GB2288658A

GB2288658A - A vehicle lamp

Info

Publication number: GB2288658A
Application number: GB9507782A
Authority: GB
Inventors: Naoki Matsumura; Tsutomu Machida
Original assignee: Koito Manufacturing Co Ltd
Current assignee: Koito Manufacturing Co Ltd
Priority date: 1994-04-19
Filing date: 1995-04-13
Publication date: 1995-10-25
Anticipated expiration: 2015-04-13
Also published as: DE19514424B4; DE19514424A1; GB2288658B; GB9507782D0

Description

1 VEHICULAR MR LAMP LENS --CCWATIBLE- WITH TWO DIFFERENT KINDS OF LrGHT

SOURCES 2288658 This invention relates to electric lamps in general and, in particular, to those suitable for use as marker or signal lamps on motor vehicles, among other applications. More particularly, the invention deals with improvements in or relating to the lens of such lamps.

some vehicular lamps, such as automobile marker lamps, may employ as light sources either an incandescent lighting bulb or a multiplicity of light emitting diodes (LEDs) arrayed in columns and rows. Tisually, the incandescent bulb is used in combination with a paraboloidal reflector capable of translating the light emitted by the bulb into approximately parallel rays. Each LED, on the other hand, emits divergent rays of light.

Whichever type of light source is employed, automobile marker lamps rely on lenses for controlling the light into a desired beam pattern. Beam pattern standards differ for each particular automobile marker lamp. Tail lamps and stop lamps, for example, are required to produce beams at angles of divergence of 10 degrees in each of upward and downward directions, and 20 degrees in each of opposite lateral directions. High mounted stop lamps, on the other hand, must emit beams at angles of divergence of 10 degrees upward, five degrees downward, and 10 degrees in each of opposite lateral directions.

Lens configurations for each of the incandescent light source and the LED light source, designed to meet the beam pattern standards set forth above, are themselves not new in the art. Japanese Unexamined Patent Publication No. 1-319201 teaches 2 a lens having an array of nine lens steps for each LED. Lenses ha-ving a multiplicity of fisheye steps of prescribed radii of curvature in both vertical and horizontal directions have been used for modifying the parallel light rays of the incandescent light source into beams diverging both vertically and horizontally at required angles.

Thus., conventionally, the two entirely different lens configurations were needed for the two different light sources, because of the light rays of different characteristics produced by these light sources. Automobile marker lamp bodies may be so constructed that either the incandescent or LED light source may be selectively mounted thereto, with a view to the reduction of the manufacturing costs of such lamps. But then two different kinds of lenses have had to be prepared for the two different kinds of light sources, contrary to the objective of cost reduction in view.

It is therefore an object of this invention to provide a novel lamp lens configuration compatible with two different kinds of light sources.

According to the invention, stated in brief, there is provided an electric lamp for us& on motor vehicles, among other applications, wherein either first or second light source means is to be selectively mounted in a lighting chamber defined by a lamp body and a lens., the first light source means producing parallel rays of light, the second light source means including a plurality of light sources each producing divergent rays of light, characterized in that the lens is formed to include a set of steps for each light source of the second light source means, and that each set of steps include at least one functioning primarily 3 for diverging light rays emitted from a central part of one associated light source of the second light source means, ones functioning primarily for somewhat converging light rays efnitted from a peripheral part of one associated light source of the second light source means, and ones functioning primarily for diverging the parallel light rays from the first light source means.

Typically, the first light source means comprises an incandescent lighting bulb in combination with a paraboloidal reflector, and the second light source means comprises an array of LEDs. Whichever type of light source means is employed, the lens of the foregoing improved design functions to provide a required beam pattern. Thus the lamp body may be so constructed as to permit the mounting of either the first or the second light source means thereto. The manufacturing costs of vehicular lamps of this broad design will be greatly reduced by combining the larnp body with the compatible lens.

The above and other features and advantages of this invention and the manner of realizing them will become more apparent, and the invention itself will best be understood, from a study of the following description and appended claims, with reference had to the attached drawings wherein:

Figure 1 is a vertical section through an automobile high mounted stop lamp embodying the principles of this invention, the lamp being shown with both incandescent bulb means and LED means mounted therein for the purpose of illustration only; Figure 2 is a horizontal section through the stop lamp, the lamp, being here shown with only the incandescent bulb means mounted therein; i 4 Figure 3 is a view similar to Figure 2 except that the lamp ig 949-,7n with onlY the LED means mounted therein; Figure 4 is an enlarged, fragmentary front elevation of the lens of the Figures 1-3 stop 1 amp; Figure 5 is a horizontal section through the showing of Figure 4, taken along the line V-V therein; Figure 6 is a vertical section through the showing of Figure 4, taken along the line VI-VI therein; Figure 7 is a another horizontal section through the showing of Figure 4, taken along the line VII-VII therein; Figure 8 is another vertical section through the showing of Figure 4, taken along the line VIII-VIII therein; Figure 9 is an illustration, somewhat similar to Figure 4, explanatory of another preferred form of lens according to the invention; Figure 10 is also an illustration, somewhat similar to Figure 4, explanatory of still another preferred form of lens according to the invention; and Figure 11 is also an illustration explanatory of still another preferred form of lens according to thle invention.

The invention will now be described in detail as embodied in the automotive high mounted stop lamp shown in its entirety -in Figures 1-3 and therein generally designated 1. Mounted to the inside of an automobile rear windshield 2. the high mounted stop lamp 1 has a lamp body 3 of such construction as to permit the mounting of two different light source means to be sat forth subsequently.

Hereinafter in this specification the directional terms such as 11frontly and "rear", "forward" and "rearward", as well as der-.;vatives thereof, will be used with the understanding that the forward direction of the lamp 1 is to the left as viewed in Figures 1-3. Thus, for example, the lamp body 3 has a closed rear end 4 and an open front end 5, the latter being bonded directly to the windshield 2. The directional terms "upper" and,lower", nupwardll and "downward", and derivatives thereof will be used with the understanding that Figure 1 is a vertical section t-hrough the high mounted stop lamp 1. It will therefore be understood that the open front end 5 of the lamp body 3 is inclined to confo=n to the slant of the vehicle windshield 2, with its lower edge extending forwardly a considerable distance beyond its upper edge.

Closing the open front end 5 of the lamp body 3 is a compatible lens 6 forming the gist of this invention. Typically, the lens 6 may be molded from polycarbonate or acrylic resin, although other transparent plastics or like material may be employed as desired. The lamp body 3 and the lens 6 coact to define a lighting chamber 7.

The lamp body 3 is of such construction that the lamp 1 may have mounted in its lighting chamber 7 either first light source means comprising an incandescent lighting bulb 8, as In Figures 1 and 2, or second light source means comprising a plurality or 6 =Itiplicity of LEDs 9 and 9 1 an in Figures 1 and 3. The lens 6 is made ctible with both light source means according to the noy@l ConCeptS Of thlhl Inventign, an will be detailed subsequent- ly.

The incandescent bulb 8 is mounted in the lighting chamber 7 by having its base engaged in a mounting hole 10 in the closed end 4 of the 1 body 3. A paraboloidal reflector 11, another component of the first light source means, in also mounted in the lighting chamber 7 for translating the divergent light rays emitted by the bulb 8 into approximately parallel ones. The bulb mounting hole 10 is to be closed by suitable means, not shown, when the bulb 8 is not used.

At 12 is seen a printed circuit board which is mounted in the lighting chamber 7, in a position intermediate the opposite ends 4 and 5 of the lamp body 3, when the lamp 1 la used with the LED light source. The LEDs 9 and 9 1 are shown arrayed on the circuit board 12 in two rows, extending horizontally, and seven columns extendil ng vertically. The upper row of LEDs are designated 9, and the lower row of Ms, 9 1, in order to expedi. te the fo.'Llowing description of the lens 6.

The optical design of the lens 6 will be best understood from Figure 4 taken together with Figures 5-8, the latter figures being sections taken along the planes indicated by the corresponding Roman numerals in Figure 4. It will be noted, first of all, that the lens 6 is formed to include a multiplicity of steps of rectangular shape in an array. Such lens steps may be broadly divided into three groups designated 13,, 14 and 15, respectively, with various suffixes. The lens step group 13 is associated with the upper row of LEDs 9, and the lens step group 14 with the 7 lower row of LEDs 91. The lens step group 15 is disposed intermediate the other two groups of steps 13 and 14. These three groups of lens steps 13, 14 and 15 will be discussed in detail hereafter in that order.

The first group of lens steps comprises a set of nine lens steps 13ull, 13uc, 13ur, 13al, 13cc, 13cr, 1M1, 13dc and 13dr which are disposed forwardly of each LED 9 of the upper row in an array of three rows and three columns. The top and intermediate rows of lens steps are each 3.5 millimeters in both vertical and.horizontal dimensions whereas the bottom row of lens steps are each 1.75 millimeters in vertical dimension and 3.5 millimeters in horizontal dimension.

Lying centrally of each array of lens steps and just opposite one LED 9 of the upper row, the lens step 13cc functions primarily for somewhat diverging the coherent light rays from the central part of one associated LED 9. The lens step 13ec has a concave surface with radii of curvature of 8.5 millimeters in the horizontal direction and 9.2 millimeters, in the vertical direct-ion.

It will be further noted from Figure 6 that the lens step 13ce is inclined forwardly by 3' 24 1; that is, the lens step is thicker at its bottom end than at its top. The light from the center of one associated LED 9 is therefore refracted slightly downwardly.

The two lens steps 13u2 and 13ur, situated above and on both sides of the central step 13cc, are alike in having concave surfaces with radii of curvature of 6.0 millimeters in the horizon tal direction and 5.7 millimeters in the vertical direction.

1 a These lens steps 13ul and 13ur., particularly their hatched quarters neighboring the central step 13cc, function primarily for somewhat converging the divergent light rays from the peripheral parts of one associated LED 9 toward the center of the beam due to this LED. Ware it not for this function, the hatchad quarters of the lens steps 13ul and 13ur. an well as the hatched halves of the lens steps 13dl and 13dr, would appear inconveniently darker than the other parts of each array of lens steps, because each LED produces a divergent beam of circular cross section. The lens steps 13ul and 13ur are intended to make the complete lens surface approximately equal in luminosity when the LEDs are in use.

The two lens steps 13dl and 13dr, situated below and on both sides of the central step 13cc, are also alike in having concave surfaces with radii of curvature of 6.0 millimeters in the horizontal direction and 6.3 millimeters in the vertical direction. However, t. ese lens steps 13dU and 13dr have only half the vertical dimension of the lens steps of the upper two rows of the lens group 13, and the bottom ends of the lens steps 13dl and 13dr are at the deepest points of the concavities. Viewed in vert.Ical section as in Figure 8, therefore, the lens steps IMI and 13dr taper downwardly. The optical functions of the lens steps 13CU and 13dr, particularly their hatched halves neighboring the central step 13cc, are similar to those of the lens steps 13ul and 13ur.

The two lens steps 13cl and 13cr, lying on both lateral sides of the central step 13ec, have both concave surfaces with radii of curvature of 6.0 millimeters in the horizontal direction and 9.2 millimeters in the vertical direction. These lens steps 9 13cl and 13cr function primarily for diverging, both vertically and laterally, the parallel light rays from the incandescent light source means. However, the hatched halves of the le.ns steps 13cl and 13cr, contiguous to the central step 13cc, serve the additional purpose of somewhat converging the divergent light rays from the peripheral parts of one associated LED 9.

The lens step 13uc overlying the central stop 13= also functions primarily for diverging, both vertically and laterally, the parallel light rays from the incandescent light source means. However, the hatched half of the lens step 13uc, contiguous to the central step 13cc, serves the additional purpose of somewhat converging the divergent light rays from a peripheral part of one associated LED 9. The lens step 13= has a concave surface with radii of curvature of 8.5 millimeters in the horizontal direction and 5.7 millimeters in the vertical direction.

The lens step 13dc underlying the central step 13ec also functions primarily for diverging, both vertically and laterally, the parallel light rays from the incandescent light source means, and secondarily for somewhat converging the divergent light rays from a peripheral part of one associated LED 9. The lens step 13dc has a concave surface with radii of curvature of 8.5 millimeters in the horizontal direction and 6.3 millimeters in the vertical direction. However, the lens step 13dc has only half the vertical dimension of the lens steps of the upper two rows of the lens group 13, and its bottom end is at the deepest point of the concavity.

The second group of lens steps similarly comprises a set of nine lens steps 14ul, 14uc, 14ur, 14cl, 14cc, 14ar, 14d.1, 14dc and 14dr w.ltieh spin disposed fornrdly of each LID 21 9t the 119Wor row in an array of three rows and three columns. The inte-mediate and bottom rows of lens steps of this second group are each 3.5 millimeters in both vertical and horizontal dimensions, whereas the top row of lens stops are each 1.75 millimeters In vertical dimension and 3.5 millimeters in horizontal dimension.

Lying centrally of each array of lens steps and just opposite one LED 9 1 of the lower row, the lens stop 14ce functions primarily for somewhat diverging the coherent. light rays from the central part of one associated LED 9. The lens step 14cc has a concave surface with radii of curvature of 8,5 millimeters in the horizontal direction and 9.2 millimeters in the vertical direction.

It will be further noted from Figure 6 that the lens step 14cc is inclined rearwardly by 3 241; that is, the lens step is thicker at its top end than at its bottom. The light from the center of one associated LED 9 is therefore refracted slightly upwardly.

The two lens steps 14ul and 14ur, situated above and on bcth sides of the central step 14cc, are alike in having concave surfaces with radii of curvature of 6.0 millimeters in the horizontal direction and 5.7 millimeters in the vertical direction. However, these lens steps 14ul and 14ur have only half the vertical dimension of the lens steps of the upper two rows of the lens group 14, and the bottom ends of the lens steps 14ul and 14ur are at the deepest points of the concavities. These lens steps 14ul and 14ur, particularly their hatched halves neighboring the central step 14cc, function primarily for somewhat converging the 11 divergent light rays from the peripheral parts of one associated LED 9 1 toward the center of the beam due to this LED. The lens steps 14ul and 14ur are intended to make the complete lens surface approximately equal in luminosity when the LEDs 9 and 911 are in use.

The lens steps 1dul and 14ur are also inclined rearwardly by 3' 24 1, so that the light from the peripheral parts of one associated LED 91 is refracted slightly upwardly.

The two lens steps 14dI and 14dr, situated below and on both sides of the central step 14cc, are also alike in having concave surfaces with radii of curvature of 6. 0 millimeters in the horizontal direction and 6.3 millimeters in the vertical direction. The optical functions of the lens steps 14dl and 14dr, particularly their hatched quarters naighboring the central step 14cc, are similar to those of the lens steps 14ul and 14u= set forth above. The lens steps 14dl and 14dr are also inclined rearwardly by 3 0 24 1, so that the light from the peripheral parts of one associated Z2D 91 is refracted slightly upwardly.

The two lens steps 14cl and 14cr, lying on both lateral sides of the central step 14cc, have both concave surfaces with radii of curvature of 6.0 millimeters in the horizontal direction and 9.2 millimaters in the vertical direction. These lens steps 14cl and 14cr function primarily for diverging, both vertically and laterally, the parallel light rays from the incandescent light source means. However, the hatched halves of the lens steps 14cl and 14ar, contiguous to the central step 14cc, serve the additional purpose of somewhat converging the divergent light rays from the peripheral parts of one associated LED 9. The lens 1 12 steps 14 cl and 14cr are also inclined rearwardly by 3 24 1, so that the light from the peripheral parts of one associated LED 9 is refracted slightly upwardly.

The lens stop 14= overlying the central step 14ca also functions primarily for diverging, both vertically and laterally, the parallel light rays from the incandescent light source means, and secondarily for somewhat converging the divergent light rays fr= a peripheral part of one associated LED 9. The lens step 14= has a concave surface with radii of curvature of 8.5 millimeters in the horizontal direction and 7.0 millimeters in thle vertical direction.

The lens step 14dc underlying the central step 14cc also functions primarlily for diverging, both vertically and laterally, the parallel light rays from the incandescent light source means. However, the hatched half of the lens step 1Adc, contiguous to the central step 14cc, serves the additional purpose of somewhat converging the divergent light rays from a peripheral part of one associated LED 9. The lens step 14dc has a concave surface with radii of curvature of 8.5 millimeters in the horizontal direction and 6.3 millimeters in the vertical direction. The lens steps 14dc Is also inclined rearwardly by 3 241, so that the light from the peripheral part of one associated LED 91 is refracted slightly upwardly.

The third group of lens steps, aligned between the first and thle second groups of lens steps, function primarily for diverging, both vertically and laterally, the parallel light rays from the incandescent light source means. The lens step 15c, interposed between lens steps 13dc and 14uc, has a concave surface 13 with radii of curvature of 8.5 millimeters in the horizontal direction and 2.6 millimeters in the vertical direction. The lens steps 151 and 15r, located on both lateral sides of the lens step 15c, have both concave surfaces with radii of curvature of 3.9 millimeters in the horizontal direction and 3.4 millimeters in the vertical direction. All the third group of lens steps are 3.5 millimeters in both vertical and horizontal dimensions.

Such being the construction of the automobile high mounted stop lamp 1 according to the invention, the steps 13uc, 13c.1, 13cr, 13dc, 14uc, 14dI, 'Acr, 14dc, 151, 15c and 151 of the lens 6 function mostly to provide a required beam pattern when the lamp employs the incandescent lighting bulb 8 in combination with the reflector 11. When the lamp employs the LEDs 9 and gy, on the other hand, then the steps 13cc, 13ul, 13ur, 13cU, 13dr, 14cc, 14ul, 14ur, 14c11 and 14dr of the lens 6 function mostly to amend the divergent light ray& from all the LEDs into a required beam pattern. This one lens 6 is therefore corpat-ible with both light sourne means.

It will also be appreciated that the first or upper group of lens steps include the steps 13cc which refract the light downwardly, and the second or lower group of lens steps include the steps 14ac, 14ul, 14ur, 14dI, 14dr, 14cl, 14cr and 14dc which refract the light upwardly. Consequently, even though the front end of the lamp body, particularly its bottom edge, projects forwardly beyond the lens 6, the light that has traversed the lens is not to be blocked by such projecting part or parts of the lamp body or the like; instead, the light will he emitted with required angles of vertical divergence. Of course, as required, one or more steps of the first group, other than the steps 13cc, 14 could be made to refract light downwardly.

The provision of the third step group 15 in the Figure 4 lens configuration is not of absolute necessity. Figure 9 shows a modified step arrangement 6a according to the invention. This step arrangement does not have the third stop group but is similar to the Figure 4 arrangement in having a set of nine steps, arrayed in three rows and three columns, afor each LED, although some of the steps serve two or more LEDs. All the lens steps of FiLT.ire 9 are sirdlar to the first disclosed steps in having concavities confronting the light source means.

Each such set includes a step 16ca which is disposed just opposite one LED 9. This central step functions primarily for somewhat diverging the light rays from the central part of the LED.

In diagonally opposite positions of the central step 16= there are provided four steps 16ul, 16ur, 16dl and 16dr. Those quarters of these steps which are closest to the step 16= function to converge the divergent light rays from the peripheral parts of one associated LED, in order to assure constant brightness for the complete, lens surface.

Steps 16ua and 16dC above and below the central step 16cc, and steps 16cl and 16cr on both lateral sides of the central step 16cc, all function primarily for diverging, both vertically and laterally, the parallel light rays from the incandescent light source means. Those halves of these steps 16uc, 16dc, 16cl and 16cr which are contiguous to the central step 116= serve the additional purpose of somewhat converging the light rays from the peripheral parts of one associated LED.

In Figure 10 is shown another modified stop arrangement 6b according to the invention, featuring a act of twenty five steps, arrayed in five columns and five rows, for each LED 9 or 91. All these steps are also similar to those of the lens 6 in having concavities confronting the light source means.

Each set of the Figure 10 step arrangement 6b includes a central step 17C disposed just opposite one LED for somewhat diverging the light rays from the central part of the LED. Around this central step there are alternately provided eight steps 17Z, four steps 17LI, and twelve steps 17Y. The steps 171 and 17L, are alike in reducing the angles of divergence of the light rays from other than the central part of the LED.

However, the steps 1711 have a refraction angle greater than that of the stops 1U, in order to assure constant luminosity throughout the lens surface. The steps 17W are all for diverging the parallel light rays from the incandescent light source means both vertically and laterally. It will be seen that the Figure 10 step arrangement is largely analogous with that of Figure 4.

in still another modified step arrangement 6c shown in Figure 11, sets of steps 18 associated with the respective LEDs 9 and 91 are isolated from one another not only by horizontal rows of steps 19, but also by vertical columns of steps 191, for diverging the parallel light rays from the incandescent light source means. Each set 18 may comprise the nine steps of Figure 4 or 9 or the twenty five steps of Figure 10. As a further alternative, the sets of steps 18 may be isolated from one another 16 6P.1y by the Columna 9: Oteps 1.91p Despite the foregoing disclosure of sora specific embodiments, it is not desired that the invention be limited by the exact details of the drawings or the description thereof. For example, the lens steps could be formed not by concavities but by convexities or by cornbinations of concavities and convexities. Also, the LEDs could be replaced by electroluminescence elements, light conductors or the like. It in therefore appropriate that the invention be construed broadly and in a manner consistent with. the fair meaning or proper scope of the attached claims.

17

Claims

Claims:

1. An electric lamp for use on motor vehicles, among other applications, wherein either first or second light source means is to be selectively mounted in a lighting chamber defined by a lamp body an.d a lens, the first light source means producing parallel rays of light, the second light source means including a plurality of light sources each producing divergent rays of light, characterized in that the lens is formed to include a set of steps for each light source of the second light source means, and that each set of steps include at least one functioning primarily for diverging light rays emitted from central part of one associated light source of the second light source means, ones functioning primarily for somewhat converging light rays emitted from peripheral part of one associated light source of the second light source means, and ones functioning primarily for diverging the parallel light rays from the first light source means, whereby the lens is compatible with both first and second light source means.

2. An electric lamp as claimed in claim 1, characterized in that each set of steps of the lens are arrayed in columns extending in a first direction and rows extending in a second direction at right angles with the first direction, and that said one step functioning primarily for diverging the light rays from the central part of one associated light source of the second light source means is disposed centrally of the array and opposite the one associated light source of the second light source means.

3. An electric lamp as claimed in claim 2, characterized in that the steps functioning primarily for somewhat converging is the light rays emitted from the peripheral part of one associated light source of the second light source means are disposed in diagonally opposite positions of said one stop, and that the steps functioning primarily for diverging the parallel light rays from the first light source means are disposed both in opposite positions of said one step in the first direction and in opposite positions of said one stop in the second direction.

4. An electric lamp as claimed in any of the preceding claims, wherein the light sources of the second light source means are arranged in at least two rows, characterized in that the lens in formed to include a row of steps interposed between the sets of steps for diverging the parallel light rays from the first light source means.

5. An electric lamp as claimed in any of the preceding claims, wherein the light sources of the second light source means are arranged in at least two rows, characterized in that at least one of each sat of lens steps for each of one row of light sources _Js configured to refract light in one. direction, and that at least one of each sat of lens steps for each of the other row of light sources is configured to refract light in another direction opposite to said one direction.

6. An electric lamp as claimed in any of the preceding claims, wherein the sets of steps are arranged in columns and rows, characterized in that the sets of steps are isolated from one another by columns and rows of steps for diverging the parallel light rays from the first light source means.

7. An electric lamp for use on motor vehicles, among other applications, wherein either first or second light source means 19 4 s to be selectively mounted in a lighting chamber defined by a lamp body and a lens, the first light source means producing parallel rays of light, the second light source means including a plurality of light sources each producing divergent rays of light, characterized in that the lens is formed to include a set of steps in an array of five columns and five rows for each light source of the second light source means, and that each set of steps include one disposed centrally of the array and functioning primarily for diverging the light rays from central part of one associated light source of the second light source means, and, around said one step, ones functioning primarily for somewhat converging light rays from other than the central part of one associated light source of the second light source means, and ones functioning primarily for diverging the parallel light rays from the first light source means, whereby the lens is compatible with both first and second light source means.

8. An electric lamp as claimed in claim 7, characterized in that said steps of each step functioning primarily for converging the light rays are subdivided into a first group for converging the light rays at a first refraction angle, and a second group for converging the light rays at a second refraction angle greater than the first refraction angle, the first group of steps being disposed mostly closer to said one step.