer peripheral edge of one end of the joint portion, The outer peripheral edge has four opposing edges set at four locations that face the four ridges of the insertion top, At four locations between the four opposing edges, extending from the outer surface of the cylindrical shape toward the central axis, there are four missing portions where a part of the joint portion in the region is missing, It is provided. adapter.

3. The adapter according to claim 2, Due to the aforementioned missing portion, at least a portion of the four light-transmitting surfaces at the insertion top is exposed at four locations between the four opposing edges. adapter.

4. The adapter according to claim 3, At each of the four locations between the four opposing edges, the boundary line between the exposed area where the light-transmitting surface of the insertion top is exposed and the unexposed area where the light-transmitting surface is not exposed is convex toward the apex of the insertion top. adapter.

5. The adapter according to claim 4, A part of the side wall of the insertion hole, located at a position on one end side of the apex of the insertion top in the insertion state, which faces the four light-transmitting surfaces of the insertion top in a plane and is attached to the light-transmitting surfaces with adhesive, In the aforementioned insertion state, an inflow space is provided at a position surrounding the apex of the insertion top, which allows the inflow of the adhesive and air, It is equipped with adapter.

6. The adapter according to claim 5, The aforementioned insertion hole is a closed hole, The side wall of the bottomed hole has a configuration comprising a rising portion that rises from the bottom of the bottomed hole and the adhesive portion provided at a position on one end side of the rising portion. adapter.

7. The adapter according to claim 6, A ventilation opening is formed in the central part of the bottom, which connects the bottom to the outside of the bottomed hole. adapter.

8. The adapter according to claim 6, It is provided with an air hole that connects the outer surface of the joint portion and the rising portion. adapter.

9. The invention comprises an adapter as described in any one of claims 1 to 8 and the prism assembly as a light reflecting material, The insertion top portion of the prism assembly is connected to the adapter in the inserted state. Light reflector.

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