EP4589194A1 - Light source device - Google Patents

Light source device

Info

Publication number
EP4589194A1
EP4589194A1 EP25151926.0A EP25151926A EP4589194A1 EP 4589194 A1 EP4589194 A1 EP 4589194A1 EP 25151926 A EP25151926 A EP 25151926A EP 4589194 A1 EP4589194 A1 EP 4589194A1
Authority
EP
European Patent Office
Prior art keywords
elongated hole
temperature
light source
lens
source device
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP25151926.0A
Other languages
German (de)
French (fr)
Inventor
Daisuke Matsuoka
Takayuki MOTOYANAGI
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyota Industries Corp
Original Assignee
Toyota Industries Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toyota Industries Corp filed Critical Toyota Industries Corp
Publication of EP4589194A1 publication Critical patent/EP4589194A1/en
Pending legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V17/00—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages
    • F21V17/10—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages characterised by specific fastening means or way of fastening
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V17/00—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages
    • F21V17/06—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages the fastening being onto or by the lampholder
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V17/00—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages
    • F21V17/10—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages characterised by specific fastening means or way of fastening
    • F21V17/12—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages characterised by specific fastening means or way of fastening by screwing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V5/00—Refractors for light sources
    • F21V5/007—Array of lenses or refractors for a cluster of light sources, e.g. for arrangement of multiple light sources in one plane
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V5/00—Refractors for light sources
    • F21V5/04—Refractors for light sources of lens shape
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2105/00—Planar light sources
    • F21Y2105/10—Planar light sources comprising a two-dimensional [2D] array of point-like light-generating elements
    • F21Y2105/14—Planar light sources comprising a two-dimensional [2D] array of point-like light-generating elements characterised by the overall shape of the two-dimensional [2D] array
    • F21Y2105/16—Planar light sources comprising a two-dimensional [2D] array of point-like light-generating elements characterised by the overall shape of the two-dimensional [2D] array square or rectangular, e.g. for light panels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]

Definitions

  • the present invention relates to a light source device.
  • the inner peripheral surface defining the elongated hole and the mounting screw interfere with each other in the width direction of the elongated hole. This may hinder the contraction of the lens, and thus deform the lens. If the lens is displaced or deformed, the lens is displaced in relation to the light source. In such a case, the lens may fail to achieve its intended light-gathering effect, potentially resulting in the light source unit being unable to meet the desired illuminance or the desired illumination range.
  • the substrate 11 is made of metal.
  • the substrate 11 of the present embodiment is made of aluminum.
  • the substrate 11 has a rectangular shape.
  • the substrate 11 includes internal thread holes 11a.
  • the internal thread holes 11a are disposed at the respective corners of the substrate 11.
  • the lens 13 is made of plastic.
  • the lens 13 of the present embodiment is made of silicone rubber.
  • the lens 13 has a rectangular plate portion 30.
  • the plate portion 30 has a first surface 30a and a second surface 30b.
  • the first surface 30a and the second surface 30b are surfaces orthogonal to the thickness direction of the plate portion 30.
  • the lens 13 includes substantially hemispherical protrusions 31, which protrude from the first surface 30a of the plate portion 30.
  • the number of the protrusions 31 is the same as the number of the light sources 12. That is, the lens 13 of the present embodiment has twelve protrusions 31.
  • the protrusions 31 are arranged in four rows in the longitudinal direction of the plate portion 30, and in three rows in the transverse direction of the plate portion 30. Each of the protrusions 31 corresponds to one of the light sources 12.
  • the lens 13 includes feet 32 protruding from the second surface 30b of the plate portion 30.
  • the feet 32 are provided at the respective corners of the plate portion 30.
  • the lens 13 includes holes 33.
  • the holes 33 are elongated holes 33.
  • the elongated holes 33 are through-holes that are formed through the lens 13 in the thickness direction of the plate portion 30.
  • the elongated holes 33 are provided at the respective corners of the plate portion 30. Therefore, the lens 13 of the present embodiment includes four elongated holes 33.
  • the four elongated holes 33 include a first elongated hole 33a, a second elongated hole 33b, a third elongated hole 33c, and a fourth elongated hole 33d. Details of the elongated holes 33 will be described later.
  • the lens 13 includes tubular bulging portions 34 projecting from the first surface 30a of the plate portion 30.
  • Each bulging portion 34 surrounds one of the elongated holes 33.
  • a space inside the bulging portion 34 communicates with the elongated hole 33.
  • the fasteners 14 are made of metal.
  • the fasteners 14 of the present embodiment are made of stainless steel.
  • the fasteners 14 of the present embodiment each include a bolt 41, a cylindrical collar 42, and a washer 43.
  • the bolt 41 has a columnar shaft 41a and a head 41b located at one end of the shaft 41a in the axial direction.
  • the shaft 41a has an external thread on the outer circumferential surface.
  • the shaft 41a is inserted through the washer 43 and then inserted through the collar 42.
  • the washer 43 is located between the head 41b and the collar 42.
  • the axial dimension of the collar 42 is substantially the same as the dimension from a distal end face 34a of the bulging portion 34 of the lens 13 to a distal end face 32a of the foot 32.
  • the outer diameter of the washer 43 is larger than the outer diameter of the head 41b of the bolt 41.
  • the lens 13 is disposed over the substrate 11.
  • the longitudinal direction and the transverse direction of the plate portion 30 are the same as the longitudinal direction and the transverse direction of the substrate 11, respectively.
  • the second surface 30b of the plate portion 30 faces the substrate 11.
  • each protrusion 31 overlaps with the corresponding light source 12.
  • the feet 32 create a clearance between the second surface 30b of the plate portion 30 and the light sources 12.
  • the fasteners 14 are inserted into the elongated holes 33 of the lens 13.
  • Each fastener 14 therefore includes an insertion portion 14a located inside the elongated hole 33.
  • the shaft 41a of the bolt 41 and the collar 42 are inserted into the elongated hole 33.
  • the insertion portion 14a of the present embodiment includes the collar 42 and a portion of the shaft 41a that is inserted in the elongated hole 33.
  • a first end face of the collar 42 in the axial direction is substantially flush with the distal end face 34a of the bulging portion 34.
  • a second end face of the collar 42 in the axial direction is in contact with the substrate 11.
  • the shaft 41a of the bolt 41 is screwed into the corresponding internal thread hole 11a of the substrate 11.
  • the lens 13 is thus fixed to the substrate 11 with the fasteners 14.
  • the washer 43 is sandwiched between the head 41b of the bolt 41 and a surface including the collar 42 and the bulging portion 34.
  • the distal end face 34a of the bulging portion 34 is a contact surface that contacts the washer 43.
  • the light source device 10 is designed for use not only in normal temperature environments but also in high-temperature or low-temperature environments. Further, the light sources 12 generate heat. Therefore, the ambient temperature inside the case 15 and the temperatures of the components inside the case 15 change.
  • the components inside the case 15 include the substrate 11, the lens 13, and the fasteners 14.
  • the ambient temperature inside the case 15, the temperature of the substrate 11, the temperature of the lens 13, and the temperature of the fasteners 14 are substantially the same.
  • the ambient temperature inside the case 15, the temperature of the substrate 11, the temperature of the lens 13, and the temperature of the fasteners 14 are collectively referred to as the temperature inside the case 15.
  • the temperature inside the case 15 when the light source device 10 is used in a normal-temperature environment is defined as a reference temperature.
  • the temperature inside the case 15 when the light source device 10 is used at the highest temperature in an intended operating temperature range of the light source device 10 is defined as a first temperature.
  • the temperature inside the case 15 when the light source device 10 is used at the lowest temperature in the intended operating temperature range of the light source device 10 is defined as a second temperature.
  • the first temperature is, for example, 80°C.
  • the second temperature is, for example, 0°C.
  • the reference temperature is a temperature between the first temperature and the second temperature.
  • the lens 13 is made of plastic. Therefore, when the temperature inside the case 15 changes, the lens 13 thermally expands or thermally contracts. When the temperature inside the case 15 increases, the lens 13 thermally expands. When the temperature inside the case 15 decreases, the lens 13 thermally contracts.
  • Fig. 3 shows the lens 13 when temperature inside the case 15 is the reference temperature.
  • Fig. 5 shows the lens 13 when the temperature inside the case 15 is the second temperature. Due to thermal contraction of the lens 13, the lens 13, when the temperature inside the case 15 is the second temperature, is slightly smaller than the lens 13 when the temperature inside the case 15 is the reference temperature.
  • the substrate 11 and the fasteners 14 are made of metal. Therefore, when the temperature inside the case 15 changes, the substrate 11 and the fasteners 14 are less likely to thermally expand or thermally contract than the lens 13. Therefore, when the temperature inside the case 15 deviates from the reference temperature, the lens 13 is displaced in relation to the substrate 11. When the lens 13 is displaced in relation to the substrate 11, the lens 13 is also displaced in relation to the light sources 12 fixed to the substrate 11. In the present embodiment, each protrusion 31 of the lens 13 is displaced in relation to each light source 12 fixed to the substrate 11.
  • the lens 13 is provided with a positioning point C.
  • the positioning point C is a point at which the position of the lens 13 in relation to the substrate 11 preferably remains unchanged even if the lens 13 thermally expands or thermally contracts.
  • the positioning point C is set at the center of the plate portion 30.
  • the center of the plate portion 30 is the intersection of the diagonals of the plate portion 30.
  • the elongated holes 33 are arranged around the positioning point C.
  • the first elongated hole 33a and the second elongated hole 33b are located on a first imaginary straight line L1, which passes through the positioning point C.
  • the positioning point C is located between the first elongated hole 33a and the second elongated hole 33b.
  • the third elongated hole 33c and the fourth elongated hole 33d are located on a second imaginary straight line L2, which passes through the positioning point C and intersects with the first imaginary straight line L1.
  • the positioning point C is located between the third elongated hole 33c and the fourth elongated hole 33d.
  • the first imaginary straight line L1 and the second imaginary straight line L2 coincide with the diagonal lines of the plate portion 30.
  • the first curved surface 331 is recessed away from the second curved surface 332.
  • the first curved surface 331 forms a part of the outer peripheral surface of a first imaginary cylinder C1.
  • the second curved surface 332 is recessed away from the first curved surface 331.
  • the second curved surface 332 forms a part of the outer peripheral surface of a second imaginary cylinder C2.
  • the diameter of the second imaginary cylinder C2 is larger than the diameter of the first imaginary cylinder C1.
  • the width of the width increasing portion 33e is at a minimum at the connection points between the first curved surface 331 and the two flat surfaces 333.
  • the width of the width increasing portion 33e is at a maximum at the connection points between the second curved surface 332 and the two flat surfaces 333.
  • the width of the width increasing portion 33e gradually increases from the connection points between the first curved surface 331 and the two flat surfaces 333 toward the connection points between the second curved surface 332 and the two flat surfaces 333.
  • dimensional tolerances are set for both the first dimension and the second dimension.
  • a minimum allowable dimension is defined for the first dimension, and a maximum allowable dimension is defined for the second dimension.
  • the minimum allowable dimension defined for the first dimension is set to be greater than the maximum allowable dimension defined for the second dimension. Therefore, the shortest distance D in each perpendicular direction between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a is greater than or equal to a minimum clearance obtained by subtracting the maximum allowable dimension defined for the second dimension from the minimum allowable dimension defined for the first dimension.
  • each elongated hole 33 is configured such that the shortest distance D in each perpendicular direction between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a is constant regardless of the temperature inside the case 15.
  • the lens 13 when the temperature inside the case 15 increases, the lens 13, which is made of plastic, thermally expands. In contrast, the substrate 11 and the fastener 14, which are made of metal, thermally expand negligibly.
  • the lens 13 includes the elongated holes 33, which extend in a radial pattern centered on the positioning point C. This structure allows the lens 13 to thermally expand in the extending direction of each elongated hole 33. The lens 13 moves relative to each fastener 14 so that the insertion portion 14a of the fastener 14 approaches the first curved surface 331 in the corresponding elongated hole 33.
  • each elongated hole 33 When the lens 13 thermally expands, the width of each elongated hole 33 also increases.
  • the elongated holes 33 of the present embodiment each have the width increasing portion 33e, in which the width of the elongated hole 33 increases as the distance from the positioning point C increases. Therefore, when the lens 13 thermally expands and each insertion portion 14a moves in the corresponding elongated hole 33 so as to approach the first curved surface 331, the insertion portion 14a moves to a narrower portion in the elongated hole 33.
  • the distance between the inner peripheral surface 330, which defines the elongated hole 33, and the insertion portion 14a of the fastener 14 is unlikely to increase. This suppresses the displacement of the lens 13 in the width direction of each elongated hole 33.
  • the lens 13 when the temperature inside the case 15 decreases, the lens 13, which is made of plastic, thermally contracts. In contrast, the substrate 11 and the fastener 14, which are made of metal, thermally expand negligibly.
  • the lens 13 includes the elongated holes 33, which extend in a radial pattern centered on the positioning point C. This structure allows the lens 13 to thermally contract in the extending direction of each elongated hole 33. The lens 13 moves relative to each fastener 14 so that the insertion portion 14a of the fastener 14 approaches the second curved surface 332 in the corresponding elongated hole 33.
  • the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a are less likely to interfere with each other. This suppresses the deformation of the lens 13 due to the hindrance of the contraction of the lens 13.
  • the lens 13 Since the displacement of the lens 13 and the deformation of the lens 13 are suppressed, the lens 13 is unlikely to be displaced in relation to the substrate 11. When the lens 13 is unlikely to be displaced in relation to the substrate 11, the lens 13 is also unlikely to be displaced in relation to the light sources 12 fixed to the substrate 11. Consequently, even if the lens 13 thermally expands or thermally contracts, the light source device 10 readily achieves the desired illuminance and the desired illumination range.
  • the present embodiment has the following advantages.
  • This configuration allows for thermal expansion of the lens 13 in which a portion of the lens 13 away from the positioning point C toward the third elongated hole 33c and a portion of the lens 13 away from the positioning point C toward the fourth elongated hole 33d move away from each other in the extending direction of the second imaginary straight line L2.
  • This configuration also allows for thermal contraction of the lens 13 in which a portion of the lens 13 away from the positioning point C toward the third elongated hole 33c and a portion of the lens 13 away from the positioning point C toward the fourth elongated hole 33d approach each other in the extending direction of the second imaginary straight line L2. The configuration thus suppresses the displacement of the positioning point C in the extending direction of the second imaginary straight line L2.
  • Movements in the extending direction of the first imaginary straight line L1 of the fasteners 14 inserted into the first elongated hole 33a and the second elongated hole 33b are restricted by the contact of the fasteners 14 inserted into the third elongated hole 33c and the fourth elongated hole 33d with the inner peripheral surfaces 330 that define the corresponding elongated holes 33. This restricts the displacement of the lens 13 in the extending direction of the first imaginary straight line L1.
  • Movements in the extending direction of the second imaginary straight line L2 of the fasteners 14 inserted into the third elongated hole 33c and the fourth elongated hole 33d are restricted by the contact of the fasteners 14 inserted into the first elongated hole 33a and the second elongated hole 33b with the inner peripheral surfaces 330 that define the corresponding elongated holes 33. This restricts the displacement of the lens 13 in the extending direction of the second imaginary straight line L2.
  • Each fastener 14 includes the collar 42.
  • the first end face of the collar 42 in the axial direction is substantially flush with the distal end face 34a of the bulging portion 34 of the lens 13. This limits deformation of the lens 13 when the bolts 41 are tightened.
  • Each fastener 14 includes the washer 43.
  • the outer diameter of the washer 43 is larger than the outer diameter of the head 41b of the bolt 41.
  • the washer 43 is disposed between the head 41b of the bolt 41 and the surface including the first end face of the collar 42 in the axial direction and the distal end face 34a of the bulging portion 34. This configuration increases the pressing area of the bulging portion 34 by the fastener 14.
  • the fixing member or the base member is not limited to the substrate 11.
  • the fixing member or the base member may be a metal component different from the substrate 11.
  • the fixing member or the base member may be a heat sink.
  • the fixing member or the base member may be the case 15.
  • the fixing member or the base member is a metal member different from the substrate 11, the light source 12 is fixed to the fixing member or the base member via the substrate 11 by fixing the substrate 11, to which the light source 12 is fixed, to the fixing member or the base member.
  • the fasteners for fixing the substrate 11, to which the light source 12 is fixed, to the fixing member or the base member may be the same as or different from the fasteners 14 for fixing the lens 13 to the fixing member or the base member.
  • the substrate 11 and the light source 12 must be fixed so as not to be displaced in relation to the fixing member or the base member even when the temperature inside the case 15 changes.
  • the substrate 11 may include through-holes instead of the internal thread holes 11a.
  • the lens 13 and the substrate 11 may be fastened to each other by screwing the bolts 41, which are inserted into the elongated holes 33 of the lens 13 and the through-holes of the substrate 11, into nuts.
  • the light sources 12 are not limited to LEDs.
  • the light sources 12 may be other light sources such as halogen lamps.
  • the number of light sources 12 may be changed.
  • the fasteners 14 do not necessarily need to include the collars 42.
  • the washer 43 preferably covers the entire distal end face 34a of the bulging portion 34 in the width direction of the elongated hole 33. In this case, when the bolt 41 is tightened, the washer 43 is unlikely to sink into the bulging portion 34.
  • each fastener 14 may include a pin that protrudes from the fixing member and has an external thread on the outer peripheral surface thereof. The pin is inserted into each elongated hole 33 of the lens 13 and then screwed into the nut.
  • the positioning point C is not limited to the center of the plate portion 30.
  • the positioning point C may be set at any position on the lens 13.
  • the positioning point C is set at the center of that protrusion 31.
  • the shape of the substrate 11 is not limited to a rectangle.
  • the substrate 11 may have, for example, a square shape or a circular shape.
  • the shape of the plate portion 30 of the lens 13 is not limited to a rectangle.
  • the plate portion 30 may have, for example, a square shape or a circular shape.
  • the shape of the plate portion 30 may be different from the shape of the substrate 11.
  • the size of the plate portion 30 may be different from the size of the substrate 11.
  • the number of the elongated holes 33 provided in the lens 13 is not limited to four.
  • the number of elongated holes 33 provided in the lens 13 may be changed.
  • At least one of the holes arranged around the positioning point C may be an elongated hole 33.
  • One of the first elongated hole 33a and the second elongated hole 33b may be replaced by a round hole.
  • One of the third elongated hole 33c and the fourth elongated hole 33d may be replaced by round hole.
  • the elongated holes 33 are provided at the respective corners of the plate portion 30, but the arrangement of the elongated holes 33 is not limited thereto.
  • the first imaginary straight line L1 may be an imaginary straight line that passes through the positioning point C and extends in the longitudinal direction of the plate portion 30.
  • the second imaginary straight line L2 may be an imaginary straight line that passes through the positioning point C and extends in the transverse direction of the plate portion 30.
  • the shortest distance D in each perpendicular direction between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a may be less than the minimum clearance obtained by subtracting the maximum allowable dimension defined for the second dimension from the minimum allowable dimension defined for the first dimension.
  • the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a may be in contact with each other.
  • the shortest distance D in each perpendicular direction between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a does not necessarily remain the same at the reference temperature, at the first temperature, and at the second temperature inside the case 15. In other words, the distance between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a does not necessarily need to be constant regardless of the temperature of the lens 13.
  • the inner peripheral surface 330 which defines the elongated hole 33, does not necessarily need to include the first curved surface 331, the second curved surface 332, and the two flat surfaces 333. As long as the elongated hole 33 includes the width increasing portion 33e, the shape of the elongated hole 33 may be changed.
  • the insertion portion 14a of each fastener 14 does not necessarily need to have a cylindrical shape. The shape of the insertion portion 14a may be changed according to the shape of the elongated hole 33.
  • the elongated hole 33 and the insertion portion 14a are formed such that the insertion portion 14a does not interfere with the first curved surface 331 when the temperature inside the case 15 is the first temperature, and the insertion portion 14a does not interfere with the second curved surface 332 when the temperature inside the case 15 is the second temperature.
  • the elongated hole 33 may have a trapezoidal shape
  • the insertion portion 14a may have a prismatic shape with a trapezoidal cross-section when cut in a plane perpendicular to the thickness direction of the lens 13.
  • the first curved surface 331 and the second curved surface 332 are replaced by flat surfaces.
  • the outer peripheral surface 140 of the insertion portion 14a has two facing surfaces 140a extending parallel to the two flat surfaces 333. This configuration increases the size of the surface of the outer peripheral surface 140 of the insertion portion 14a that is located at a position separated, in the perpendicular direction, by the shortest distances D from the inner peripheral surface 330, which defines the elongated hole 33.
  • the dimension of the elongated hole 33 in the extending direction may be longer than the dimension of the elongated hole 33 in the extending direction in the above-described embodiment, which is indicated by the broken lines in Fig. 10 .
  • the two flat surfaces 333 may be extended toward the positioning point C, so that the first curved surface 331 is located closer to the positioning point C than the first curved surface 331 of the above-described embodiment.
  • the second curved surface 332 may be located closer to the edge of the lens 13 than the second curved surface 332 of the above-described embodiment.
  • the lens 13 expands or contracts due to temperature changes in the case 15.
  • the lens 13 may expand or contract due to a factor other than temperature changes.
  • the lens 13 made of an organic plastic such as silicone rubber may swell due to contact with a solvent or the like.
  • the lens 13 may expand due to moisture absorption or water absorption.
  • the lens 13 may contract due to age-related degradation, such as an increase in hardness or a decrease in weight.
  • This configuration also accommodates expansion or contraction of the lens 13 caused by factors other than temperature changes.
  • the elongated hole 33 is designed considering the expected states of the lens 13 during expansion and contraction.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)
  • Lens Barrels (AREA)
  • Cameras Adapted For Combination With Other Photographic Or Optical Apparatuses (AREA)
  • Securing Globes, Refractors, Reflectors Or The Like (AREA)

Abstract

A light source device includes a metal substrate, a light source fixed to the substrate, and a plastic lens fixed to the substrate with a metal fastener. The lens is provided with an elongated hole through which the fastener is inserted. The elongated hole extends in a radial pattern centered on a specified positioning point defined in the lens. The elongated hole includes a width increasing portion in which a width of the elongated hole increases as a distance from the positioning point increases.

Description

    BACKGROUND 1. Field
  • The present invention relates to a light source device.
    • 2. Description of Related Art
  • The light source unit disclosed in Japanese Laid-Open Patent Publication No. 2019-102389 includes a metal support member, a light source fixed to the support member, and a silicone lens fixed to the support member by mounting screws. The silicone lens is provided with an elongated hole through which a mounting screw is inserted.
  • The lens expands or contracts due to various factors. For example, lenses expand or contract in response to temperature changes. Specifically, when the light source unit is used in a high-temperature environment or when the light source generates heat, the lens thermally expands. When the lens expands, the width of the elongated hole increases. As a result, the distance in the width direction of the elongated hole between the inner peripheral surface defining the elongated hole and the mounting screw increases, making it more likely for the lens to be displaced in the width direction of the elongated hole. Conversely, when the light source unit is used in a low-temperature environment, the lens thermally contracts. When the lens contracts, the width of the elongated hole decreases. As a result, the inner peripheral surface defining the elongated hole and the mounting screw interfere with each other in the width direction of the elongated hole. This may hinder the contraction of the lens, and thus deform the lens. If the lens is displaced or deformed, the lens is displaced in relation to the light source. In such a case, the lens may fail to achieve its intended light-gathering effect, potentially resulting in the light source unit being unable to meet the desired illuminance or the desired illumination range.
    • SUMMARY
  • This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
  • In one general aspect, a light source device includes a metal fixing member, a light source fixed to the fixing member, and a plastic lens fixed to the fixing member with a metal fastener. The lens is provided with an elongated hole through which the fastener is inserted. The elongated hole extends in a radial pattern centered on a specified positioning point defined in the lens. The elongated hole includes a width increasing portion in which a width of the elongated hole increases as a distance from the positioning point increases.
  • Other features and aspects will be apparent from the following detailed description, the drawings, and the claims.
    • BRIEF DESCRIPTION OF THE DRAWINGS
    • Fig. 1 is a side view of a light source device.
    • Fig. 2 is an exploded perspective view of the light source device.
    • Fig. 3 is a cross-sectional view of the light source device when the temperature inside the case is a reference temperature.
    • Fig. 4 is a cross-sectional view of the light source device when the temperature inside the case is a first temperature.
    • Fig. 5 is a cross-sectional view of the light source device when the temperature inside the case is a second temperature.
    • Fig. 6 is an enlarged view of an elongated hole when the temperature inside the case is the reference temperature.
    • Fig. 7 is an enlarged view of an elongated hole when the temperature inside the case is the first temperature.
    • Fig. 8 is an enlarged view of an elongated hole when the temperature inside the case is the second temperature.
    • Fig. 9 is a cross-sectional view showing an elongated hole and an insertion portion of a fastener according to a modification.
    • Fig. 10 is a cross-sectional view showing an elongated hole according to a modification.
  • Throughout the drawings and the detailed description, the same reference numerals refer to the same elements. The drawings may not be to scale, and the relative size, proportions, and depiction of elements in the drawings may be exaggerated for clarity, illustration, and convenience.
    • DETAILED DESCRIPTION
  • This description provides a comprehensive understanding of the methods, apparatuses, and/or systems described. Modifications and equivalents of the methods, apparatuses, and/or systems described are apparent to one of ordinary skill in the art. Sequences of operations are exemplary, and may be changed as apparent to one of ordinary skill in the art, with the exception of operations necessarily occurring in a certain order. Descriptions of functions and constructions that are well known to one of ordinary skill in the art may be omitted.
  • Exemplary embodiments may have different forms, and are not limited to the examples described. However, the examples described are thorough and complete, and convey the full scope of the disclosure to one of ordinary skill in the art.
  • In this specification, "at least one of A and B" should be understood to mean "only A, only B, or both A and B."
  • An embodiment according to the present invention will now be described with reference to Figs. 1 to 8.
    • Light Source Device
  • As shown in Figs. 1 and 2, a light source device 10 includes a substrate 11, which is a fixing member or a base member, light sources 12, a lens 13, fasteners 14, and a case 15. Although not illustrated, the light source device 10 includes a drive circuit that drives the light sources 12. The substrate 11, the light sources 12, the lens 13, the fasteners 14, and the drive circuit are accommodated in the case 15. The case 15 is provided with a window (not shown) for transmitting light to the outside of the case 15.
  • The substrate 11 is made of metal. The substrate 11 of the present embodiment is made of aluminum. The substrate 11 has a rectangular shape. The substrate 11 includes internal thread holes 11a. The internal thread holes 11a are disposed at the respective corners of the substrate 11.
  • The light sources 12 of the present embodiment are light-emitting diodes (LEDs). The light sources 12 are fixed to the substrate 11. In the present embodiment, the light sources 12 are arranged in four rows in the longitudinal direction of the substrate 11, and in three rows in the transverse direction of the substrate 11. Therefore, the light source device 10 of the present embodiment includes twelve light sources 12.
  • The lens 13 is made of plastic. The lens 13 of the present embodiment is made of silicone rubber. The lens 13 has a rectangular plate portion 30. The plate portion 30 has a first surface 30a and a second surface 30b. The first surface 30a and the second surface 30b are surfaces orthogonal to the thickness direction of the plate portion 30.
  • The lens 13 includes substantially hemispherical protrusions 31, which protrude from the first surface 30a of the plate portion 30. The number of the protrusions 31 is the same as the number of the light sources 12. That is, the lens 13 of the present embodiment has twelve protrusions 31. The protrusions 31 are arranged in four rows in the longitudinal direction of the plate portion 30, and in three rows in the transverse direction of the plate portion 30. Each of the protrusions 31 corresponds to one of the light sources 12.
  • The lens 13 includes feet 32 protruding from the second surface 30b of the plate portion 30. The feet 32 are provided at the respective corners of the plate portion 30.
  • As shown in Fig. 3, the lens 13 includes holes 33. The holes 33 are elongated holes 33. The elongated holes 33 are through-holes that are formed through the lens 13 in the thickness direction of the plate portion 30. The elongated holes 33 are provided at the respective corners of the plate portion 30. Therefore, the lens 13 of the present embodiment includes four elongated holes 33. The four elongated holes 33 include a first elongated hole 33a, a second elongated hole 33b, a third elongated hole 33c, and a fourth elongated hole 33d. Details of the elongated holes 33 will be described later.
  • As shown in Figs. 1 and 2, the lens 13 includes tubular bulging portions 34 projecting from the first surface 30a of the plate portion 30. Each bulging portion 34 surrounds one of the elongated holes 33. A space inside the bulging portion 34 communicates with the elongated hole 33.
  • The fasteners 14 are made of metal. The fasteners 14 of the present embodiment are made of stainless steel. The fasteners 14 of the present embodiment each include a bolt 41, a cylindrical collar 42, and a washer 43. The bolt 41 has a columnar shaft 41a and a head 41b located at one end of the shaft 41a in the axial direction. The shaft 41a has an external thread on the outer circumferential surface. The shaft 41a is inserted through the washer 43 and then inserted through the collar 42. The washer 43 is located between the head 41b and the collar 42. The axial dimension of the collar 42 is substantially the same as the dimension from a distal end face 34a of the bulging portion 34 of the lens 13 to a distal end face 32a of the foot 32. The outer diameter of the washer 43 is larger than the outer diameter of the head 41b of the bolt 41.
  • As shown in Fig. 1, the lens 13 is disposed over the substrate 11. The longitudinal direction and the transverse direction of the plate portion 30 are the same as the longitudinal direction and the transverse direction of the substrate 11, respectively. The second surface 30b of the plate portion 30 faces the substrate 11. In the thickness direction of the substrate 11 and the plate portion 30, each protrusion 31 overlaps with the corresponding light source 12. The feet 32 create a clearance between the second surface 30b of the plate portion 30 and the light sources 12.
  • The fasteners 14 are inserted into the elongated holes 33 of the lens 13. Each fastener 14 therefore includes an insertion portion 14a located inside the elongated hole 33. In the present embodiment, the shaft 41a of the bolt 41 and the collar 42 are inserted into the elongated hole 33. Accordingly, the insertion portion 14a of the present embodiment includes the collar 42 and a portion of the shaft 41a that is inserted in the elongated hole 33. A first end face of the collar 42 in the axial direction is substantially flush with the distal end face 34a of the bulging portion 34. A second end face of the collar 42 in the axial direction is in contact with the substrate 11. The shaft 41a of the bolt 41 is screwed into the corresponding internal thread hole 11a of the substrate 11. The lens 13 is thus fixed to the substrate 11 with the fasteners 14. The washer 43 is sandwiched between the head 41b of the bolt 41 and a surface including the collar 42 and the bulging portion 34. The distal end face 34a of the bulging portion 34 is a contact surface that contacts the washer 43.
  • The light source device 10 is designed for use not only in normal temperature environments but also in high-temperature or low-temperature environments. Further, the light sources 12 generate heat. Therefore, the ambient temperature inside the case 15 and the temperatures of the components inside the case 15 change. The components inside the case 15 include the substrate 11, the lens 13, and the fasteners 14. The ambient temperature inside the case 15, the temperature of the substrate 11, the temperature of the lens 13, and the temperature of the fasteners 14 are substantially the same. Hereinafter, the ambient temperature inside the case 15, the temperature of the substrate 11, the temperature of the lens 13, and the temperature of the fasteners 14 are collectively referred to as the temperature inside the case 15. The temperature inside the case 15 when the light source device 10 is used in a normal-temperature environment is defined as a reference temperature. The temperature inside the case 15 when the light source device 10 is used at the highest temperature in an intended operating temperature range of the light source device 10 is defined as a first temperature. The temperature inside the case 15 when the light source device 10 is used at the lowest temperature in the intended operating temperature range of the light source device 10 is defined as a second temperature. The first temperature is, for example, 80°C. The second temperature is, for example, 0°C. The reference temperature is a temperature between the first temperature and the second temperature.
  • As described above, the lens 13 is made of plastic. Therefore, when the temperature inside the case 15 changes, the lens 13 thermally expands or thermally contracts. When the temperature inside the case 15 increases, the lens 13 thermally expands. When the temperature inside the case 15 decreases, the lens 13 thermally contracts.
  • Fig. 3 shows the lens 13 when temperature inside the case 15 is the reference temperature.
  • Fig. 4 shows the lens 13 when the temperature inside the case 15 is the first temperature. Due to thermal expansion of the lens 13, the lens 13, when the temperature inside the case 15 is the first temperature, is slightly larger than the lens 13 when the temperature inside the case 15 is the reference temperature.
  • Fig. 5 shows the lens 13 when the temperature inside the case 15 is the second temperature. Due to thermal contraction of the lens 13, the lens 13, when the temperature inside the case 15 is the second temperature, is slightly smaller than the lens 13 when the temperature inside the case 15 is the reference temperature.
  • The substrate 11 and the fasteners 14 are made of metal. Therefore, when the temperature inside the case 15 changes, the substrate 11 and the fasteners 14 are less likely to thermally expand or thermally contract than the lens 13. Therefore, when the temperature inside the case 15 deviates from the reference temperature, the lens 13 is displaced in relation to the substrate 11. When the lens 13 is displaced in relation to the substrate 11, the lens 13 is also displaced in relation to the light sources 12 fixed to the substrate 11. In the present embodiment, each protrusion 31 of the lens 13 is displaced in relation to each light source 12 fixed to the substrate 11.
  • As shown in Fig. 3, the lens 13 is provided with a positioning point C. The positioning point C is a point at which the position of the lens 13 in relation to the substrate 11 preferably remains unchanged even if the lens 13 thermally expands or thermally contracts. In the present embodiment, the positioning point C is set at the center of the plate portion 30. The center of the plate portion 30 is the intersection of the diagonals of the plate portion 30.
    • Elongated Holes
  • The elongated holes 33 will now be described.
  • The elongated holes 33 are arranged around the positioning point C. The first elongated hole 33a and the second elongated hole 33b are located on a first imaginary straight line L1, which passes through the positioning point C. The positioning point C is located between the first elongated hole 33a and the second elongated hole 33b. The third elongated hole 33c and the fourth elongated hole 33d are located on a second imaginary straight line L2, which passes through the positioning point C and intersects with the first imaginary straight line L1. The positioning point C is located between the third elongated hole 33c and the fourth elongated hole 33d. In the present embodiment, the first imaginary straight line L1 and the second imaginary straight line L2 coincide with the diagonal lines of the plate portion 30.
  • The elongated holes 33 extend in a radial pattern centered on the positioning point C. Each of the elongated holes 33 includes a width increasing portion 33e, in which the width of the elongated hole 33 increases as the distance from the positioning point C increases. The width of the elongated hole 33 is a dimension of the elongated hole 33 in the width direction, which is orthogonal to both the extending direction of the elongated hole 33 and the direction in which the elongated hole 33 is formed through the lens 13.
  • Each of the first elongated hole 33a and the second elongated hole 33b has a line-symmetrical shape with respect to the first imaginary straight line L1 in the width direction of the first elongated hole 33a and the second elongated hole 33b. Each of the third elongated hole 33c and the fourth elongated hole 33d has a line-symmetrical shape with respect to the second imaginary straight line L2 in the width direction of the third elongated hole 33c and the fourth elongated hole 33d.
  • As shown in Fig. 6, an inner peripheral surface 330 defining each elongated hole 33 of the present embodiment includes a first curved surface 331, a second curved surface 332, and two flat surfaces 333. When the elongated hole 33 is viewed from the thickness direction of the plate portion 30, the first curved surface 331 and the second curved surface 332 face each other in the extending direction of the elongated hole 33. The first curved surface 331 is located closer to the positioning point C than the second curved surface 332. The two flat surfaces 333 face each other in the width direction of the elongated hole 33.
  • The first curved surface 331 is recessed away from the second curved surface 332. The first curved surface 331 forms a part of the outer peripheral surface of a first imaginary cylinder C1. The second curved surface 332 is recessed away from the first curved surface 331. The second curved surface 332 forms a part of the outer peripheral surface of a second imaginary cylinder C2. The diameter of the second imaginary cylinder C2 is larger than the diameter of the first imaginary cylinder C1.
  • One of the two flat surfaces 333 connects one end of the first curved surface 331 and one end of the second curved surface 332, and the other flat surface 333 connects the other end of the first curved surface 331 and the other end of the second curved surface 332. The two flat surfaces 333 form two common external tangents L that externally contact the first imaginary cylinder C1 and the second imaginary cylinder C2. The distance between the two flat surfaces 333 gradually increases as the distance from the positioning point C increases in the extending direction of the elongated hole 33. The width increasing portion 33e is formed by a space located between the two flat surfaces 333. In other words, the flat surfaces 333 define the width increasing portion 33e.
  • The width of the width increasing portion 33e is at a minimum at the connection points between the first curved surface 331 and the two flat surfaces 333. The width of the width increasing portion 33e is at a maximum at the connection points between the second curved surface 332 and the two flat surfaces 333. The width of the width increasing portion 33e gradually increases from the connection points between the first curved surface 331 and the two flat surfaces 333 toward the connection points between the second curved surface 332 and the two flat surfaces 333.
  • Fig. 6 shows the elongated hole 33 when the temperature inside the case 15 is the reference temperature. At this time, the insertion portion 14a of the fastener 14 is located substantially at the center in the extending direction of the elongated hole 33.
  • Fig. 7 shows the elongated hole 33 when the temperature inside the case 15 is the first temperature. As described above, when the temperature inside the case 15 increases, the lens 13 thermally expands. At this time, since the entire lens 13 expands, the width of the elongated hole 33 increases, accordingly.
  • Fig. 8 shows the elongated hole 33 when the temperature inside the case 15 is the second temperature. As described above, when the temperature inside the case 15 decreases, the lens 13 thermally contracts. At this time, since the entire lens 13 thermally contracts, the width of the elongated hole 33 decreases, accordingly.
  • As shown in Figs. 3 to 5, a center O of the insertion portion 14a inserted into the first elongated hole 33a and a center O of the insertion portion 14a inserted into the second elongated hole 33b are both located on the first imaginary straight line L1. A center O of the insertion portion 14a inserted into the third elongated hole 33c and a center O of the insertion portion 14a inserted into the fourth elongated hole 33d are both located on the second imaginary straight line L2. In the present embodiment, the center O of each insertion portion 14a coincides with the axis of the shaft 41a.
  • As shown in Figs. 6 to 8, a direction along a perpendicular line T extending from the center O of the insertion portion 14a of the fastener 14 toward each of the flat surfaces 333, which define the width increasing portion 33e, is defined as a perpendicular direction. In the present embodiment, when the temperature inside the case 15 is the first temperature, the intersection between each perpendicular line T and the corresponding flat surface 333 agrees with the connection point between the first curved surface 331 and the flat surface 333. When the temperature inside the case 15 is the second temperature, the intersection point between each perpendicular line T and the corresponding flat surface 333 agrees with the connection point between the second curved surface 332 and the flat surface 333.
  • The minimum of the distance in each perpendicular direction between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a is referred to as a shortest distance D. The dimension in each perpendicular direction from the center O of the insertion portion 14a to the inner peripheral surface 330, which defines the elongated hole 33, is referred to as a first dimension. The dimension in each perpendicular direction from the center O of the insertion portion 14a to the outer peripheral surface 140 of the insertion portion 14a is referred to as a second dimension. The shortest distance D is obtained by subtracting the second dimension from the first dimension. In other words, the first dimension is obtained by adding the second dimension to the shortest distance D. In the present embodiment, the second dimension agrees with the radius of the insertion portion 14a.
  • In the present embodiment, each elongated hole 33 is configured such that a clearance exists between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a at the position where the insertion portion 14a of the fastener 14 is located in the elongated hole 33. Specifically, if the first dimension is greater than the second dimension, a clearance is created between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a.
  • In practice, dimensional tolerances are set for both the first dimension and the second dimension. A minimum allowable dimension is defined for the first dimension, and a maximum allowable dimension is defined for the second dimension. The minimum allowable dimension defined for the first dimension is set to be greater than the maximum allowable dimension defined for the second dimension. Therefore, the shortest distance D in each perpendicular direction between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a is greater than or equal to a minimum clearance obtained by subtracting the maximum allowable dimension defined for the second dimension from the minimum allowable dimension defined for the first dimension.
  • In the present embodiment, each elongated hole 33 is configured such that the shortest distance D in each perpendicular direction between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a is constant regardless of the temperature inside the case 15.
  • Specifically, as shown in Fig. 6, the shortest distance D when the temperature inside the case 15 is the reference temperature is set to a specified distance Da. As shown in Fig. 7, the shortest distance D when the temperature inside the case 15 is the first temperature is set to the specified distance Da. Further, as shown in Fig. 8, the shortest distance D when the temperature inside the case 15 is the second temperature is set to the specified distance Da. The shortest distance D in each perpendicular direction between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a remains the same at the reference temperature, at the first temperature, and at the second temperature inside the case 15.
    • Operation of the Present Embodiment
  • The operation of the present embodiment will now be described.
  • As shown in Fig. 7, when the temperature inside the case 15 increases, the lens 13, which is made of plastic, thermally expands. In contrast, the substrate 11 and the fastener 14, which are made of metal, thermally expand negligibly. In the present embodiment, the lens 13 includes the elongated holes 33, which extend in a radial pattern centered on the positioning point C. This structure allows the lens 13 to thermally expand in the extending direction of each elongated hole 33. The lens 13 moves relative to each fastener 14 so that the insertion portion 14a of the fastener 14 approaches the first curved surface 331 in the corresponding elongated hole 33.
  • When the lens 13 thermally expands, the width of each elongated hole 33 also increases. The elongated holes 33 of the present embodiment each have the width increasing portion 33e, in which the width of the elongated hole 33 increases as the distance from the positioning point C increases. Therefore, when the lens 13 thermally expands and each insertion portion 14a moves in the corresponding elongated hole 33 so as to approach the first curved surface 331, the insertion portion 14a moves to a narrower portion in the elongated hole 33. Thus, even when the lens 13 thermally expands, the distance between the inner peripheral surface 330, which defines the elongated hole 33, and the insertion portion 14a of the fastener 14 is unlikely to increase. This suppresses the displacement of the lens 13 in the width direction of each elongated hole 33.
  • As shown in Fig. 8, when the temperature inside the case 15 decreases, the lens 13, which is made of plastic, thermally contracts. In contrast, the substrate 11 and the fastener 14, which are made of metal, thermally expand negligibly. In the present embodiment, the lens 13 includes the elongated holes 33, which extend in a radial pattern centered on the positioning point C. This structure allows the lens 13 to thermally contract in the extending direction of each elongated hole 33. The lens 13 moves relative to each fastener 14 so that the insertion portion 14a of the fastener 14 approaches the second curved surface 332 in the corresponding elongated hole 33.
  • When the lens 13 thermally contracts, the width of each elongated hole 33 also decreases. The elongated holes 33 of the present embodiment each have the width increasing portion 33e, in which the width of the elongated hole 33 increases as the distance from the positioning point C increases. Therefore, when the lens 13 thermally contracts and each insertion portion 14a moves in the corresponding elongated hole 33 so as to approach the second curved surface 332, the insertion portion 14a moves to a wider portion in the elongated hole 33. Thus, even when the lens 13 thermally contracts, the distance between the inner peripheral surface 330, which defines the elongated hole 33, and the insertion portion 14a of the fastener 14 is unlikely to decrease. As a result, the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a are less likely to interfere with each other. This suppresses the deformation of the lens 13 due to the hindrance of the contraction of the lens 13.
  • Since the displacement of the lens 13 and the deformation of the lens 13 are suppressed, the lens 13 is unlikely to be displaced in relation to the substrate 11. When the lens 13 is unlikely to be displaced in relation to the substrate 11, the lens 13 is also unlikely to be displaced in relation to the light sources 12 fixed to the substrate 11. Consequently, even if the lens 13 thermally expands or thermally contracts, the light source device 10 readily achieves the desired illuminance and the desired illumination range.
    • Advantages of the Present Embodiment
  • The present embodiment has the following advantages.
    1. (1) The light source device 10 includes the substrate 11, which is a metal fixing member or a base member, the light source 12 fixed to the substrate 11, and the plastic lens 13 fixed to the substrate 11 with the metal fasteners 14. The lens 13 includes the elongated holes 33, through which the fasteners 14 are inserted. The elongated holes 33 extend in a radial pattern centered on the specified positioning point C defined in the lens 13. Each of the elongated holes 33 includes a width increasing portion 33e, in which the width of the elongated hole 33 increases as the distance from the positioning point C increases.
      With this configuration, the elongated holes 33 extend in a radial pattern centered on the positioning point C. This structure allows the lens 13 to thermally expand and thermally contract in the extending direction of each elongated hole 33. Each of the elongated holes 33 includes a width increasing portion 33e, in which the width of the elongated hole 33 increases as the distance from the positioning point C increases. Therefore, even if the lens 13 thermally expands or thermally contracts, the distance between the inner peripheral surface 330, which defines the elongated hole 33, and the fastener 14 is unlikely to change. It is thus possible to suppress displacement of the lens 13 at the time of thermal expansion of the lens 13, and to suppress interference between the lens 13 and the fastener 14 at the time of thermal contraction of the lens 13.
    2. (2) At the position in each elongated hole 33 where the insertion portion 14a of the fastener 14 is located, the shortest distance D in each perpendicular direction between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a is greater than or equal to the minimum clearance obtained by subtracting the maximum allowable dimension defined for the second dimension from the minimum allowable dimension defined for the first dimension. With this configuration, a clearance is created between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a, taking into consideration dimensional errors of the elongated hole 33 and the insertion portion 14a. This allows for smooth movement of the insertion portion 14a in the elongated hole 33 due to thermal expansion or thermal contraction of the lens 13.
    3. (3) The shortest distance D in each perpendicular direction between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a remains the same regardless of whether the temperature inside the case 15 is at the reference temperature, the first temperature, or the second temperature. With this configuration, the shortest distance D in each perpendicular direction between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a is constant regardless of the temperature inside the case 15.
    4. (4) The inner peripheral surface 330, which defines the elongated hole 33, includes the first curved surface 331, the second curved surface 332, and the two flat surfaces 333. The first curved surface 331 forms a part of the outer peripheral surface of a first imaginary cylinder C1. The second curved surface 332 forms a part of the outer peripheral surface of the second imaginary cylinder C2, which has a larger diameter than the first imaginary cylinder C1. The two flat surfaces 333 form two common external tangents L that externally contact the first imaginary cylinder C1 and the second imaginary cylinder C2. This configuration facilitates the formation of the elongated holes 33.
    5. (5) The elongated holes 33 include the first elongated hole 33a and the second elongated hole 33b. The first elongated hole 33a and the second elongated hole 33b are located on the first imaginary straight line L1, which passes through the positioning point C. The positioning point C is located between the first elongated hole 33a and the second elongated hole 33b.
      This configuration allows for thermal expansion of the lens 13 in which a portion of the lens 13 away from the positioning point C toward the first elongated hole 33a and a portion of the lens 13 away from the positioning point C toward the second elongated hole 33b move away from each other in the extending direction of the first imaginary straight line L1. This configuration also allows for thermal contraction of the lens 13 in which a portion of the lens 13 away from the positioning point C toward the first elongated hole 33a and a portion of the lens 13 away from the positioning point C toward the second elongated hole 33b approach other in the extending direction of the first imaginary straight line L1. The configuration thus suppresses the displacement of the positioning point C in the extending direction of the first imaginary straight line L1.
    6. (6) The elongated holes 33 further include the third elongated hole 33c and the fourth elongated hole 33d. The third elongated hole 33c and the fourth elongated hole 33d are located on the second imaginary straight line L2, which passes through the positioning point C and intersects with the first imaginary straight line L1. The positioning point C is located between the third elongated hole 33c and the fourth elongated hole 33d.
  • This configuration allows for thermal expansion of the lens 13 in which a portion of the lens 13 away from the positioning point C toward the third elongated hole 33c and a portion of the lens 13 away from the positioning point C toward the fourth elongated hole 33d move away from each other in the extending direction of the second imaginary straight line L2. This configuration also allows for thermal contraction of the lens 13 in which a portion of the lens 13 away from the positioning point C toward the third elongated hole 33c and a portion of the lens 13 away from the positioning point C toward the fourth elongated hole 33d approach each other in the extending direction of the second imaginary straight line L2. The configuration thus suppresses the displacement of the positioning point C in the extending direction of the second imaginary straight line L2.
  • Movements in the extending direction of the first imaginary straight line L1 of the fasteners 14 inserted into the first elongated hole 33a and the second elongated hole 33b are restricted by the contact of the fasteners 14 inserted into the third elongated hole 33c and the fourth elongated hole 33d with the inner peripheral surfaces 330 that define the corresponding elongated holes 33. This restricts the displacement of the lens 13 in the extending direction of the first imaginary straight line L1.
  • Movements in the extending direction of the second imaginary straight line L2 of the fasteners 14 inserted into the third elongated hole 33c and the fourth elongated hole 33d are restricted by the contact of the fasteners 14 inserted into the first elongated hole 33a and the second elongated hole 33b with the inner peripheral surfaces 330 that define the corresponding elongated holes 33. This restricts the displacement of the lens 13 in the extending direction of the second imaginary straight line L2.
  • It is thus possible to suppress the displacement of the lens 13 due to movement of each fastener 14 in the corresponding elongated hole 33 in the extending direction of the elongated hole 33.
  • (7) Each fastener 14 includes the collar 42. The first end face of the collar 42 in the axial direction is substantially flush with the distal end face 34a of the bulging portion 34 of the lens 13. This limits deformation of the lens 13 when the bolts 41 are tightened.
  • (8) Each fastener 14 includes the washer 43. The outer diameter of the washer 43 is larger than the outer diameter of the head 41b of the bolt 41. The washer 43 is disposed between the head 41b of the bolt 41 and the surface including the first end face of the collar 42 in the axial direction and the distal end face 34a of the bulging portion 34. This configuration increases the pressing area of the bulging portion 34 by the fastener 14.
    • Modifications
  • The above-described embodiment may be changed as described below. The above-described embodiment and the following modifications can be combined as long as the combined modifications remain technically consistent with each other.
  • The fixing member or the base member is not limited to the substrate 11. The fixing member or the base member may be a metal component different from the substrate 11.
  • As an example, the fixing member or the base member may be a heat sink. As another example, if the case 15 is made of metal, the fixing member or the base member may be the case 15. When the fixing member or the base member is a metal member different from the substrate 11, the light source 12 is fixed to the fixing member or the base member via the substrate 11 by fixing the substrate 11, to which the light source 12 is fixed, to the fixing member or the base member. The fasteners for fixing the substrate 11, to which the light source 12 is fixed, to the fixing member or the base member may be the same as or different from the fasteners 14 for fixing the lens 13 to the fixing member or the base member. However, the substrate 11 and the light source 12 must be fixed so as not to be displaced in relation to the fixing member or the base member even when the temperature inside the case 15 changes.
  • The substrate 11 may include through-holes instead of the internal thread holes 11a. In this case, the lens 13 and the substrate 11 may be fastened to each other by screwing the bolts 41, which are inserted into the elongated holes 33 of the lens 13 and the through-holes of the substrate 11, into nuts.
  • The light sources 12 are not limited to LEDs. The light sources 12 may be other light sources such as halogen lamps.
  • The number of light sources 12 may be changed.
  • The fasteners 14 do not necessarily need to include the collars 42. When the first end face of the collar 42 in the axial direction is not disposed on substantially the same plane as the distal end face 34a of the bulging portion 34, the washer 43 preferably covers the entire distal end face 34a of the bulging portion 34 in the width direction of the elongated hole 33. In this case, when the bolt 41 is tightened, the washer 43 is unlikely to sink into the bulging portion 34.
  • The fasteners 14 do not necessarily need to include the washers 43.
  • Instead of the bolt 41, each fastener 14 may include a pin that protrudes from the fixing member and has an external thread on the outer peripheral surface thereof. The pin is inserted into each elongated hole 33 of the lens 13 and then screwed into the nut.
  • Each fastener 14 may include a rivet instead of the bolt 41.
  • The positioning point C is not limited to the center of the plate portion 30. The positioning point C may be set at any position on the lens 13.
  • For example, when it is preferable that the position of the center of a specific one of the protrusions 31 remains unchanged in relation to the substrate 11, the positioning point C is set at the center of that protrusion 31.
  • The shape of the substrate 11 is not limited to a rectangle. The substrate 11 may have, for example, a square shape or a circular shape.
  • The shape of the plate portion 30 of the lens 13 is not limited to a rectangle. The plate portion 30 may have, for example, a square shape or a circular shape.
  • The shape of the plate portion 30 may be different from the shape of the substrate 11. The size of the plate portion 30 may be different from the size of the substrate 11.
  • The number of the elongated holes 33 provided in the lens 13 is not limited to four. The number of elongated holes 33 provided in the lens 13 may be changed. At least one of the holes arranged around the positioning point C may be an elongated hole 33.
  • One of the first elongated hole 33a and the second elongated hole 33b may be replaced by a round hole.
  • One of the third elongated hole 33c and the fourth elongated hole 33d may be replaced by round hole.
  • In the above-described embodiment, the elongated holes 33 are provided at the respective corners of the plate portion 30, but the arrangement of the elongated holes 33 is not limited thereto. For example, the first imaginary straight line L1 may be an imaginary straight line that passes through the positioning point C and extends in the longitudinal direction of the plate portion 30. The second imaginary straight line L2 may be an imaginary straight line that passes through the positioning point C and extends in the transverse direction of the plate portion 30.
  • At the position in each elongated hole 33 where the insertion portion 14a is located, the shortest distance D in each perpendicular direction between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a may be less than the minimum clearance obtained by subtracting the maximum allowable dimension defined for the second dimension from the minimum allowable dimension defined for the first dimension. In other words, the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a may be in contact with each other.
  • The shortest distance D in each perpendicular direction between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a does not necessarily remain the same at the reference temperature, at the first temperature, and at the second temperature inside the case 15. In other words, the distance between the inner peripheral surface 330, which defines the elongated hole 33, and the outer peripheral surface 140 of the insertion portion 14a does not necessarily need to be constant regardless of the temperature of the lens 13.
  • The inner peripheral surface 330, which defines the elongated hole 33, does not necessarily need to include the first curved surface 331, the second curved surface 332, and the two flat surfaces 333. As long as the elongated hole 33 includes the width increasing portion 33e, the shape of the elongated hole 33 may be changed. The insertion portion 14a of each fastener 14 does not necessarily need to have a cylindrical shape. The shape of the insertion portion 14a may be changed according to the shape of the elongated hole 33. However, the elongated hole 33 and the insertion portion 14a are formed such that the insertion portion 14a does not interfere with the first curved surface 331 when the temperature inside the case 15 is the first temperature, and the insertion portion 14a does not interfere with the second curved surface 332 when the temperature inside the case 15 is the second temperature.
  • For example, as shown in Fig. 9, the elongated hole 33 may have a trapezoidal shape, and the insertion portion 14a may have a prismatic shape with a trapezoidal cross-section when cut in a plane perpendicular to the thickness direction of the lens 13. In this case, the first curved surface 331 and the second curved surface 332 are replaced by flat surfaces. The outer peripheral surface 140 of the insertion portion 14a has two facing surfaces 140a extending parallel to the two flat surfaces 333. This configuration increases the size of the surface of the outer peripheral surface 140 of the insertion portion 14a that is located at a position separated, in the perpendicular direction, by the shortest distances D from the inner peripheral surface 330, which defines the elongated hole 33.
  • For example, as shown in Fig. 10, the dimension of the elongated hole 33 in the extending direction may be longer than the dimension of the elongated hole 33 in the extending direction in the above-described embodiment, which is indicated by the broken lines in Fig. 10. Specifically, the two flat surfaces 333 may be extended toward the positioning point C, so that the first curved surface 331 is located closer to the positioning point C than the first curved surface 331 of the above-described embodiment. By extending the two flat surfaces 333 toward the edge of the lens 13, the second curved surface 332 may be located closer to the edge of the lens 13 than the second curved surface 332 of the above-described embodiment.
  • In this case, when the temperature inside the case 15 is the first temperature, the intersection between each perpendicular line T and the corresponding flat surface 333 is displaced from the connection point between the first curved surface 331 and the flat surface 333. When the temperature inside the case 15 is the second temperature, the intersection between each perpendicular line T and the corresponding flat surface 333 is displaced from the connection point between the second curved surface 332 and the flat surface 333.
  • In the above-described embodiment, a case is discussed in which the lens 13 expands or contracts due to temperature changes in the case 15. However, the lens 13 may expand or contract due to a factor other than temperature changes.
  • For example, the lens 13 made of an organic plastic such as silicone rubber may swell due to contact with a solvent or the like.
  • For example, the lens 13 may expand due to moisture absorption or water absorption.
  • For example, when the light source device 10 is used over an extended period, the lens 13 may contract due to age-related degradation, such as an increase in hardness or a decrease in weight.
  • This configuration also accommodates expansion or contraction of the lens 13 caused by factors other than temperature changes. In such cases, the elongated hole 33 is designed considering the expected states of the lens 13 during expansion and contraction.
  • Various changes in form and details may be made to the examples above without departing from the spirit and scope of the claims and their equivalents. The examples are for the sake of description only, and not for purposes of limitation. Descriptions of features in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results may be achieved if sequences are performed in a different order, and/or if components in a described system, architecture, device, or circuit are combined differently, and/or replaced or supplemented by other components or their equivalents. The scope of the disclosure is not defined by the detailed description, but by the claims and their equivalents. All variations within the scope of the claims and their equivalents are included in the disclosure.

Claims (7)

  1. A light source device (10), comprising:
    a metal fixing member (11);
    a light source (12) fixed to the fixing member (11); and
    a plastic lens (13) fixed to the fixing member (11) with a metal fastener (14), wherein
    the lens (13) is provided with an elongated hole through (33) which the fastener (14) is inserted,
    the elongated hole (33) extends in a radial pattern centered on a specified positioning point (C) defined in the lens (13), and
    the elongated hole (33) includes a width increasing portion (33e) in which a width of the elongated hole (33) increases as a distance from the positioning point (C) increases.
  2. The light source device (10) according to claim 1, wherein
    the fastener (14) includes an insertion portion (14a) located in the elongated hole (33),
    an inner peripheral surface (330) defining the elongated hole (33) includes a surface defining the width increasing portion (33e),
    a direction along a perpendicular line (T) extending from a center (O) of the insertion portion (14a) toward the surface defining the width increasing portion (33e) is a perpendicular direction,
    a minimum allowable dimension is defined for a dimension in the perpendicular direction from the center (O) of the insertion portion (14a) to the inner peripheral surface (330) defining the elongated hole (33),
    a maximum allowable dimension is defined for a dimension in the perpendicular direction from the center (O) of the insertion portion (14a) to an outer peripheral surface (140) of the insertion portion (14a), and
    at a position where the insertion portion (14a) is located in the elongated hole (33), a shortest distance (D) in the perpendicular direction between the inner peripheral surface (330) defining the elongated hole (33) and the outer peripheral surface (140) of the insertion portion (14a) is greater than or equal to a minimum clearance obtained by subtracting the maximum allowable dimension from the minimum allowable dimension.
  3. The light source device (10) according to claim 1, further comprising a case (15) that accommodates the fixing member (11), the light source (12), and the lens (13), wherein
    the fastener (14) includes an insertion portion (14a) located in the elongated hole (33),
    an inner peripheral surface (330) defining the elongated hole (33) includes a surface defining the width increasing portion (33e),
    a direction along a perpendicular line (T) extending from a center (O) of the insertion portion (14a) toward the surface defining the width increasing portion (33e) is a perpendicular direction,
    a temperature inside the case (15) when the light source device (10) is used in a normal-temperature environment is defined as a reference temperature,
    a temperature inside the case (15) when the light source device (10) is used at a highest temperature in an intended operating temperature range of the light source device (10) is defined as a first temperature,
    a temperature inside the case (15) when the light source device (10) is used at a lowest temperature in the intended operating temperature range of the light source device (15) is defined as a second temperature, and
    a shortest distance (D) in the perpendicular direction between the inner peripheral surface (330) defining the elongated hole (33) and an outer peripheral surface (140) of the insertion portion (14a) remains the same regardless of whether the temperature inside the case (15) is at the reference temperature, the first temperature, or the second temperature.
  4. The light source device (10) according to claim 2, further comprising a case (15) that accommodates the fixing member (11), the light source (12), and the lens (13), wherein
    a temperature inside the case (15) when the light source device (10) is used in a normal-temperature environment is defined as a reference temperature,
    a temperature inside the case (15) when the light source device (10) is used at a highest temperature in an intended operating temperature range of the light source device (10) is defined as a first temperature,
    a temperature inside the case (15) when the light source device (10) is used at a lowest temperature in the intended operating temperature range of the light source device (10) is defined as a second temperature, and
    a shortest distance (D) in the perpendicular direction between the inner peripheral surface (330) defining the elongated hole (33) and the outer peripheral surface (140) of the insertion portion (14a) remains the same regardless of whether the temperature inside the case (15) is at the reference temperature, the first temperature, or the second temperature.
  5. The light source device (10) according to any one of claims 1 to 4,
    wherein an inner peripheral surface (330) defining the elongated hole (33) includes:
    a first curved surface (331) forming a part of an outer peripheral surface of a first imaginary cylinder (C1);
    a second curved surface (332) forming a part of an outer peripheral surface of a second imaginary cylinder (C2), the second imaginary cylinder (C2) having a diameter larger than that of the first imaginary cylinder (C1); and
    two flat surfaces (333) forming two common external tangents (L) that externally contact the first imaginary cylinder (C1) and the second imaginary cylinder (C2).
  6. The light source device (10) according to any one of claims 1 to 5, wherein
    the elongated hole (33) is one of multiple elongated holes (33) including a first elongated hole (33a) and a second elongated hole (33b),
    the first elongated hole (33a) and the second elongated hole (33b) are located on a first imaginary straight line (L1) passing through the positioning point (C), and
    the positioning point (C) is located between the first elongated hole (33a) and the second elongated hole (33b).
  7. The light source device (10) according to claim 6, wherein
    the elongated holes (33) further include a third elongated hole (33c) and a fourth elongated hole (33d),
    the third elongated hole (33c) and the fourth elongated hole (33d) are located on a second imaginary straight line (L2) that passes through the positioning point (C) and intersects with the first imaginary straight line (L1), and
    the positioning point (C) is located between the third elongated hole (33c) and the fourth elongated hole (33d).
EP25151926.0A 2024-01-17 2025-01-15 Light source device Pending EP4589194A1 (en)

Applications Claiming Priority (1)

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JP2024005317A JP2025111121A (en) 2024-01-17 2024-01-17 light source device

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EP4589194A1 true EP4589194A1 (en) 2025-07-23

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EP (1) EP4589194A1 (en)
JP (1) JP2025111121A (en)
CN (1) CN120332717A (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014165273A (en) * 2013-02-22 2014-09-08 Panasonic Corp Led module and lighting equipment
US20190178461A1 (en) * 2017-12-07 2019-06-13 Koito Manufacturing Co., Ltd. Light source unit and fixing method of lens thereof
US11333328B1 (en) * 2021-04-01 2022-05-17 Smart Electric Works Co., Ltd. Lampshade module capable of replacing optical projection elements

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014165273A (en) * 2013-02-22 2014-09-08 Panasonic Corp Led module and lighting equipment
US20190178461A1 (en) * 2017-12-07 2019-06-13 Koito Manufacturing Co., Ltd. Light source unit and fixing method of lens thereof
JP2019102389A (en) 2017-12-07 2019-06-24 株式会社小糸製作所 Light source unit and lens fixing method of light source unit
US11333328B1 (en) * 2021-04-01 2022-05-17 Smart Electric Works Co., Ltd. Lampshade module capable of replacing optical projection elements

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CN120332717A (en) 2025-07-18

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