CA1197496A - Reflector lamp with shaped reflector and lens - Google Patents
Reflector lamp with shaped reflector and lensInfo
- Publication number
- CA1197496A CA1197496A CA000392739A CA392739A CA1197496A CA 1197496 A CA1197496 A CA 1197496A CA 000392739 A CA000392739 A CA 000392739A CA 392739 A CA392739 A CA 392739A CA 1197496 A CA1197496 A CA 1197496A
- Authority
- CA
- Canada
- Prior art keywords
- reflector
- light source
- lamp
- light
- lens
- 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.)
- Expired
Links
Classifications
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- 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
- F21V13/00—Producing particular characteristics or distribution of the light emitted by means of a combination of elements specified in two or more of main groups F21V1/00 - F21V11/00
- F21V13/02—Combinations of only two kinds of elements
- F21V13/04—Combinations of only two kinds of elements the elements being reflectors and refractors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F21—LIGHTING
- F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
- F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
- F21S41/30—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by reflectors
- F21S41/32—Optical layout thereof
- F21S41/33—Multi-surface reflectors, e.g. reflectors with facets or reflectors with portions of different curvature
- F21S41/331—Multi-surface reflectors, e.g. reflectors with facets or reflectors with portions of different curvature the reflector consisting of complete annular areas
- F21S41/333—Multi-surface reflectors, e.g. reflectors with facets or reflectors with portions of different curvature the reflector consisting of complete annular areas with discontinuity at the junction between adjacent areas
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- 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
- F21V7/00—Reflectors for light sources
- F21V7/04—Optical design
- F21V7/09—Optical design with a combination of different curvatures
Abstract
REFLECTOR LAMP WITH SHAPED REFLECTOR AND LENS
Abstract of the Disclosure A reflector lamp with a shaped reflector and lens. The reflector is generally parabolic, to reflect light frontwardly. Some of the direct light from the light source is not reflected, and diverges in a beam pattern that would be wasted; the lens refracts this divergent light in a more frontwardly and useful direction. For a flood light, the lens converges the reflected light rays into a cross-over pattern to provide a flood beam pattern.
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Abstract of the Disclosure A reflector lamp with a shaped reflector and lens. The reflector is generally parabolic, to reflect light frontwardly. Some of the direct light from the light source is not reflected, and diverges in a beam pattern that would be wasted; the lens refracts this divergent light in a more frontwardly and useful direction. For a flood light, the lens converges the reflected light rays into a cross-over pattern to provide a flood beam pattern.
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Description
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- l - LD 853 REFLECTOR'LAMP'WITH SHAPED REFLECTOR AND LENS
~ _ _ _ _ _ Refe'rence''to'Rela'ted _pp'l'ica'tion Serial No. 381,080, filed July 3, 1981, Reiling, Putz, and VanHorn, "Reflector Lamp", assigned the same as this invention.
~'ackground o-f the Invention The invention is in the field of reflector lamps, such as flood lights and spot lights, having reflectors and lenses. In such lamps, the light source is deeply recessed in a concave reflector which reflects frontwardly in a desired beam pattern substantially more than half of the total light output of the lamp.
The above-referenced patent application discloses a reflector lamp having a concave reflector comprising parabolical and spherical sections, for pro~ecting a pattern of parallel light rays in a frontward direction.
In the use of a concave reflector lamp, there is an undesirably wasted amount of light which emanates from the light source and is not reflected but radiates in a divergent cone pattern through the front of the reflector.
,g7~6
- l - LD 853 REFLECTOR'LAMP'WITH SHAPED REFLECTOR AND LENS
~ _ _ _ _ _ Refe'rence''to'Rela'ted _pp'l'ica'tion Serial No. 381,080, filed July 3, 1981, Reiling, Putz, and VanHorn, "Reflector Lamp", assigned the same as this invention.
~'ackground o-f the Invention The invention is in the field of reflector lamps, such as flood lights and spot lights, having reflectors and lenses. In such lamps, the light source is deeply recessed in a concave reflector which reflects frontwardly in a desired beam pattern substantially more than half of the total light output of the lamp.
The above-referenced patent application discloses a reflector lamp having a concave reflector comprising parabolical and spherical sections, for pro~ecting a pattern of parallel light rays in a frontward direction.
In the use of a concave reflector lamp, there is an undesirably wasted amount of light which emanates from the light source and is not reflected but radiates in a divergent cone pattern through the front of the reflector.
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2- LD 8534 Summary of the Invention Objects of the invention are to provide a reflector lamp, combined with a lens, having improved optical efficiency which permits a design having lower power consumption~ and to achieve this with a reasonably compact lamp.
The invention comprises, briefly and in a preferred embodiment, a reflector lamp having a concave reflector, which may have one or more parabolic sections, for reflecting light Erontwardly from a light source located at the focal point. The light source is deeply recessed in the reflector so as to be at least three time~ as far from the Eront opening Oe the reflector as from the reflector's vertex or virtual vertex, so that substantially more than half of the total light is re~lected by the reflector. A lens i~
positioned over the front of the reflector and is contoured at least near the outer edge thereof to refract frontwardly at leas~ some o~ the non-reflected divergent light emanating directly from the light source. ~or a flood light, substantially the entire lens is contoured to refract and converge light rays including the reflected light rays, so that the reflected light rays converge into a cross-over pattern to prov ide a flood beam pattern.
Brief Description_of the Drawing .
Figure l is a front view of a re~le~tor lamp in accordance with a preferred embodiment of the invention.
~ iyure 2 is a cross section side view taken on the line 2-2 of Figure l.
~L9~7~6
The invention comprises, briefly and in a preferred embodiment, a reflector lamp having a concave reflector, which may have one or more parabolic sections, for reflecting light Erontwardly from a light source located at the focal point. The light source is deeply recessed in the reflector so as to be at least three time~ as far from the Eront opening Oe the reflector as from the reflector's vertex or virtual vertex, so that substantially more than half of the total light is re~lected by the reflector. A lens i~
positioned over the front of the reflector and is contoured at least near the outer edge thereof to refract frontwardly at leas~ some o~ the non-reflected divergent light emanating directly from the light source. ~or a flood light, substantially the entire lens is contoured to refract and converge light rays including the reflected light rays, so that the reflected light rays converge into a cross-over pattern to prov ide a flood beam pattern.
Brief Description_of the Drawing .
Figure l is a front view of a re~le~tor lamp in accordance with a preferred embodiment of the invention.
~ iyure 2 is a cross section side view taken on the line 2-2 of Figure l.
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-3- LD 8534 Figure 3 is a side view of the lamp and a flood 1 ight beam pattern.
Description of the Preferred Embodiment A preferred embodiment of the inventic)n, as shown in the drawing, comprises a ref.lector lamp having a S concave reflector 11 shaped to have a front reflector section 12 which has a parabolic contour w.ith respect to a focal point 13, an intermediate reflector section 14 which has a spherical contour with respect to the focal point 13, and a rear reflector sectioll 15 which has a parabolic contour with respect to the focal point 13.
The cross-section of the reflector 11 perpendicular to its principal optical axis is circular, as shown in Figure 1. Thus, each of the three reflector sections is defined by a surface of revolution of a parabolic or a circular curveO A ~ilament 16 is centered at the focal point 13 and pre~errably is located in or near the plane 17 of~mutual truncation at th~ joinder o~ the front section 12 and inte-mediate section 14, as shown in the drawing.
To achieve the maximum practical optical ; efficiency, reflector lamps are designed to have the reflector 11 as deep as is feasible, to provide a large area of the primary re1ecting surface 1~ for refleeting substantially more than half of the total light into the desired beam pattern and so that substantially less than half of the total amount of light emanates directly and ~reflected from the light source 16 through the fron~
of the reflector in a divergent pattern whereby s~me of the light is wasted because it falls outside of the desired beam pattern. Thus, the light source 16 is deeply recessed in the reflector and is typically at
Description of the Preferred Embodiment A preferred embodiment of the inventic)n, as shown in the drawing, comprises a ref.lector lamp having a S concave reflector 11 shaped to have a front reflector section 12 which has a parabolic contour w.ith respect to a focal point 13, an intermediate reflector section 14 which has a spherical contour with respect to the focal point 13, and a rear reflector sectioll 15 which has a parabolic contour with respect to the focal point 13.
The cross-section of the reflector 11 perpendicular to its principal optical axis is circular, as shown in Figure 1. Thus, each of the three reflector sections is defined by a surface of revolution of a parabolic or a circular curveO A ~ilament 16 is centered at the focal point 13 and pre~errably is located in or near the plane 17 of~mutual truncation at th~ joinder o~ the front section 12 and inte-mediate section 14, as shown in the drawing.
To achieve the maximum practical optical ; efficiency, reflector lamps are designed to have the reflector 11 as deep as is feasible, to provide a large area of the primary re1ecting surface 1~ for refleeting substantially more than half of the total light into the desired beam pattern and so that substantially less than half of the total amount of light emanates directly and ~reflected from the light source 16 through the fron~
of the reflector in a divergent pattern whereby s~me of the light is wasted because it falls outside of the desired beam pattern. Thus, the light source 16 is deeply recessed in the reflector and is typically at
4!~
least three times the distance from the front plane or rim 31 of the reflector than from the vertex, or virtual vertex 12l in the embodiment shown, of the primary relecting surface 12. The desired long depth of the reflector is limited by practical considerations such as not wanting unduly great size, weight, bulk, and cost of the reflector. Alternative light sources may be employed in place of the filament 16, such as a halogen regenerative-cycle incandescent lamp or an arc discharge lamp. A shaped lens 20 is placed or sealed over the front opening of the reflector 11, primarily to modify the light pattern, will be described, and also to protect the reflecting surface and keep it clean, and a c~ver or lens is required if the light source is a bare filament 16 in the reflector. The reflector 11 may be made of molded glass, its inner surface being coated with aluminum or silver to provide a reflective surface, and the filament 16 preferrably is made of tungsten and is mounted on a pair of lead-in support wires 18, 19 of suitable material such as molybdenum.
Light rays which emanate from the light source 16 at the focal point 13 and which strike the parabolic front reflector section 12, will be reflected in a generally frontward direction, as indicated by the light ray paths 21. Similarly, light rays 22 emanating from the filament 16 and which strike the parabolic rear reflector section 15, will be reflected generally frontwardly.
As is disclosed and claimed in the above-referenced patent application, the spherical intermediate section 14 is dimensioned with respect to the parabolic front reflector section 12 so that all, or substantially all, of the light emanating from the light
least three times the distance from the front plane or rim 31 of the reflector than from the vertex, or virtual vertex 12l in the embodiment shown, of the primary relecting surface 12. The desired long depth of the reflector is limited by practical considerations such as not wanting unduly great size, weight, bulk, and cost of the reflector. Alternative light sources may be employed in place of the filament 16, such as a halogen regenerative-cycle incandescent lamp or an arc discharge lamp. A shaped lens 20 is placed or sealed over the front opening of the reflector 11, primarily to modify the light pattern, will be described, and also to protect the reflecting surface and keep it clean, and a c~ver or lens is required if the light source is a bare filament 16 in the reflector. The reflector 11 may be made of molded glass, its inner surface being coated with aluminum or silver to provide a reflective surface, and the filament 16 preferrably is made of tungsten and is mounted on a pair of lead-in support wires 18, 19 of suitable material such as molybdenum.
Light rays which emanate from the light source 16 at the focal point 13 and which strike the parabolic front reflector section 12, will be reflected in a generally frontward direction, as indicated by the light ray paths 21. Similarly, light rays 22 emanating from the filament 16 and which strike the parabolic rear reflector section 15, will be reflected generally frontwardly.
As is disclosed and claimed in the above-referenced patent application, the spherical intermediate section 14 is dimensioned with respect to the parabolic front reflector section 12 so that all, or substantially all, of the light emanating from the light
-5- LD 8534 source 16 and which strikes the spherical intermediate section 14 r will be reElected thereby in a direction so as to strike the parabolic Eront sect.ion 12 and be re-reflected thereby in a generally frontward direct1on.
For example, a light ray 26 emanating from the light source 16 at the ~ocal point 13 of the reflector, strikes the intermediate spherical seotion 14 and is reflected back along its path and through the focal point 13, and strikes the parabolic front reflector section 12 and is directed frontwardly as indicated by previously mentioned the light ray path 21.
A preferred method of designing the reflector, i5 to first design the front section 12 and then design the contour of the spherical section 14. Next, a line is drawn from the rim 31, and through the focal point 13~
to the contour line of the intermediate section 14; this point of intersection establ.ishes the joinder pl~ne 28 at the rear of the section 14 where it joins the rear section 15. Thus the light ray 32 emanating from the fooal point 13 and which strikes the spherical intermediate section 14 at or adjacent to its rear plane 28, will be reflected back along its path and through .
the focal point 13, and strikes the parabolic front section 12 at or near its front rim 31 and i5 directed : 25 frontwardly as indicated at-32'. Another such light ray 32, 32' is show~ at the opposite side o~ the reflector.
In scientific optical terminology, the breadth of the parabolic reflector curve at the focal point 13 is the latus rectum and is represented in the drawin~ by the line 17 in Fig. 2, ana ~he vertex is ~he poîn~ on the rear surface directly behind the focal point 13.
The vertex of the front parabolic section 12 is the point thereon that would be directly behind the fo~al point 13 if the parabolic curvature were to be continued ~7~fi
For example, a light ray 26 emanating from the light source 16 at the ~ocal point 13 of the reflector, strikes the intermediate spherical seotion 14 and is reflected back along its path and through the focal point 13, and strikes the parabolic front reflector section 12 and is directed frontwardly as indicated by previously mentioned the light ray path 21.
A preferred method of designing the reflector, i5 to first design the front section 12 and then design the contour of the spherical section 14. Next, a line is drawn from the rim 31, and through the focal point 13~
to the contour line of the intermediate section 14; this point of intersection establ.ishes the joinder pl~ne 28 at the rear of the section 14 where it joins the rear section 15. Thus the light ray 32 emanating from the fooal point 13 and which strikes the spherical intermediate section 14 at or adjacent to its rear plane 28, will be reflected back along its path and through .
the focal point 13, and strikes the parabolic front section 12 at or near its front rim 31 and i5 directed : 25 frontwardly as indicated at-32'. Another such light ray 32, 32' is show~ at the opposite side o~ the reflector.
In scientific optical terminology, the breadth of the parabolic reflector curve at the focal point 13 is the latus rectum and is represented in the drawin~ by the line 17 in Fig. 2, ana ~he vertex is ~he poîn~ on the rear surface directly behind the focal point 13.
The vertex of the front parabolic section 12 is the point thereon that would be directly behind the fo~al point 13 if the parabolic curvature were to be continued ~7~fi
-6- LD 8534 behind the focal point 13. Thus the focal point 13 is relatively close to the vertex of the front parabolic curve 12 and is substantially farther from the vertex of the rear parabolic curve 15~ The diameter of the S spherical intermediate section 14 is essentially equal to the length of the latus rectum 17 of the front parabolic curve 12.
Due to the elongated shape of the filament 16, not all the light from different parts of the filament is emitted at the focal point 13, and therefore, will be reflected at slightly different anyles at any specific point of the reflector. As a sonsequence not all of the reflected light from the intermediate section 14 will pass through the focal point 13. Therefore the optical performance of the reflector will be somewhat degraded from that which would be obtained ~rom a hypothetical point source at the focal point 13.
The space defined and surrounded by the spherical intermediate section 14 provides a recess for accommoda-ting the light source 16, and spaces the reflectingsurface at the back part of the reflector suf~iciently far way from the filament 16 to minimize bIackening thereof by evaporated filament material, and accomplishes this while retaining an optical efficiency substantially as good as if the entire reflector had a : single parabolic curvature.
Some of the light emanating from the souxce 16 is not reflected by the reflector 11, and emerges from the source 16 in a diverging cone-shaped beam, illustrated by the cone edge pairs of light rays 33. Another illustrative pair of diverying light rays 34 within the aforesaid cone-shaped beam~ are also shown. This con~-shaped heam, including the cone edge-defining rays ~1~7~96
Due to the elongated shape of the filament 16, not all the light from different parts of the filament is emitted at the focal point 13, and therefore, will be reflected at slightly different anyles at any specific point of the reflector. As a sonsequence not all of the reflected light from the intermediate section 14 will pass through the focal point 13. Therefore the optical performance of the reflector will be somewhat degraded from that which would be obtained ~rom a hypothetical point source at the focal point 13.
The space defined and surrounded by the spherical intermediate section 14 provides a recess for accommoda-ting the light source 16, and spaces the reflectingsurface at the back part of the reflector suf~iciently far way from the filament 16 to minimize bIackening thereof by evaporated filament material, and accomplishes this while retaining an optical efficiency substantially as good as if the entire reflector had a : single parabolic curvature.
Some of the light emanating from the souxce 16 is not reflected by the reflector 11, and emerges from the source 16 in a diverging cone-shaped beam, illustrated by the cone edge pairs of light rays 33. Another illustrative pair of diverying light rays 34 within the aforesaid cone-shaped beam~ are also shown. This con~-shaped heam, including the cone edge-defining rays ~1~7~96
-7- LD 8534 33 and all other rays such as rays 34 contained therein would, but for the lens 20, emerge through the front of the reflector 11 in straight continuation rays 33', 34'.
All of the light rays of the cone-shaped beam, except for those on the optical axis, are divergent and inconsistent with the desired frontward parallel ray pattern provided by the reflec:tor 11, and (but for the lens 20) will fall outside the desired beam pattern and will be wasted light in most applicationsO The closer the cone rays are to the edge defining rays 33, the more divergent they will be, these edge rays 33 being the most divergent and other cone rays such as rays 34 which are slightly within t~e cone edge rays 33 being only sligh~ly less divergent.
The light rays 21, 32, 33, and 34 are shown as pairs thereof symmetrically arranged about the optical axis of the reflector llr to better illustrate the light distribution patterns in the cross-sectional view of Fig. 2 and to facilitate illustration in Fig. 3 of a projected flood l;ight beam pattern.
In accordance with the present invention, the lens 20 is contoured, at least near its outer rim, to refract in a more frontward direction at least some of the divergent "stray" light rays from the light source, and the lens may be further contourèd to provide a flood light beam pattern. The preferred contouring o~ the lens is in the form of concentric prisms 36; preferably on its inner surface, of the Fresnel lens type.
In ~ig. 2, the dashed-line light ray representations 21, 32, 33, etc. represent light rays from the source 16, both reflected and non-reflected within the reflector 11, and the dashed-line representations indicated by primed numbers 21', 32~, 33', etc. of these light rays in front of the light unit ....
All of the light rays of the cone-shaped beam, except for those on the optical axis, are divergent and inconsistent with the desired frontward parallel ray pattern provided by the reflec:tor 11, and (but for the lens 20) will fall outside the desired beam pattern and will be wasted light in most applicationsO The closer the cone rays are to the edge defining rays 33, the more divergent they will be, these edge rays 33 being the most divergent and other cone rays such as rays 34 which are slightly within t~e cone edge rays 33 being only sligh~ly less divergent.
The light rays 21, 32, 33, and 34 are shown as pairs thereof symmetrically arranged about the optical axis of the reflector llr to better illustrate the light distribution patterns in the cross-sectional view of Fig. 2 and to facilitate illustration in Fig. 3 of a projected flood l;ight beam pattern.
In accordance with the present invention, the lens 20 is contoured, at least near its outer rim, to refract in a more frontward direction at least some of the divergent "stray" light rays from the light source, and the lens may be further contourèd to provide a flood light beam pattern. The preferred contouring o~ the lens is in the form of concentric prisms 36; preferably on its inner surface, of the Fresnel lens type.
In ~ig. 2, the dashed-line light ray representations 21, 32, 33, etc. represent light rays from the source 16, both reflected and non-reflected within the reflector 11, and the dashed-line representations indicated by primed numbers 21', 32~, 33', etc. of these light rays in front of the light unit ....
- 8 - ID 8534 indicate what the ray patterns and directions would be without the presence of the lens 20. The solid-line representations, indicated by double-prirned numbers 21", 32", 33", etc. of these light rays in front of the lens 20 indicate their patterns and d:irections as modified by the functioning of the lens in accordance with the invention.
In accordance with the frist-men-tioned embodiment of the invention, the concentric prisms 36 are provided on the inner surEace of the lens 20 and only near the outer periphery thereof, for exarnple in an outer region of the lens so as to intercept all of the divergent light rays between and including the rays 33 and 3a~. These prisms 36 are shaped to be optically convergent, so as to refract the divergent light rays 33, 34 and the divergent rays therebetween, in a more frontward direction as indicated by the solid-line rays 33" and 34", and thus more nearly into the desired useful overall beam pattern.
At the same time, the reflected and frontwardly directed light rays between and including the rays 21, 32 will be converged inwardly by the lens prisms, as indicated by the solid-line rays 21" and 32", and will cross over at a region 38 (Fig. 3) in front of the lens 20 and thereafter be divergent and directed somewhat out of the desired beam pattern. A compromise can be found in the lens design and its degree of optical convergence, so that more useful light is gained in the desired overall beam pattern by the frontward refraction of the otherwise divergent rays 32', 33' than may be lost due to the convergent refraction of the otherwise parallel rays 21', 32'. This increases the useful light output and/or permits the use of a lower wattage filament 16 thus conserving electrical energy. In this embodiment of providing a lens 20 with concentric prisms 36 only ~ 9 - LD 8534 near the periphery of the lens, the reflected and non-reflected light rays from filament 16 which pass through the lens cen~ral region, such as defined by a circumference bounded by the light rays 21, are substantially unaffected by the lens.
In another embodiment of the invention, a flood lamp having improved electrical and optical efficiency is achieved by providing the light-reEracting concentric prisms 36 over substantially the entire inner surface of the lens 20, as shown in Fig. 2. These prisms need not be provided at the reflector's center area 41 where they would be relatively ineffective. Referring again to Fig. 3, in accordance with the flood light of the invention, the lens 20 refracts the non-reflected divergent light rays in a more frontwardly divergent pattern, exemplified by the light rays 33" and 34", which is in the desired divergent floodlight beam pattern. Also, the lens 20 refracts the reflected parallel light beams in a con~ergent manner to produce a cross-over pattern of rays which thereafter are divergent in the desired flood light pattern. For example, the above-described light rays 21" and 32"
cross over at region 38 in front of the lens 20 and thereafter diverge generally in the desired flood light beam pattern. For more completeness, Fig. 3 shows an additional pair of projected light rays 42" and 43"
which have been reflected by the reflector 11 toward the lens 20 at an intermediate diameter region 44 thereof and refracted by the lens to converge and cross over at a region 46 in front of the lens and thereafter diverge generally in the desired beam pattern. Unreflected light rays passing through the lens at its intermediate diameter region 44 will be refracted and projected approximately frontwardly, thus contributing to the ` ~9'7~
~10- LD 8534 overall flood beam illumination. In lamps built according to the invention, the crossover regions 38~ 46 lay in the range of about 5 to 20 inches in front of the lens 20.
A unique feature of the invention is the di~ergent projection of some light rays 33" and 34" and the convergent projection of ot:her light rays 21", 32", 42", and 43" which light rays cross over and become divergent in a manner compatible with the divergent rays 33" and 34" to provide a desired flood light beam pattern. The concentric prisms 36 need not have identical refra~tion angles; the refraction angles of ~ome or all of the various prisms can be different fron one another to tailor the light distribution for uniform intensity or other desired characteristics in the projcted light beam. By thus providing the lens 20, in cooperation with the reflector 11, most of the projected light rays are in the desired beam pattern and relatively little light is wasted, thus improving efficiency and conserving electrical energy.
While preferred embodiments o~ the invention have been shown and described, various other embodiments and : modifications thereof will be come apparent to persons skilled in the art, and will fall within the scope of the invention as defined in the followiny claims.
In accordance with the frist-men-tioned embodiment of the invention, the concentric prisms 36 are provided on the inner surEace of the lens 20 and only near the outer periphery thereof, for exarnple in an outer region of the lens so as to intercept all of the divergent light rays between and including the rays 33 and 3a~. These prisms 36 are shaped to be optically convergent, so as to refract the divergent light rays 33, 34 and the divergent rays therebetween, in a more frontward direction as indicated by the solid-line rays 33" and 34", and thus more nearly into the desired useful overall beam pattern.
At the same time, the reflected and frontwardly directed light rays between and including the rays 21, 32 will be converged inwardly by the lens prisms, as indicated by the solid-line rays 21" and 32", and will cross over at a region 38 (Fig. 3) in front of the lens 20 and thereafter be divergent and directed somewhat out of the desired beam pattern. A compromise can be found in the lens design and its degree of optical convergence, so that more useful light is gained in the desired overall beam pattern by the frontward refraction of the otherwise divergent rays 32', 33' than may be lost due to the convergent refraction of the otherwise parallel rays 21', 32'. This increases the useful light output and/or permits the use of a lower wattage filament 16 thus conserving electrical energy. In this embodiment of providing a lens 20 with concentric prisms 36 only ~ 9 - LD 8534 near the periphery of the lens, the reflected and non-reflected light rays from filament 16 which pass through the lens cen~ral region, such as defined by a circumference bounded by the light rays 21, are substantially unaffected by the lens.
In another embodiment of the invention, a flood lamp having improved electrical and optical efficiency is achieved by providing the light-reEracting concentric prisms 36 over substantially the entire inner surface of the lens 20, as shown in Fig. 2. These prisms need not be provided at the reflector's center area 41 where they would be relatively ineffective. Referring again to Fig. 3, in accordance with the flood light of the invention, the lens 20 refracts the non-reflected divergent light rays in a more frontwardly divergent pattern, exemplified by the light rays 33" and 34", which is in the desired divergent floodlight beam pattern. Also, the lens 20 refracts the reflected parallel light beams in a con~ergent manner to produce a cross-over pattern of rays which thereafter are divergent in the desired flood light pattern. For example, the above-described light rays 21" and 32"
cross over at region 38 in front of the lens 20 and thereafter diverge generally in the desired flood light beam pattern. For more completeness, Fig. 3 shows an additional pair of projected light rays 42" and 43"
which have been reflected by the reflector 11 toward the lens 20 at an intermediate diameter region 44 thereof and refracted by the lens to converge and cross over at a region 46 in front of the lens and thereafter diverge generally in the desired beam pattern. Unreflected light rays passing through the lens at its intermediate diameter region 44 will be refracted and projected approximately frontwardly, thus contributing to the ` ~9'7~
~10- LD 8534 overall flood beam illumination. In lamps built according to the invention, the crossover regions 38~ 46 lay in the range of about 5 to 20 inches in front of the lens 20.
A unique feature of the invention is the di~ergent projection of some light rays 33" and 34" and the convergent projection of ot:her light rays 21", 32", 42", and 43" which light rays cross over and become divergent in a manner compatible with the divergent rays 33" and 34" to provide a desired flood light beam pattern. The concentric prisms 36 need not have identical refra~tion angles; the refraction angles of ~ome or all of the various prisms can be different fron one another to tailor the light distribution for uniform intensity or other desired characteristics in the projcted light beam. By thus providing the lens 20, in cooperation with the reflector 11, most of the projected light rays are in the desired beam pattern and relatively little light is wasted, thus improving efficiency and conserving electrical energy.
While preferred embodiments o~ the invention have been shown and described, various other embodiments and : modifications thereof will be come apparent to persons skilled in the art, and will fall within the scope of the invention as defined in the followiny claims.
Claims (25)
1. A lamp comprising a concave reflector having a front section substantially defined by the surface of revolution of a first parabolic curve whose focal point is relatively close to its vertex with the surface terminating essentially at its latus rectum, an intermediate section of substantially spherical configuration having its center substantially at the focal point of said front section and a diameter essentially equal to the length of said latus rectum, a rear section substantially defined by a surface of revolution of a second parabolic curve whose focal point is substantially farther from its vertex than said first parabolic curve with said two focal points being substantially coincident, and a finite light source positioned substantially at said substantially coincident focal points wherein said rear section terminates at the circular junction with said spherical intermediate section so that substantially all light rays from said light source which are reflected by said spherical intermediate section are re-reflected by said parabolic front section.
2. A lamp as claimed in claim 1 wherein a lens means is attached to the remote edge of said front section.
3. A lamp as claimed in claim 1 wherein said finite light source lies substantially in the plane of said latus rectum.
4. A lamp as claimed in claim 1 wherein said finite light source lies substantially in a plane parallel to the plane of said latus rectum and is located spatially therefrom at a distance not greater than ten times the maximum light source dimension which is perpendicular to the light source major axis.
5. A lamp as claimed in claim 1 wherein said finite light source lies substantially in a plane perpendicular to the plane of said latus rectum and intersects said substantially coincident focal points.
6. A lamp as claimed in claim 1 wherein said finite light source lies substantially in a plane perpendicular to the plane of said latus rectum and is located spatially from said substantially coincident focal points at a distance not greater than ten times the maximum light source dimension which is perpendicular to the light source major axis.
7. A lamp as claimed in claim 1 wherein said center of said spherical section is located between said substantially coincident focal points of said parabolic sections and a point spaced therefrom located not greater than ten times the maximum light source dimension which is perpendicular to the light source major axis.
8. A reflector lamp comprising a finite light source positioned substantially at the focal point of a reflector, said reflector having a substantially parabolic front section as a primary reflecting surface, a substantially spherical intermediate section, and a substantially parabolic rear section, each of said sections having substantially the same common focal point, said light source located at least three times as far from the front opening of said reflector as from the vertex of said primary reflective surface so that substantially more than half of the total light is reflected by the reflector, and a lens positioned over the front of said reflector and contoured at least near the outer edge thereof to refract in a more frontwardly direction at least some of the unreflected divergent light from said light source.
9. A reflector lamp as claimed in claim 8 wherein said lens contour comprises concentric prisms.
10. A reflector lamp as claimed in claim 9 wherein said concentric prisms are on the inner surface of said lens.
11. A reflector lamp as claimed in claim 8 wherein said reflector is dimensioned so that substantially all light rays from said light source which are reflected by said spherical intermediate section axe re-reflected by said parabolic front section.
12. A reflector lamp as claimed in claim 8 wherein substantially an entire surface of said lens is contoured to refract light more inwardly, whereby light reflected by said reflector is converged into a crossover pattern and thereafter diverges to provide a floodlight pattern in cooperation with said refracted unreflected light.
13. A reflector lamp as claimed in claim 12 wherein said lens contour comprises concentric prisms.
14. A reflector lamp as claimed in claim 13 wherein said concentric prisms are on the inner surface of said lens.
15. A reflector lamp as claimed in claim 12 wherein said reflector is dimensioned so that substantially all light rays from said light source which are reflected by said spherical intermediate section are re-reflected by said parabolic front section.
16. A reflector lamp comprising a finite light source positioned substantially at the focal point of a reflector, said reflector having a substantially parabolic front section as said primary reflective surface, a substantially spherical intermediate section, and a sub-stantially parabolic rear section, each of said sections having substantially the same common focal point, said light source located at least three times as far from the front opening of the reflector as from the vertex of said primary reflective surface so that substantially more than half of the total light from said light source is reflected frontwardly by said reflector, and substantially less than half of the total light emerges at the reflector front opening unreflected and in the form of a divergent cone of light, and a lens positioned over the front of said reflector and contoured to refract substantially all of said light in a more inwardly direction whereby said unreflected light remains divergent and said reflected light is converged into a crossover pattern and thereafter diverges to provide a floodlight pattern in cooperation with said refracted, unreflected light.
17. A reflector lamp as claimed in claim 16 wherein said lens causes the divergent angles of said reflected light after crossover to be approximately the same as the divergent angles of said unreflected light in the projected light pattern.
18. A reflector lamp as claimed in claim 16 wherein said reflector is dimensioned so that substantially all light rays from said light source which are reflected by said spherical intermediate section are re-reflected by said parabolic front section.
19. A reflector lamp as claimed in claim 16 wherein said lens contour comprises concentric prisms.
20. A reflector as claimed in claim 19 wherein said concentric prisms are on the inner surface of said lens.
21. A reflector lamp as claimed in claim 8 or 16, wherein said finite light source lies substantially in a plane perpendicular to the lamp axis and intersects said focal point.
22. A reflector lamp as claimed in claim 8 or 16, wherein said finite light source lies substantially in a plane perpendicular to the lamp axis; said plane located at a distance from said focal point which is not greater than ten times the maximum light source dimension which is perpendicular to the light source major axis.
23. A reflector lamp as claimed in claim 8 or 16, wherein said finite light source lies substantially in a plane which includes the lamp axis and said focal point.
24. A reflector lamp as claimed in claim 8 or 16, wherein said finite light source lies substantially in a plane parallel to the lamp axis; said plane positioned at a distance from said focal point which is not greater than ten times the maximum light source dimension which is perpendicular to the light source major axis.
25. A reflector lamp as claimed in claim 11, 15 or 18 wherein said focal point of said spherical section is located between said common focal points of said parabolic sections and a point spaced therefrom located not greater than ten times the maximum light source dimension which is perpendicular to the light source major axis.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US21893280A | 1980-12-22 | 1980-12-22 | |
| US218,932 | 1980-12-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1197496A true CA1197496A (en) | 1985-12-03 |
Family
ID=22817076
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000392739A Expired CA1197496A (en) | 1980-12-22 | 1981-12-18 | Reflector lamp with shaped reflector and lens |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS57130367A (en) |
| CA (1) | CA1197496A (en) |
| DE (1) | DE3150195A1 (en) |
| FR (1) | FR2496841A1 (en) |
| GB (1) | GB2089956B (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57165952A (en) * | 1981-04-07 | 1982-10-13 | Tokyo Shibaura Electric Co | Light emitting sealed beam bulb |
| HU191446B (en) * | 1984-09-21 | 1987-02-27 | Tungsram Rt,Hu | Reflector lamp |
| DE3633976A1 (en) * | 1986-04-09 | 1987-10-29 | Wila Leuchten Gmbh | Ceiling spotlight with brightening of the surrounding field |
| US5128848A (en) * | 1989-03-31 | 1992-07-07 | W.C. Heraeus Gmbh | Operating light |
| DE4417884A1 (en) * | 1994-05-21 | 1995-01-05 | Braun Uwe Peter Dipl Ing | Lighting unit (lamp) for inspection of coatings |
| FR2769993B1 (en) * | 1997-10-20 | 1999-12-31 | Axo Scintex Cie Equip Automobi | CONCENTRATED REFLECTOR |
| US7918583B2 (en) * | 2006-08-16 | 2011-04-05 | Rpc Photonics, Inc. | Illumination devices |
| CN102812290B (en) * | 2010-04-09 | 2016-08-03 | 皇家飞利浦电子股份有限公司 | There is the luminaire of smooth cut-off |
| DE102011013370A1 (en) * | 2011-03-09 | 2012-09-13 | Osram Opto Semiconductors Gmbh | Optoelectronic semiconductor device |
| RU2594970C2 (en) * | 2011-05-31 | 2016-08-20 | Конинклейке Филипс Н.В. | Led-based light device with textured lenses |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB460122A (en) * | 1936-06-24 | 1937-01-21 | Friedrich Richard Dietrich | Improvements in lamp reflectors |
| JPS4020132Y1 (en) * | 1964-04-15 | 1965-07-13 | ||
| JPS422233Y1 (en) * | 1964-10-02 | 1967-02-09 | ||
| GB1270560A (en) * | 1969-07-16 | 1972-04-12 | Int Standard Electric Corp | Searchlight apparatus |
| CS188521B1 (en) * | 1976-09-01 | 1979-03-30 | Milan Cejnek | Headlight for motor vehicles |
| GB2079435B (en) * | 1980-07-03 | 1984-05-23 | Gen Electric | Reflector lamp |
-
1981
- 1981-11-30 GB GB8136112A patent/GB2089956B/en not_active Expired
- 1981-12-18 CA CA000392739A patent/CA1197496A/en not_active Expired
- 1981-12-18 DE DE19813150195 patent/DE3150195A1/en not_active Withdrawn
- 1981-12-21 JP JP56205375A patent/JPS57130367A/en active Pending
- 1981-12-22 FR FR8123918A patent/FR2496841A1/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| GB2089956B (en) | 1984-07-04 |
| FR2496841A1 (en) | 1982-06-25 |
| DE3150195A1 (en) | 1982-07-15 |
| JPS57130367A (en) | 1982-08-12 |
| GB2089956A (en) | 1982-06-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |