JP6479442B2 - Helmet shades and helmets - Google Patents

Description

  The present invention relates to a helmet shade and a helmet.

  Helmets are generally known as “protective caps for protecting the head from impacts, etc.”, and there are various types of items widely (Patent Document 1, etc.).

  A helmet for passengers of various vehicles such as motorcycles is provided with a shade (also referred to as “visor”, “shield plate”, etc.) for protecting the face against rain and wind.

  In addition, a helmet used by an operator who performs “work involving danger” is often provided with a shade for face protection. Conventionally, these helmets have been subjected to "various devices for good face protection".

  In general, many shades such as those described above have a shape in which a parallel plate-like transparent plate such as glass or resin is smoothly bent so as to be concave on the face side of the helmet wearer.

  A shade formed by bending a parallel plate-like transparent plate has a lens action (also referred to as a lens effect) due to “curvature generated on the outer surface and the inner surface”.

  The shade generally has “different curvatures” in the vertical direction and the horizontal direction when the helmet is worn, and the lens action is different in both directions.

  Specifically, the refractive power differs between the vertical direction and the horizontal direction of the shade. In general, the refractive power in the left-right direction is larger than the refractive power in the vertical direction.

  The difference in refractive power between the vertical direction and the horizontal direction causes a so-called “astigmatic difference”. If there is such an astigmatic difference, the focus position will be different vertically and horizontally, so the `` front object seen through the shade '' will dissociate vertically and horizontally like astigmatism, giving the helmet wearer a sense of incongruity .

  In particular, when the line of sight is moved, the “appearance of the object” fluctuates, and this discomfort becomes noticeable.

  “Fluctuations in the appearance of objects seen through the shade” can be a threat to the safety of passengers when the vehicle is at high speed, and can be a hindrance to workers who perform dangerous tasks. .

  Conventionally, the problem of the lens action of the shade provided in the helmet is not known as far as the inventors know.

  This invention makes it a subject to implement | achieve the novel shade for helmets which reduced or removed the said lens effect | action.

The helmet shade according to the present invention is a helmet shade disposed at the front portion of the helmet body, and both the outer surface and the inner surface are configured by a transparent plate that is a concave curved surface toward the inside of the helmet body. The concave curved surface forming the outer side surface and the inner side surface is left-right symmetric in the left-right direction, the left-right symmetric symmetry plane is parallel to the vertical cross-section, the horizontal direction is perpendicular to the vertical cross-section including the optical axis. when the cross section, in the effective visual field, the longitudinal section and astigmatic difference of the transverse cross-section 0.06 m ^-1 Ri der below, at least one of the inner and outer surfaces of the effective visual field, the helmet Ru toroidal surface der concave towards the inside of the body.

According to the present invention, a novel helmet shade can be realized in which the astigmatic difference between the longitudinal section and the lateral section is as small as 0.06 m ⁻¹ or less.

It is a perspective view which shows one example of a helmet. It is a perspective view which shows the shade with which the helmet of FIG. 1 was mounted | worn. It is a figure for demonstrating the effective visual field area | region of the shade for helmets.

  FIG. 1 shows a perspective view of an example of a “helmet”. In FIG. 1, reference numeral 1 denotes a helmet, reference numeral 10 denotes a helmet shade, and reference numeral 20 denotes a helmet body.

  Hereinafter, the helmet shade is simply referred to as a shade.

  The helmet 1 is “for motorcycles”.

  As shown in FIG. 1, the shade 10 is disposed on the front portion of the helmet body 20.

  FIG. 2 is a perspective view showing the appearance of the shade 10 attached to the helmet body 20 of the helmet 1 shown in FIG.

  The shade 10 shown in FIG. 2 is formed of a “transparent plate” such as glass or resin.

  As shown, x, y and z directions are defined.

  In the state where the shade 10 is arranged on the helmet body 20, the right side of the shade 10 (corresponding to the positive side in the z direction) is “inside the helmet body 20” in FIG.

  Hereinafter, in the state where the shade 10 is arranged on the helmet body, the front side of the helmet body (corresponding to the negative side in the z direction) is referred to as “face side”. That is, when the helmet 1 of FIG. 1 is worn on the head, the face of the wearer faces the “face side”.

  That is, as shown in FIG. 1, the shade 10 is disposed in the “front portion” of the helmet body 20, that is, “the portion on the front side of the wearer's face”.

  The left-right direction (corresponding to the direction of the y-axis) of the shade 10 facing the wearer's face when the helmet 1 is worn is referred to as the “lateral direction of the shade 10”. The vertical direction (corresponding to the direction of the X axis) when viewed from the wearer's face side is referred to as the “longitudinal direction of the shade 10”.

  Of the two surfaces of the shade 10, the surface facing the inside of the helmet body is referred to as an “inner surface”, and the surface facing the outside is referred to as an “outer surface”. That is, the inner surface is the “side facing the wearer's face”.

  As shown in FIG. 2, the shade 10 is formed of “a concave surface on the face side”, that is, “a transparent plate having a concave surface on the inside of the helmet body”.

  The concave curved surface forming the outer surface side and the inner surface side of the shade 10 is “left-right symmetric” in the left-right direction (the “lateral direction”), and the left-right symmetric symmetry surface is referred to as “longitudinal section”.

  A plane parallel to the left-right direction and including the optical axis and perpendicular to the longitudinal section is referred to as a “lateral section”. The “optical axis” is “an axis perpendicular to the concave curved surface in the longitudinal section”.

  In other words, the line of intersection between the longitudinal section and the lateral section forms the “optical axis”.

  As shown in FIG. 2, the shade 10 includes attachment / detachment portions 11 and 12 at both end portions in the left-right direction (referred to as “outside the viewing angle region” and “outside the viewing angle region”). 11 and 12 can be attached / detached to / from the helmet body 20 by attaching / detaching them to / from the helmet body 20 side.

  Further, in a state where the shade 10 is mounted on the helmet body 20, the shade 10 can be opened and closed with respect to the helmet body 20 by swinging with the attaching / detaching portions 11 and 12 of the shade 10 as the swing base point.

  When the shade 10 is opened with respect to the helmet body 20, a part of the face of the wearer in the helmet 1 is exposed.

  In other words, “from the middle of the face to the lower part of the mouth” is released.

  The “head portion at the upper part of the forehead” is protected by the helmet body portion above the shade 10, and the “chin portion below the mouth” is protected by the helmet body portion below the shade 10.

  As described above, the shade 10 is “transparent”, but it is not necessarily “colorless and transparent”. As long as the front can be clearly seen through the shade 10, the shade 10 is colored in an appropriate color. It may be.

  The “appropriate color” is, for example, yellow, gold, silver, blue, green, etc., and can also be “a color that changes according to light from the outside world”.

  The shade of the present invention is characterized by the following points.

That is, der 0.06 m ^-1 or less in absolute value, "longitudinal section and transverse section astigmatism with" is, at least one of "helmet body of the inner surface and the outer surface in the effective viewing area in the effective visual field The toroidal surface is concave toward the inside.

  The “effective visual field region” is a region in front of the eyes in the “entire visual field through the shade” of the wearer wearing the helmet, and “a region where an observation target can be satisfactorily observed when performing driving or work”.

  The effective visual field area is not “determined uniformly” but can be determined as a design matter for each helmet in which the shade is disposed.

  In the examples described later, a typical example of the effective visual field region is shown.

  The “astigmatic difference” is a difference between “refractive power in the longitudinal section” and “refractive power in the lateral section” due to the lens action of the shade, and its unit is “diopter”.

  “Diopter” is “1 / f” when the focal length f is expressed in “m units”.

  The focal length by the lens action of the shade of the present invention is “fx (m)” for the longitudinal section and “fy (m)” for the lateral direction.

At this time, “refractive power in the longitudinal section: Dx” expressed in diopter units (m ⁻¹ ) is “1 / fx”, and “refractive power in the lateral section: Dy” is “1 / fy”. .

  In this specification, “astigmatic difference” is defined by a relative value of “Dx−Dy”.

Therefore, the shade of the present invention has a condition that “the astigmatic difference is 0.06 m ⁻¹ or less”, that is, “Dx−Dy” is as follows:
−0.06 m ⁻¹ ≦ Dx−Dy ≦ + 0.06 m ⁻¹
Satisfied. Hereinafter, this condition is referred to as “condition A”.

  If the astigmatic difference in units of diopters satisfies the condition A, the difference between the vertical object and the horizontal object of the “front object viewed through the shade” will be sufficiently small so that there is no sense of incongruity, and the object appears when the line of sight is moved. Fluctuations in the direction are hardly noticeable.

  Therefore, when the helmet wearer is a vehicle occupant, safety is increased, and when the helmet wearer is a worker who performs a dangerous work, the hindrance to work due to astigmatism is effectively reduced.

  Satisfying the condition A assumes that the shade portion constituting the effective visual field region portion is a “lens” and follows the aberration correction method (method for correcting astigmatism), the surface shape of the outer surface and the inner surface, It can be realized by adjusting the thickness distribution in the shade.

The above-mentioned refractive powers: Dx and Dy are arbitrary as long as the astigmatic difference as a relative value satisfies the condition A. However, practically, these values are each 0.12 m ^{−1 in} absolute value. The following is preferable.

  The surface shape of the outer side surface and the inner side surface of the effective visual field region portion of the shade of the present invention can be various surface shapes.

However, at least one of the inner surface and the outer surface in the effective visual field region is a “toroidal surface that is concave toward the inside of the helmet body” .

  In this case, one of the inner surface and the outer surface can be a “concave toroidal surface” when viewed from the face side, and the other can be a free-form surface.

  In this case, it is preferable that the concave toroidal surface of the concave toroidal surface and the free-form surface viewed from the face side is the inner surface.

  As described above, the shade of the present invention satisfies the above-mentioned “condition A” in the effective visual field region. In this case, it goes without saying that “the astigmatic difference is set to 0” is included.

  Of course, even if the astigmatic difference is set to 0, it is not limited to exactly 0, but may be substantially 0 (for example, “0.0000 or less”).

  When the astigmatic difference is set to 0, one of the refractive power (Dx) in the longitudinal section and the refractive power (Dy) in the transverse section in the effective visual field region is matched with the other to “set the astigmatic difference to 0”. Can do.

  That is, the refractive power of the longitudinal section: Dx can be adjusted by correcting the refractive power of the transverse section: Dy, and the astigmatic difference can be made zero. : By adjusting Dy by correction and adjusting it to the refractive power Dx of the longitudinal section, the astigmatic difference can be made zero.

In addition, the shade thickness T in the effective visual field region is equal to the thickness on the optical axis T0.
(1) 0.3T0 ≦ T ≦ 2T0
Is preferably satisfied.

  If the upper limit of condition (1) is exceeded, part of the shade will become thick, and the shade will be “heavy”. Especially when the shade is formed of tempered glass or the like, the weight will tend to increase, and the weight of the helmet itself will also be increased. It tends to be heavy.

  If the lower limit of the condition (1) is exceeded, the shade may become too thin in part, and the required strength may not be obtained from the viewpoint of safety.

In the effective field of view, the curvature radius of the outer surface in the longitudinal section: Rx1, the curvature radius of the inner surface: Rx2, the curvature radius of the outer surface in the transverse section: Ry1, and the curvature radius of the inner surface: Ry2 are:
(2) 200 <Rx1 <1000, 200 <Rx2 <1000
(3) 70 <Ry1 <400, 70 <Ry2 <400
Is preferably satisfied.

  Assuming a practical shade, each of the above curvature radii is preferably in a range that satisfies the conditions (2) and (3). By combining these radii of curvature, the astigmatism is reduced together with the lens action (refractive power). It can be corrected well.

  Prior to giving a specific example, the form of the shade will be described with reference to FIG.

  In addition, since it seems that there is no possibility of confusion, the reference numeral 10 is applied to the shade as in FIGS.

  The “y direction” shown in FIG. 3A is a direction orthogonal to the drawing of FIG. 3A, and is the “lateral direction (left-right direction)” in the above description.

  The “x direction” is the “vertical direction (vertical direction)” in the above description.

The xz plane is a plane parallel to the “longitudinal section”.
The shade 10 in FIG. 3A has a “cross-sectional shape in a longitudinal section”. That is, as described above, the shade 10 has a symmetric shape in the y direction of the figure, with the cross section giving the shape of FIG.

  In FIG. 3A, reference numeral 10A indicates the “outer surface” of the shade 10, and reference numeral 10B indicates the “inner surface”.

  As described above, the outer side surface 10A and the inner side surface 10B may be “toroidal surfaces” or “free curved surfaces”. Therefore, the shape of the outer side surface 10A and the inner side surface 10B appearing in FIG. 3A can be “arc shape” or “non-arc shape”.

  The radius of curvature of the outer surface 10A in the longitudinal cross section shown in FIG. 3A is “Rx1”, and the radius of curvature of the inner surface 10B is “Rx2”.

  These curvature radii are “paraxial curvature radii” in the vicinity of the optical axis when the outer surface and the inner surface are free-form surfaces and the outer surface 10A and the inner surface 10B in FIG. Say it.

  This “optical axis” is indicated by reference numeral AX in FIG.

  The outer peripheral surfaces 10A and 10B in the longitudinal section are each “part of a curved surface including a broken line”, and the “shape in the longitudinal section” of the curved surface is vertically symmetrical with respect to the optical axis AX.

  The thickness of the shade 10 on the optical axis AX is “T”.

  The part indicated by “ξ” in FIG. 3A is a “vertical effective visual field” when the wearer's eye E sees the outside through the shade 10, and this is referred to as a “vertical effective visual field region”. Call.

  “Α” is the vertical distance between the line of sight when the wearer's eye E looks straight ahead (the negative side in the z direction) and the “upper end of the effective vertical field of view”.

  In FIG. 3A, the upper end of the effective field area in the vertical direction coincides with the optical axis AX, but this is only an example, and the present invention is not limited to this.

  The z direction and the optical axis AX are allowed to be “about ± 15 degrees parallel”.

  In FIG. 3A, the symbol PA is the center of curvature of the outer surface 10A in the longitudinal section, the symbol PB is the center of curvature of the inner surface 10B in the section, and the angle θ is in the section. This is the angle from which the vertical effective visual field region ξ is viewed from the center of curvature P1.

  In addition, “T2” indicates the thickness of the shade 10 at the lower end portion of the vertical effective visual field region ξ in the vertical cross section.

  FIG. 3B shows a cross-sectional shape of the shade 10 cut along a horizontal plane (transverse cross section) including the optical axis AX.

  Since the shade 10 is symmetric with respect to the “longitudinal section” in the lateral direction (y direction) as described above, the shape in the lateral section shown in FIG. 3B is also symmetric with respect to the optical axis AX in the y direction. Is.

  The outer side surface 10A and the inner side surface 10B can be “toroidal surfaces” or “free curved surfaces” as described above, and the shapes of the outer side surface 10A and the inner side surface 10B appearing in FIG. It may be “non-arc shaped”.

  Here, the radius of curvature of the outer surface 10A in the transverse cross section shown in FIG. 3B is “Ry1”, and the radius of curvature of the inner surface 10B is “Ry2”.

  These curvature radii are “paraxial curvature radii” in the vicinity of the optical axis when the outer surface and the inner surface are free-form surfaces and the outer surface 10A and the inner surface 10B in FIG. Say it.

  Curvature radius: Ry1 is the distance on the optical axis AX of the outer surface 10A and the center of curvature QA of the outer surface 10A in the in-plane (lateral cross section) of FIG.

  Similarly, the radius of curvature: Ry2 is the distance on the optical axis AX between the center of curvature QB of the outer surface 10B and the inner surface 10B in the transverse cross section.

  The part indicated by “η” in FIG. 3B is an “horizontal (horizontal) effective visual field” in which the wearer's right eye ER and left eye EL see the outside through the shade 10, It is referred to as a “direction effective viewing area”.

  Also, “βR” is the distance between the line of sight when the right eye ER looks straight ahead at infinity and “a plane that includes the optical axis AX and is parallel to the vertical direction (longitudinal section)”, and “βL” is the left eye EL The distance between the line of sight and the longitudinal section when looking straight ahead at infinity, they are equal to each other (βR = βL).

  Also, the length LT shown in FIG. 3B represents “the size of the shade 10 in the horizontal direction (left-right direction)”.

  It is assumed that the shade 10 shown in FIG. 3 is manufactured by “molding with a mold”. In FIG. 3 (b), the portion that forms an angle: γ with respect to the direction orthogonal to the optical axis AX is “positions for type matching (this is at both ends in the y direction)”. The thickness of the shade at the position is “T1”.

  The “effective visual field area” is an area area on the shade determined by the vertical effective visual field area ξ and the horizontal effective visual field area η described above, and the shade 10 is viewed from the negative side in the z direction. In the state, the region is a “rectangular shape having two sides of ξ and η”.

  In addition, an angle δ shown in FIG. 3B is an angle from the optical axis AX that expects an intersection of the “line of sight straight ahead” from the right eye ER and the inner surface 10B.

  An angle: ε is an angle formed by a line extending from the center of curvature QB of the inner side surface 10B to one end of the horizontal effective visual field region η in the horizontal cross section and the vertical cross section.

  The angle δ is determined by the positional relationship between the wearer's eyes (ER, EL) and the shade 10, and the lateral effective visual field region η is determined according to the positional relationship determined in this way.

  Hereinafter, comparative examples and examples will be described.

  The comparative examples and examples described below are based on the shade 10 described with reference to FIG.

That is, the effective visual field area in the vertical direction: ξ = 150 mm, the size in the left-right direction: LT = 204 mm
, Lateral effective visual field area: η = 125 mm, distance: βR = βL = 32 mm.

  Further, the distance: α = 70 mm, the angle: θ = 22.02 degrees, the angle: δ = 18.66 degrees, the angle: ε = 37.33 degrees (= 2δ), and the angle: γ = 10 degrees.

  The material of the shade 10 is assumed to be “resin having a refractive index of 1.585 and an Abbe number of 29.9”. The shade 10 is produced by “molding” using this resin.

  In the following examples, the unit of the quantity having a length dimension is “mm” unless otherwise specified.

"Comparative example"
First, data of a comparative example is shown.
The comparative example is an example in which the resin plate having a thickness of 2 mm is bent to form a shade.

  The data of the comparative example is shown in Table 1.

  In Table 1, “surface” in the left column indicates an outer surface and an inner surface, “1” indicates an outer surface, and “2” indicates an “inner surface”.

  Further, light is incident from the outer surface and emitted from the inner surface, and therefore, the direction from the outer surface to the inner surface (z direction in FIG. 3) is “positive”.

  Rx and Ry are the radii of curvature in the above-described longitudinal section and the transverse section. The surface 1 is “Rx1, Ry1” and the surface 2 is “Rx2, Ry2.” “T” is the thickness on the optical axis, “Nd” is the refractive index of the material (= 1.585), and “νd” is the Abbe number (= 29.9).

“Aspherical coefficient” means that an aspherical shape is obtained by using a reciprocal of a paraxial radius of curvature (paraxial curvature): C, a height from an optical axis AX: H, and a conic constant: K.
Z = CH ² / [1 + √ {1- (1 + K) C ² H ² }]
This corresponds to the conic constant: K.

  H is the “distance between the optical axis and the non-arc shape” in the x direction when the non-arc shape is a shape in the longitudinal section, and when the non-arc shape is a shape in the transverse section, It is the distance between the “optical axis and non-arc shape” in the y direction. The same applies to the following.

  The above-mentioned “Rx: Crx” is a non-arc-shaped conical constant in the longitudinal section, and “Ry: Cry” is a non-arc-shaped conical constant in the transverse section.

  The shade of the comparative example is a toroidal surface that is concave on the face side on both the outer side surface and the inner side surface, and does not use an aspherical surface, so both aspherical coefficients: Crx and Cry are zero.

  Other data in the comparative example is shown in Table 2.

  In Table 2, T1 and T2 are shade thicknesses described with reference to FIG.

  The “thickness difference” is a value of the difference between the thicknesses: T1, T2, and T: T1-T2, T-T1, and T-T2 that has the maximum absolute value.

  In the comparative example, since a resin plate having a thickness of 2 mm is bent to form a shade, the thickness of the shade is 2 mm everywhere and “thickness difference = 0”.

  In the “astigmatic difference” column, “Dx” is “refractive power in the longitudinal section”, “Dy” is “refractive power in the transverse section”, and the unit is “diopter”.

  In the shade of the comparative example, the curvature radius of the outer surface is larger than that of the inner surface in both the longitudinal section and the lateral section. For this reason, the refractive power is “negative” both in the longitudinal section and in the lateral section.

The relative value of “difference (Dx−Dy)” is the value of “astigmatic difference” (in diopter units).
In the comparative example, this value is larger than 0.06.

  The “meaning of the notation” in each table described above with reference to Tables 1 and 2 is the same in the following examples.

  Hereinafter, 13 examples of the shade according to the present invention will be described.

"Example 1"
The data of Example 1 is shown in Table 3 following Table 1.

  Other data of Example 1 is shown in Table 4 following Table 2.

  In Example 1, the astigmatic difference values are smaller than 0.0480 and 0.06, and the astigmatic difference is improved as compared with the comparative example.

"Example 2"
The data of Example 2 is shown in Table 5 following Table 1.

  Other data of Example 2 is shown in Table 6 following Table 2.

  In Example 2, the astigmatic difference is as extremely small as 0.008. However, the thickness D on the optical axis is slightly large at 5 mm.

"Example 3"
The data of Example 3 is shown in Table 7 following Table 1.

  Other data of Example 3 is shown in Table 8 following Table 2.

  In Example 3, the thickness of the shade on the optical axis is as thin as 2 mm, and the difference in thickness is as small as 1.02 in absolute value.

  In the shade of Example 3, the radius of curvature of the outer side surface of the shade is larger in the inner side surface than the outer side surface in both the longitudinal section and the transverse section, and has a positive refractive power as a lens action.

  Accordingly, the refractive powers: Dx and Dy are both positive.

  The astigmatic difference is 0.0001, which is even smaller than that of Example 2.

Example 4
The data of Example 4 is shown in Table 9 following Table 1.

  Other data of Example 4 is shown in Table 10 following Table 2.

  The shade of Example 4 also has a positive refractive power as a lens action.

Accordingly, the refractive powers: Dx and Dy are both positive.
The thickness of the shade on the optical axis is as thin as 2 mm, and the difference in thickness is as small as 1.05 in absolute value. The astigmatic difference is 0.0001, which is even smaller than that of Example 2.

"Example 5"
The data of Example 5 is shown in Table 11 following Table 1.

  Other data of Example 5 is shown in Table 12 following Table 2.

  The shade of Example 5 also has a positive refractive power as a lens action.

  Accordingly, the refractive powers: Dx and Dy are both positive. The thickness of the shade on the optical axis is as thin as 3 mm, and the thickness difference is as small as 1.58 in absolute value.

  The astigmatic difference (= | −0.0001 |) is 0.0001, which is even smaller than that of Example 2.

"Example 6"
The data of Example 6 is shown in Table 13 following Table 1.

  Other data of Example 6 is shown in Table 14 following Table 2.

  Also in the shade of Example 6, the shade has a negative refractive power as a lens action.

  Accordingly, both refractive powers Dx and Dy are negative. The thickness on the optical axis of the shade is as thin as 2 mm, and the difference in thickness is as small as 1.34 in absolute value.

  The astigmatic difference is as small as 0.0000 and is “substantially 0”.

  The “shape in the transverse cross section” of the shade of Example 6 is the same as that of the comparative example.

  Therefore, the value of “Dy” is the same value (−0.0727) as the shade of the comparative example.

  In Example 6, the radius of curvature Rx in the longitudinal cross section on the outer surface (surface 1): Rx is different from that in the comparative example, a large Dx is intentionally generated, and this Dx is matched with Dy. The point difference is substantially “0”.

"Example 7"
The data of Example 7 is shown in Table 15 following Table 1.

  Other data of Example 7 is shown in Table 16 following Table 2.

  The shade of Example 7 also has a negative refractive power as a lens action.

  Accordingly, both refractive powers Dx and Dy are negative. Thickness on the optical axis of the shade: D is as thin as 2 mm, and the difference in thickness is as small as 1.34 in absolute value.

  The astigmatic difference is as small as 0.0000 and is substantially zero.

  The “shape in the transverse cross section” of the shade of Example 7 is the same as that of the comparative example.

  Therefore, the value of “Dy” is the same value (−0.0727) as that of the shade of the comparative example.

  In Example 7, the curvature radius Rx in the longitudinal cross section on the inner side surface (surface 2): Rx is different from that of the comparative example, a large Dx is intentionally generated, and this Dx is matched with Dy. The point difference is substantially “0”.

"Example 8"
The data of Example 8 is shown in Table 17 following Table 1.

  Other data of Example 8 is shown in Table 18 following Table 2.

  The shade of Example 8 also has a negative refractive power as a lens action.

  Accordingly, both refractive powers Dx and Dy are negative. The thickness on the optical axis of the shade is as thin as 2 mm, and the difference in thickness is as small as 0.00 in absolute value.

  The amount of astigmatic difference is as small as 0.0000 and is substantially zero.

The “shape in the longitudinal section” of the shade of Example 8 is the same as that of the comparative example.
Therefore, the value of “Dx” is the same value (−0.0046) as the shade of the comparative example.

  In Example 8, the curvature radius: Ry in the transverse cross section on the outer surface (surface 1) is made different from that of the comparative example to generate “Dy that matches Dx”, and the astigmatic difference is substantially “0”. It is said.

"Example 9"
The data of Example 9 is shown in Table 19 following Table 1.

  Other data of Example 9 is shown in Table 20 according to Table 2.

  The shade of Example 9 also has negative refractive power as a lens action.

  Therefore, both Dx and Dy in the astigmatic difference are negative. The thickness of the shade on the optical axis is as thin as 2 mm, and the difference in thickness is as small as 0.98 in absolute value.

  The amount of astigmatic difference is as small as 0.0000 and is substantially zero.

  The shape in the longitudinal section of the shade of Example 9 is the same as that of the comparative example, and therefore the value of “Dx” is the same value (−0.0046) as that of the shade of the comparative example.

  In Example 9, the curvature radius: Ry in the transverse cross section on the inner side surface (plane 2) is made different from that of the comparative example to generate “Dy matching Dx”, and the astigmatic difference is substantially “0”. "

  The “surface shape of the outer and inner surfaces” of the shades of Examples 1 to 9 described above are all “toroidal surfaces” that are concave on the face side.

  As described above, the shape of the outer surface and the inner surface of the shade according to the present invention is not limited to the toroidal surface, and a free curved surface shape is also possible.

  Hereinafter, four examples using free-form surfaces will be described as Examples 10 to 13.

"Example 10"
The data of Example 10 is shown in Table 21 following Table 1.

  Other data of Example 10 is shown in Table 22 following Table 2.

  The tenth embodiment is an example in which the outer surface of the shade according to the sixth embodiment is used as a free curved surface.

  The shade of Example 10 has a negative refracting power as a lens action like the shade of Example 6, and refractive powers: Dx and Dy are both negative and small in absolute value of 0.0727. The thickness of the shade on the optical axis is as thin as 2 mm.

  The amount of astigmatic difference is as small as 0.0000 and is substantially zero.

  Also in the tenth embodiment, the astigmatic difference is substantially set to “0” by matching the value of the refractive power Dx in the longitudinal section with the refractive power Dy (−0.0727) in the transverse section. Yes.

The free-form surface shape of the outer surface is a non-arc shape in the longitudinal section, the above-mentioned formula:
Z = CH ² / [1 + √ {1- (1 + K) C ² H ² }]
The aspherical shape given as the aspherical coefficient corresponding to the conic constant: K: Crx as “1.346” is represented by “the center of curvature on the optical axis AX of the outer surface in the longitudinal section (FIG. 3). It is a surface shape obtained by rotating around an axis parallel to the x direction through (PA point of (a)).

  Thus, by making the outer surface into a free-form surface, the difference between the thickness on the optical axis: T and the thickness: T1, T2 can be reduced to an absolute value of 0.35.

  The thickness T2 in Table 20 is the maximum thickness in the longitudinal section in Example 10, and is a value at a position of 110 mm downward from the optical axis AX.

  The thickness at a position of 150 mm downward from the optical axis is 2 mm.

  The “shape in the transverse cross section” of the shade of Example 10 is the same as that of the comparative example, and thus the value of “Dy” is the same value as that of the shade of the comparative example.

"Example 11"
The data of Example 11 is shown in Table 23 following Table 1.

  Other data of Example 11 is shown in Table 24 according to Table 2.

  The eleventh embodiment is an example in which the inner surface of the shade according to the seventh embodiment is used as a free curved surface.

  The shade of Example 11 has a negative refracting power as a lens action like the shade of Example 7, and refractive powers: Dx and Dy are both negative and small in absolute value of 0.0727. The thickness of the shade on the optical axis is as thin as 2 mm.

  The amount of astigmatic difference is as small as 0.0000 and is substantially zero.

  Also in Example 11, the astigmatic difference is substantially set to “0” by matching the value of the refractive power Dx in the longitudinal section with the value of the refractive power in the transverse section: −0.0727. .

The free-form surface shape of the inner surface is the non-arc shape in the longitudinal section, the above formula:
Z = CH ² / [1 + √ {1- (1 + K) C ² H ² }]
The aspherical shape corresponding to the aspherical coefficient corresponding to the conic constant: K: Crx as “−1.213” is represented by “the center of curvature on the optical axis AX ( It is a surface shape obtained by rotating around an “axis parallel to the x direction through the PB point of 3 (a)”.

  Thus, by making the inner side surface into a free-form surface, the difference between the thickness D on the optical axis and the thickness T1 and T2 can be reduced to an absolute value of 0.32.

  The “shape in the transverse cross section” of the shade of Example 11 is the same as that of the comparative example, and thus the value of “Dy” is the same value as that of the shade of the comparative example.

  Similarly to Example 11, the value of thickness: T2 in Table 22 is the maximum thickness in the longitudinal section, and is a value at a position of 110 mm downward from the optical axis AX.

"Example 12"
The data of Example 12 is shown in Table 25 following Table 1.

  Other data of Example 12 is shown in Table 26 following Table 2.

  The twelfth embodiment is an example in which the outer surface of the shade according to the eighth embodiment is used as a free curved surface.

  The shade of the twelfth embodiment has a negative refracting power as a lens action like the shade of the eighth embodiment, and the refracting powers: Dx and Dy are both negative and small in absolute value of 0.0046. The thickness of the shade on the optical axis is as thin as 2 mm.

  The amount of astigmatic difference is as small as 0.0000 and is substantially zero.

  Also in Example 12, the value of refractive power: Dy in the cross section in the transverse direction is matched with the value of refractive power: Dx in the cross section in the longitudinal direction: −0.0046, and the astigmatic difference is substantially set to “0”. Yes.

The free-form surface shape of the outer surface is the non-arc shape in the cross section in the lateral direction, the above formula:
Z = CH ² / [1 + √ {1- (1 + K) C ² H ² }]
The aspherical shape given by the conic constant: K as the aspherical coefficient: Cry as “−0.02881” is expressed as “the center of curvature on the optical axis AX ( This is a surface shape obtained by rotating around an axis parallel to the y direction through the QA point of 3 (b).

  Thus, by making the outer side surface into a free-form surface, the difference between the thickness D on the optical axis and the thicknesses T1 and T2 can be reduced to an absolute value of 0.24.

  The “shape in the transverse cross section” of the shade of Example 12 is the same as that of the comparative example, and thus the value of “Dy” is the same value as that of the shade of the comparative example.

  The value of thickness: T1 in Table 24 is the size at a position forming 50 degrees with respect to the optical axis AX in the transverse section, and is the minimum value of the thickness in the transverse section.

  In the cross section in the lateral direction, the thickness at a position (γ = 10 degrees) forming 80 degrees with respect to the optical axis AX is 2 mm.

"Example 13"
The data of Example 13 is shown in Table 27 following Table 1.

  Other data of Example 13 is shown in Table 28 following Table 2.

  The thirteenth embodiment is an example in which the inner surface of the shade according to the ninth embodiment is used as a free curved surface.

  The shade of the thirteenth embodiment has a negative refracting power as a lens action like the shade of the ninth embodiment, and both the refracting powers Dx and Dy are negative and small in absolute value of 0.0046. The thickness of the shade on the optical axis is as thin as 2 mm.

  The amount of astigmatic difference is as small as 0.0000 and is substantially zero.

  Also in Example 13, the astigmatism difference is substantially set to “0” by matching the value of the refractive power: Dy in the transverse section with the value of the refractive power in the longitudinal section: −0.0046. .

The free-form surface shape of the inner surface is the non-arc shape in the cross section in the transverse direction, the above formula:
Z = CH ² / [1 + √ {1- (1 + K) C ² H ² }]
The aspherical shape given as an aspherical coefficient corresponding to the conic constant: K: Cry is set to “0.042”, and the “curvature center on the optical axis AX (FIG. It is a surface shape obtained by rotating around an axis parallel to the y direction through (QB point of (b)).

  Thus, by making the inner side surface into a free-form surface, the difference between the thickness on the optical axis: T and the thickness: T1, T2 can be reduced to 0.16 in absolute value.

  The shape of the shade of Example 13 in the transverse cross section is the same as that of the comparative example, and therefore the value of “Dy” is the same as that of the shade of the comparative example.

  The value of thickness: T1 in Table 24 is the size at a position forming 50 degrees with respect to the optical axis AX in the transverse section, and is the minimum value of the thickness in the transverse section.

  In the cross section in the transverse direction, the thickness at a position that forms 80 degrees with respect to the optical axis AX is 2 mm.

  As described above, according to the present invention, the following helmet shade and helmet can be realized.

[1]
The helmet shade 10 is arranged at the front portion of the helmet body 20, and both the outer surface 10 </ b> A and the inner surface 10 </ b> B are configured by a transparent plate that is a concave curved surface toward the inside of the helmet body 20, The concave curved surface forming the inner surface is symmetric in the left-right direction, the symmetric surface is symmetrical in the longitudinal direction, the plane parallel to the left-right direction and perpendicular to the longitudinal section including the optical axis AX is cross-sectional in the lateral direction. when the in effective visual field, astigmatism of the longitudinal section and the transverse cross-section 0.06 m ^-1 Ri der below, at least one of the inner and outer surfaces of the effective visual field, the helmet body concave toroidal surface der Ru helmet shade inward (examples 1-9).

[2]
[1] The helmet shade according to [1], wherein the absolute values of the refractive power Dx in the longitudinal section and the refractive power Dy in the lateral section are both 0.12 m ⁻¹ or less (Example 1). ~ 13).

[ 3 ]
The helmet shade according to [1] or [2], wherein one of the inner surface 10B and the outer surface 10A is a toroidal surface that is concave toward the inside of the helmet body, and the other is a free-form surface. (Examples 10 to 13).

[4]
[3] The helmet shade according to [11], wherein the inner side surface 10B is a concave toroidal surface toward the inside of the helmet body (Examples 11 and 13).

[5]
In the helmet shade according to any one of [1] to [4] , the refractive power of the longitudinal section: Dx and the refractive power of the transverse section: Dy in the effective visual field region are matched with the other, Shade for helmet with astigmatic difference of 0 (Examples 6 to 13).

[6]
In the helmet shade according to any one of [1] to [5] , the shade thickness: T in the effective visual field region is set to the thickness on the optical axis: T0.
(1) 0.3T0 ≦ T ≦ 2T0
A helmet shade satisfying the following requirements (Examples 1 to 13).

[7]
In the helmet shade according to any one of [1] to [6] , in the effective visual field region, the curvature radius of the outer surface: Rx1, the curvature radius of the inner surface: Rx2, in the transverse section, in the longitudinal section, The curvature radius of the outer surface: Ry1, the curvature radius of the inner surface: Ry2, the condition:
(2) 200 <Rx1 <1000, 200 <Rx2 <1000
(3) 70 <Ry1 <400, 70 <Ry2 <400
A helmet shade satisfying the following requirements (Examples 1 to 13).

[8]
In the helmet shade according to any one of [1] to [7] , the helmet body 20 includes attachment / detachment portions 11 and 12 to / from the helmet body 20 outside the horizontal viewing angle region. A helmet shade that is removable.

[9]
[8] The helmet shade according to [8] , which can be opened and closed with respect to the helmet body 20 with the left and right attaching / detaching portions 11 and 12 to the helmet body 20 as peristaltic base points.

[10]
A helmet 1 having the helmet shade 10 according to any one of [1] to [9] .

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments described above, and the invention described in the claims unless otherwise specified in the above description. Various modifications and changes are possible within the scope of the above.
For example, in the embodiment described above, the direction of the line of sight when the wearer looks forward at infinity and the optical axis of the shade are parallel, but the present invention is not limited to this, and the optical axis AX is relative to the line of sight. In FIG. 3, the shade can be arranged so as to incline to the left or the left by about ± 15 degrees.

  In this case, the astigmatic difference of the shades of the first to thirteenth examples described above is slightly larger than the value shown in the examples, but the influence is only about 5% change, and there is no practical problem. .

  The effects described in the embodiments of the present invention are merely a list of suitable effects resulting from the invention, and the effects of the present invention are not limited to those described in the embodiments.

1 Helmet
10 shades
10A outside surface
10B inner surface
AX optical axis
ξ Effective field area in the vertical direction (length of the effective field area in the vertical direction)
η Horizontal effective field area (length of the effective field area in the horizontal direction)
E Wearer's eyes

Japanese Patent No. 3593073

Claims (10)

A helmet shade disposed at the front of the helmet body, the outer side surface and the inner side surface are both formed by a transparent plate that is a concave curved surface toward the inner side of the helmet body, and the concave portion forming the outer side surface and the inner side surface. The curved surface is bilaterally symmetric in the left-right direction, and the effective field of view when the plane of symmetry is symmetrical in the vertical direction, the plane parallel to the left-right direction and perpendicular to the vertical cross-section including the optical axis in the region, the astigmatism of the transverse cross-section and the longitudinal cross section is 0.06 m ^-1 Ri der below,
A helmet shade in which at least one of an inner surface and an outer surface in an effective visual field region is a concave toroidal surface toward the inside of the helmet body. 2. The helmet shade according to claim 1, wherein the absolute values of the refractive power Dx in the longitudinal section and the refractive power Dy in the lateral section are both 0.12 m ⁻¹ or less . The helmet shade according to claim 1 or 2,
  One of the inner surface and the outer surface is a toroidal surface that is concave toward the inside of the helmet body, and the other one is a helmet shade that is a free-form surface. The helmet shade according to claim 3,
  A shade for helmets whose inner surface is a toroidal surface recessed toward the inside of the helmet body. The helmet shade according to any one of claims 1 to 4,
  A helmet shade having zero astigmatic difference by matching one of the refractive power of the longitudinal section and the refractive power of the lateral section in the effective visual field region with the other. The helmet shade according to any one of claims 1 to 5,
  The thickness of the shade in the effective visual field region: T is equal to the thickness on the optical axis: T0.
  (1) 0.3T0 ≦ T ≦ 2T0
Satisfaction helmet for shade. The helmet shade according to any one of claims 1 to 6,
  In the effective field of view, the curvature radius of the outer surface in the longitudinal section: Rx1, the curvature radius of the inner surface: Rx2, the curvature radius of the outer surface in the transverse section: Ry1, and the curvature radius of the inner surface: Ry2 are:
  (2) 200 <Rx1 <1000, 200 <Rx2 <1000
  (3) 70 <Ry1 <400, 70 <Ry2 <400
Satisfaction helmet for shade. The helmet shade according to any one of claims 1 to 7,
  A helmet shade that has an attachment / detachment portion to / from the helmet body outside the viewing angle region in the left / right direction, and is attachable / detachable to / from the helmet body by the attachment / detachment portion. The helmet shade according to claim 8,
  A helmet shade that can be opened and closed with respect to the helmet body, with the left and right attachment / detachment parts to the helmet body as the starting point. A helmet having the helmet shade according to any one of claims 1 to 9.

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