United States Patent [19]
`Makita et al.
`
`[11] Patent Number:
`[45] Date of Patent:
`
`4,949,226
`Aug. 14, 1990
`
`[54] PROJECfOR-TYPE LIGHTING DEVICE OF
`EXPANDED OUTLINE APPEARANCE FOR
`USE AS A VEIDCULAR HEADLAMP OR
`THE LIKE
`
`[75]
`
`Inventors: Hiroyuki Makita; Takahisa Shinoda;
`Y asuaki Nakamura; Osamu Endoh,
`all of Shizuoka, Japan
`[73] Assignee: Koito Seisakusko Co., Ltd., Tokyo,
`Japan
`[21] Appl. No.: 369,995
`[22] Filed:
`Jun.23, 1989
`Foreign Application Priority Data
`[30]
`Jun. 24, 1988 [JP]
`Japan ............................. 63-83475[U]
`Jan. 17, 1989 [JP]
`Japan ...................................... 1-5969
`Jan. 19, 1989 [JP]
`Japan .................................... 1-10495
`Int. Cl.s ............................................... B60Q 1/00
`[51]
`[52] u.s. Cl •........................................ 362/61; 362/80;
`362/247
`[58] Field of Search ................... 362/61, 80, 240, 241,
`362/247
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`4,503,488 3/1985 Soules ................................. 362/247
`4,680,680 2/1987 Iwaki ..................................... 362/80
`4,814,950 3/1989 Nakata .................................. 362/61
`4,849,861 7/1989 Arima ................................... 362/61
`4,895,693 1/1990 Suzuki et al ..
`
`FOREIGN PATENT DOCUMENTS
`2612854 9/1988 France ................................ 362/267
`5880 1/1978 Japan ................................... 362/297
`
`Primary Examiner-Douglas Hart
`Attorney, Agent, or Firm-Browdy and Neimark
`ABSTRACf
`[57]
`A vehicle headlamp having a projector-type light
`source assembly capable of emitting a highly coherent
`light beam. In order to make the headlamp appear
`larger than the light source assembly, a lamp housing is
`provided which is much larger in size than the light
`source assembly mounted therein, with the consequent
`provision of an annular space around the light source
`assembly within the lamp housing. Disposed in this
`annular space is an outline expander plate of transparent
`material having a multiplicity of minute cavities of cone
`shape formed in its rear face. The outline expander plate
`transmits by internal total reflection the light incident
`edgewise thereon. While so traveling through the out(cid:173)
`line expander plate, the light is reflected by the surfaces
`of the conical cavities generally in the forward direc(cid:173)
`tion of the headlamp, thereby making the complete
`surface area of the headlamp appear glowing. The light
`needed for illuminating the outline expander plate may
`be supplied either by the projector-type light source
`assembly or by separate light sources.
`
`15 Claims, 11 Drawing Sheets
`
`12
`
`TOYOTA EXHIBIT 1009
`
`Page 1 of 18
`
`

`

`U.S. Patent
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`Aug.14, 1990
`
`Sheet 1 of11
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`US. Patent
`Aug. 14, 1990
`U.S. Patent Aug.14, 1990
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`Sheet 2 of 11
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`4,949,226
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`U.S. Patent Aug. 14, 1990
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`Sheet 4 of11
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`Page 6 of 18
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`U.S. Patent Aug.t4, 1990
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`Sheet 6 ofll
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`4,949,226
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`Page 8 of 18
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`U.S. Patent
`
`Aug. 14, 1990
`
`Sheet 8 of11
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`4,949,226
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`FIG.8
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`Page 9 of 18
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`U.S. Patent
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`Aug. 14,.1990
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`

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`US. Patent
`Aug. 14,1990
`U.S. Patent Aug.14, 1990
`
`Sheet 10 $1 11
`Sheet 10 of 11
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`4,949,226
`4,949,226
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`FIG. 10
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`Aug. 14, 1990
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`

`

`1
`
`4,949,226
`
`PROJECI'OR-TYPE LIGHTING DEVICE OF
`EXPANDED OUTLINE APPEARANCE FOR USE
`AS A VEHICULAR HEADLAMP OR THE LIKE
`
`2
`point intermediate the projection lens and the light
`source for projecting a light beam through the lamp
`housing. The projector-type light source means is so
`small in comparison with the lamp housing that an an-
`5 nular space is left around the light source means within
`BACKGROUND OF THE INVENTION
`the lamp housing. The lighting device further comprises
`outline expansion means disposed in the annular space
`This invention relates generally to lighting devices,
`between the projector-type light source means and the
`and particularly to a projector-type lighting device
`lamp housing. The outline expansion means is capable
`suitable for use as a vehicular headlamp or the like.
`The projector-type headlamp has been known which 10 of self-illumination in order to make the lighting device
`comprises a light bulb and a reflector for reflecting and
`appear larger than when only the projector-type light
`source means is glowing.
`converging the light from the bulb. Also included is a
`In one preferred embodiment of the invention, the
`plano-convex projection lens having a focus in the vi-
`cinity of a point or line of convergence of the reflected
`outline expansion means comprises an outline expander
`light. When the light bulb is lit up, the headlamp 15 plate of transparent material, such as a plastic, which is
`projects a coherent light beam of very sharply delin-
`centrally apertured to permit the passage of the light
`eated outline. The projector-type lamp is well suited for
`beam emitted by the projector-type light source means.
`vehicular headlamp applications by virtue of its capabil-
`The outline expander plate is molded integral with a
`ity of meeting the most stringent beam pattern stan-
`multiplicity of conical cavities formed in its rear face for
`20 reflecting light incident edgewise thereon. This light for
`dards.
`.
`.
`.
`.
`A drawback has eXISted wtth the pnor art J?rOJector-
`illuminating the outline expander plate may be supplied
`~ headl~p, however. !he current tren? m the. de-
`as by a pair of light bulbs positioned opposite a pair of
`stgn of vehicle h~amps 1~ tow~d ~arger siZe~ partt~u-
`opposite edges of the outline expander plate.
`·
`larly a_great~r ho~ontal dimens~on m ~ompanson wtth
`The pair of light bulbs may be lit up at dusk or in the
`~ vertical dtmen~ton. Automobile designers have o~- 25 nighttime. Diffusely traveling through the outline ex-
`Jected to the projector-type headlamp by r~aso_ns of Its
`pander plate by internal total reflection, the light rays
`compactness and the round_ shape of the projection lens.
`on impinging upon the surfaces of the conical cavities
`In order to overcome this weakness, It has been sug-
`h
`.
`·
`·
`t
`t
`li ht
`bl
`are t ereby reflected generally m the forward drrectton
`.
`tall
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`ted t
`ges
`o ms
`a projec or- ype g
`source assem y,
`f h
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`li h ·
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`fl
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`compn
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`es subs~ti y t e w.~ siZe o the lightmg
`lens, within a lamp housing or body of much larger size
`~evtce ap~ lummous regard~~ of wh~ther the pro-
`and esthetically appearing shape. An annular reflector is
`jector-t~ light sour~e ~eans ts ~t or unlit. Therefore,
`mounted in the space left within the lamp housing by
`when a parr of such l~ghtmg de~ces m:e used as head-
`the light source assembly. The light source assembly
`projects a light beam through the central aperture in the 35 lamps _on a _motor vehicle, there ~ practically no danger
`of therr ~mg erroneously percetved ~ the he~~ps
`annular reflector in the nighttime. In the daytime, as the
`reflector reflects the daylight, the headlamp appears
`of t~o dtfferent motorcycles or the like travelmg stde
`much larger than the projector-type light source assem-
`by stde.
`.
`.
`.
`.
`~ an alternative embodtment of. the m~entton, the
`bly, the latter being practically invisible.
`This known solution is objectionable because the 40 outline expan~er. pl~te has no dedt~ated hght ~ou~ce
`reflector is mostly invisible in the nighttime. Only the
`means but has 1_ts mstde edg~ held agamst the projectiOn
`lens. of the projector-type -~ght source means: Thus ~he
`projector-type light source assembly appears bright.
`Consequently, as the car with a pair of such headlamps
`out~me expander pla~e utilizes p~ of the hght bemg
`travels, it may hallucinate the pedestrians and the driv-
`projected by the proJector-type hght source means for
`ers of the meeting and preceding vehicles into the 45 self-illumination. This scheme is preferred because of
`the simpler c~>nstruction.
`wrong perception that two motorcycles are running
`.
`.
`.
`side by side. The wrong perception may invite wrong
`The mvent10n also teaches to provtde a half-sdverei:l
`traffic decisions by the pedestrians and the drivers,
`mirror within the lamp housing and forwardly of the
`possibly resulting in traffic accidents in the worst case.
`outline expansion means. The half-silvered mirror
`so glows by being illuminated by the outline expansion
`means in the nighttime, and by reflecting daylight in the
`daytime.
`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 at(cid:173)
`tached drawings showing the preferred embodiments of
`the invention.
`
`SUMMARY OF THE INVENTION
`The present invention defeats the noted difficulties
`encountered with the prior art projector-type lighting
`device particularly when it is used as a vehicular head(cid:173)
`lamp or for similar applications. More specifically, the 55
`invention provides an improved projector-type lighting
`device that appears much larger in size, or in more
`esthetically favorable shape, than the projection lens in
`use.
`Briefly, the improved projector-type lighting device 60
`of the invention may be summarized as comprising
`projector-type light source means disposed at least in
`part within a lamp housing of desired shape and size
`approximately in a central position on the latter. The
`projector-type light source means comprises a light 65
`source, a reflector for reflecting and converging the
`light from the light source, and a projection lens dis(cid:173)
`po~d opposite the light source and having a focus at a
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a front elevation of projector-type vehicle
`headlamp to which the present invention fmds applica(cid:173)
`tion;
`FIG. 2 is a vertical section through the headlamp of
`FIG. 1, taken along the line 11-11 therein;
`FIG. 3 is a horizontal section through the headlamp
`of FIG. 1, taken along the line III-III therein;
`
`Page 13 of 18
`
`

`

`4,949,226
`
`4
`14. The open front side of the lamp body 18 is closed by
`a front cover or control lens 21 of vitreous material.
`
`3
`FIG. 4 is a enlarged, schematic perspective view of
`the projector-type light source assembly used in the
`headlamp of FIG. 1;
`Projector-Type Light Source Assembly
`FIG. 5 is an enlarged, fragmentary horizontal section
`through the headlamp of FIG. 1, also taken along the S
`The projector-type light source assembly 14 appears
`in FIGS. 2 and 3 and in greater detail in FIG. 4. It
`line 11-11 therein and showing the outline expansion
`comprises a light source shown as a bulb 22, a reflector
`means in more detail for the discussion of its operation;
`24 having the bulb mounted centrally therein for re-
`FIG. 6 is a view similar to FIG. 2 but showing an-
`fleeting and converging the light emitted by the bulb 23,
`other preferred form of projector-type headlamp ac-
`10 and a plano-convex projection lens 26 disposed for-
`cording to the invention;
`wardly of the reflector for projecting the reflected light
`FIG. 7 is a horizontal section through the headlamp
`fi
`1
`dl thr
`th
`f
`of FIG. 6;
`orwar y
`ough e contra lens 2 o the lamp hous-
`FIG. 8 is also a view similar to FIG. 2 but showing
`ing U.
`still another preferred form of projector-type headlamp
`The light bulb 22 has an envelop 28 of suitable high-
`according to the invention;
`temperature vitreous material containing a filament 30.
`FIG. 9 is a front elevation of a further preferred form
`This filament is disposed at ~he focus F of the reflector
`of projector-type headlamp according to the invention;
`24 .. The r~flector f?Cus F will be def~ed subsequently.
`FIG. 10 is a vertical section through the headlamp of
`A light shield coating 32 at the front tip of the envelop
`FIG. 9, taken along the line X-X therein; and
`FIG. 11 is a horizontal section through the headlamp 20 28 serves to shield the light rays from the filament 30
`of FIG. 9, taken along the line XI-XI therein.
`against direct forward irradiation.
`The reflector 24, with a reflective surface 34, is herein
`shown as being of the combined paraboloidal-elliptical
`type. By the paraboloidal-elliptical reflector is meant
`25 the reflector that is paraboloidal in horizontal section as
`in FIG. 3 and elliptic in vertical section as in FIG. 2.
`Further the focus of the paraboloid and the frrst focus of
`the ellipse are at the same point F on a common optical
`axis x-x. This common point is hereby defmed as the
`aforesaid focus F of the reflector 24.
`Accordingly, with the filament 30 of the light bulb 22
`positioned at the reflector focus F, the light rays R
`emitted by the light bulb become parallel to the optical
`axis x-x in a horizontal direction on reflection from the
`reflector 24, as illustrated in FIG. 3. In a vertical direc(cid:173)
`tion, on the other hand, the light rays R converge at the
`second focus of the ellipse in which the reflector 24 is
`shaped vertically, as indicated in FIG. 2. Consequently,
`as will be understood from FIG. 4, the light rays R
`converge at and along a horizontal line F that right(cid:173)
`angularly crosses the optical axis x-x at the second
`focus of the ellipse. It will therefore be seen that, taken
`in a vertical plane at right angles with the optical axis
`x-x and just forwardly or rearwardly of the line of
`convergence F, the beam of reflected light rays R has a
`horizontally elongated, rectangular shape, as indicated
`by the hatching and designated Fin FIG. 4.
`Despite the showings of FIGS. 2-4, it is not desired
`that the reflector 24 of the projector-type light source
`assembly 14 be limited to the combined paraboloidal(cid:173)
`elliptic configuration. Any other suitable type of reflec(cid:173)
`tor may be employed depending upon the desired beam
`pattern. Examples are a paraboloid of revolution and a
`deformed ellipse.
`The projection lens 26 of the projector-type light
`source assembly 14 takes the form of a plano-convex
`lens, with the convex side directed forwardly of the
`headlamp 10. Positioned forwardly of the reflector 24,
`the projection lens 26 has a focus Pc somewhat rear(cid:173)
`wardly of the line of convergence F of the reflector.
`Therefore, the projection lens 26 throws the reflected
`light rays R forwardly of the headlamp 10 with the
`beam pattern P inverted. A lens holder tube 36 is se(cid:173)
`cured endwise to the periphery of the reflector 24 and
`firmly holds the projection lens 26 on the other end.
`Thus the projection lens 26 is supported in position with
`respect to the reflector 24.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`General
`The invention will now be described more specifi(cid:173)
`cally as embodied in the vehicle headlamp generally
`designated 10 in FIGS. 1-3. The exemplified headlamp
`10 has a lamp housing U of generally rectangular shape
`as seen in a front view as in FIG. 1. Mounted to the 30
`lamp housing 12 in a central position thereon and partly
`received therein is a projector-type light source assem(cid:173)
`bly 14, FIGS. 2 and 3, for emitting a light beam of
`desired pattern. It will be seen that the projector-type
`light source assembly 14 is much less in size, both verti- 35
`cally as seen in FIG. 2 and horizontally as in FIG. 3,
`than the lamp housing U. An annular space is therefore
`left around the projector-type light source assembly 14
`within the lamp housing U.
`FIGS. 2 and 3 also reveal outline expansion means 16 40
`disposed in the annular space between the lamp housing
`U and the projector-type light source assembly 14 in
`accordance with a feature of the invention. The outline
`expansion means 16 are capable of self-illumination. The
`size and shape of the outline expansion means 16 as seen 45
`in a front view approximately correspond to those of
`the lamp housing U. Therefore, when the outline ex(cid:173)
`pansion means 16 are glowing, either by self-illumina(cid:173)
`tion or by reflection of the daylight, the headlamp 10
`appears luminous substantially throughout its full verti- 50
`cal and horizontal dimensions.
`The following is a more detailed discussion of the
`lamp housing U, the projector-type light source assem(cid:173)
`bly 14, and the outline expansion means 16, in that order
`and under separate headings. The description of opera- 55
`tion and advantages will follow the discussion of the
`listed headlamp components.
`
`15
`
`Lamp Housing
`As will be understood from FIGS. 1-3, the lamp 60
`housing 12 has a lamp body 18 of rigid plastic or like
`material and of generally rectangular, horizontally elon(cid:173)
`gated shape as seen in a front view as in FIG. 1. The
`lamp body 18 has a closed rear side, shown directed to
`the right in FIG. 2, and an open front side. The rear side 65
`of the lamp body 18 is formed to include a rearward
`protuberance or recess 20 positioned centrally thereon
`for mounting the projector-type light source assembly
`
`Page 14 of 18
`
`

`

`4,949,226
`
`6
`Thus, with the complete outline expander plate 38
`glowing, substantially the full horizontal and vertical
`dimensions of the headlamp 10 will become visible to
`the pedestrians and the drivers of the meeting or pre(cid:173)
`ceding vehicles, even though it is only the projector(cid:173)
`type light source assembly 14 of far smaller size that is
`throwing a light beam for road illumination. The pedes(cid:173)
`trians and drivers will readily recognize the headlamp
`10 as being that of a four-wheeled motor vehicle rather
`than of a two-wheeled vehicle.
`Even when the light bulbs 48 are unlit as at dusk, the
`outline expander plate 38 will glow when irradiated as
`by the headlamp beams of approaching vehicles. The
`headlamp 10 will then be more readily recognized as
`such.
`Optionally, the filter plate 56 may be employed to
`make the outline expander plate 38 to glow in any color
`chosen from utilitarian or esthetic considerations. It
`may also be contemplated to make variable the intensity
`of illumination of the outline expander plate 38.
`It is to be understood that the conical cavities 40 in
`the outline expander plate 38 do not represent the sole
`means of reflecting the light from the bulbs 48. Such
`cavities may be replaced by grooves, by a reflective fllm
`or layer, or by any means capable of similarly reflecting
`light from its source or sources apart from the projec(cid:173)
`tor-type light source assembly 14.
`
`5
`Outline Expansion Means
`As illustrated in FIGS. 2 and 3 and on an enlarged
`scale in FIG. 5, the outline expansion means 16 include
`an outline expander plate 38 of transparent material, 5
`typically a plastic, complete with a multiplicity of coni(cid:173)
`cal cavities 40 forced in its rear face directed away from
`the control lens 21. The outline expander plate 38 is
`shaped and sized to substantially completely close the
`front opening 42 of the lamp body 18. A central aper- 10
`ture 44 in the outline expander plate 38 receives part of
`the projection lens 26 of the light source assembly 14
`with clearance, permitting the same to project the light
`beam through the aperture.
`FIGS. 3 and 5 show a pair of opposite edges 46 of the 15
`outline expander plate 36 in a horizontal direction. Dis(cid:173)
`posed opposite these edges 46 of the outline expander
`plate 38 are a pair of light bulbs 48 for irradiating the
`same. The light rays from the bulbs 48 are reflected by
`the surfaces of the conical cavities 40 in the outline 20
`expander plate 38 and thereby to be thrown generally
`forwardly of the headlamp 10, as indicated at R in
`FIGS. 3 and 5.
`The outline expander plate 38 is supported by a gen(cid:173)
`erally flat holder 50 secured to the lamp body 18. This 25
`holder 50 is also centrally apertured at 51, in register
`with the aperture 44 in the outline expander plate 38 for
`exposing the projector-type light source assembly 14.
`As an incidental feature of the invention, a diffuser
`plate 52 is disposed forwardly of the outline expander 30
`plate 38 with a view to. the uniformity of the light re(cid:173)
`flected by the outline expander plate. The diffuser plate
`52 is also centrally apertured at 54 for exposing the
`projector-type light source assembly 14.
`Seen at 56 in FIGS. 2, 3 and 5 is a filter plate consti- 35
`tuting another optional feature of the invention. The
`filter plate 56 closes the complete front opening 42 of
`the lamp body 18. The fllter plate 56 may be suitably
`colored. For example, it may be colored yellow for use
`of this lighting device as a fog lamp. Alternatively, the 40
`central portion of the fllter plate 56 may be colorless
`and transparent, and the remaining portion may be col(cid:173)
`ored. A metallic color may also be employed. When the
`light bulbs 48 of the outline expansion means 16 are lit
`up at dusk, the complete surface of the front lens 21 will 45
`give off a dim light, making the lamp very attractive
`esthetically.
`An additional possible modification of the headlamp
`10 is the provision of a half-silvered mirror fllm on the
`front lens 21. Such a mirror may be employed either in 50
`substitution for, or in combination with, the fllter plate
`56.
`
`Second Form
`FIGS. 6 and 7 show a second preferred form of head(cid:173)
`lamp according to the invention. The various parts of
`this alternative headlamp will be indicated by the same
`reference numerals as used to denote the corresponding
`parts of the FIGS. 1-5 headlamp 10, only with the digit
`"1" prefixed to such numerals.
`The second headlamp 110 features modified outline
`expansion means 116 which differs from the outline
`expansion means 16 of the FIGS. 1-5 headlamp 10 in
`having no devoted light source means. Instead, the
`outline expansion means 116 utilizes the light emitted by
`a projector-type light source assembly 114 for self(cid:173)
`illumination.
`The primary component of the outline expansion
`means 116 is an outline expander plate 138 shaped and
`sized to conform to the shape and size of the front open(cid:173)
`ing 142 of a lamp body 118. The lamp body 118 makes
`up a lamp housing 112 in combination with a front
`cover or control lens 121. The outline expander plate
`138 is mounted in position by having its periphery se(cid:173)
`cured to the front inside edge of the lamp body 118,
`instead of by being supported by the holder 50 as in the
`preceding embodiment. Also, in this alternative em(cid:173)
`bodiment, the outline expander plate 138 is not exactly
`planar but is slightly convexed rearwardly.
`Operation
`The pair of light bulbs 48 of the outline expansion 55 An aperture 144 of circular shape is defmed centrally
`in the outline expander plate 138. The inside edge of the
`means 16 may be lit up together with the bulb 22 of the
`projector-type light source assembly 14 at dusk or in the
`outline expander plate 138, bounding the aperture 144,
`nighttime. The light rays from the bulbs 48 will enter
`is held opposite a peripheral part of the front, convex
`the outline expander plate 38 through its opposite edges
`side of a plano-convex projection lens 126 of the projec-
`46 and travel throughout the plate by internal total 60 tor-type light source assembly 114. Thus the light re-
`quired for illuminating the outline expander plate 138 is
`reflection, as indicated by the arrow headed lines desig-
`nated R in FIGS. 3 and 5. While so traveling through
`supplied by the projector-type light source assembly
`the outline expander plate 38, the light rays R will
`114. The outline expander plate 138 has a multiplicity of
`partly impinge on the surfaces of the conical cavities 40
`conical cavities 140 formed in its rear face for reflecting
`in its rear face. The light rays R will be reflected by 65 the light from the light source assembly 114.
`As required or desired, the noted peripheral port of
`such surfaces generally forwardly of the headlamp 10
`through the diffuser plate 52, filter plate 56 and front
`the convex side of the projection lens 126 may be suit-
`cover or lens 21.
`ably knurled in order that a greater amount of light may
`
`Page 15 of 18
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`

`4,949,226
`
`8
`this lighting device 210 are identical with those of the
`FIG. 6 and 7 device 110.
`
`7
`be supplied to the outline expander plate 138. Also, the
`surface of the inside edge of the outline expander plate
`138 may be either concaved or laid normal to the travel(cid:173)
`Operation of Third Form
`ing direction of the light issuing from the peripheral
`part of the convex side of projection lens U6, in order 5 With the second filament 270 disposed below the
`to better receive the light from the projection lens.
`focus F of the reflector 224, the light rays R emitted
`Preferably, and as shown, a half-silvered mirror 160 is
`thereby are hardly cut off by the shield screen 266.
`mounted within the lamp housing 1U just forwardly of
`Therefore, despite the reduced intensity of the light
`the outline expander plate 138. The half-silvered mirror
`emitted by the second filament 270 itself, a sufficient
`160 comprises a flat carrier plate 162 of transparent 10 amount of light is supplied from the peripheral part of
`material carrying a metallic film 164 on its front face.
`the projection lens 226 to the outline expander plate
`The metallic film 164 has a thickness such that approxi-
`238, causing the latter to flow uniformly throughout its
`entire area. The uniformly glowing outline expander
`mately half the light falling thereon at normal incidence
`is reflected, the other half being transmitted.
`plate 238 makes it possible for this lighting device 210 to
`The projector-type light source assembly 114 is also 15 perform the additional functing of clearance lamp. Of
`slightly different in construction from its counterpart of
`course, the device 210 functions as headlamp when the
`the FIGS. 1-5 headlamp 10. The difference consists
`first filament 230 is switched on.
`principally in a shield screen 166 rigidly supported up(cid:173)
`Fourth Form
`standingly within a lens holder tube 136. With its top
`edge 168 disposed at the focus Pc of the projection lens 20
`FIGS. 9-11 illustrate a further preferred form of
`headlamp 310 featuring modified outline expansion
`126, the shield screen 166 functions to cut off the bot-
`means 316. The outline expansion means 316 comprises
`tom half of the beam being converged by the reflector
`a pair of outline expansion light source assemblies 372
`124. Since the beam pattern is subsequently inverted by
`juxtaposed horizontally on both sides of a projector-
`the projection lens U6, the beam of light projected by
`this headlamp 110 is virtually free from the unnecessary 25 type light source assembly 314 within a lamp housing
`upward component.
`3U, and a half-silvered mirror 360 positioned in front of
`The headlamp 110 is analogous with the FIGS. 1-5
`the outline expansion light source assemblies 372 and
`headlamp 10 in the other details of construction.
`closing the front opening 342 of the mirror body 318.
`The projector-type light source assembly 314 is shown
`Operation of Second Form
`30 to be of the same construction as its counterpart 114 of
`the FIGS. 6 and 7 headlamp 110.
`The headlamp 110 conventionally projects a beam of
`The pair of outline expansion light source assemblies
`light R when the bulb U2 of the projector-type light
`source assembly 114 is lit up. The outline expansion
`372 are alike in construction each comprising a light
`means 116 of this embodiment is based on the fact that
`bulb 374 and a generally concave reflector 376 having
`the projection lens U6 emits a substantial amount of 35 the bulb 374 mounted centrally thereto.
`light more or less in its lateral direction. This lateral
`The half-silvered mirror 360 can also be of the same
`component of the light beam is utilized for illuminating
`construction as its counterpart 160 of the FIGS. 6 and 7
`the outline expander plate 138. As such lateral light
`headlamp 110. Thus the half-silvered mirror 360 com-
`component enters the outline expander plate 138 from
`prises a carrier plate 362 of a transparent plastic or like
`its inside edge and travels therethrough by internal total 40 material, and a metallic film 364 on the front face of the
`reflection, the surfaces of the conical cavities 140 in its
`carrier plate 362. Unlike the half-silvered mirror 160 of
`rear face reflect the light generally forwardly of the
`the FIGS. 6 and 7 headlamp 110, this half-silvered mir-
`headlamp 110, as indicated at R. Thus, as the outline
`ror 360 is shown to be centrally apertured at 378 to
`expander plate 138 glows, the complete area of the
`expose the projection lens 326 of the projector-type
`headlamp 110 appears glowing.
`45 light source assembly 314.
`In the daytime, too, the half-silvered mirror 160 will
`The headlamp 310 is akin to the foregoing embodi-
`reflect the daylight, so that the complete area of the
`ments in the other details of construction.
`headlamp 110 will appear glowing. A similar half-sil(cid:173)
`vered mirror could of course be employed in the FIGS.
`1-5 headlamp 10.
`
`50
`
`Third Form
`The headlamp 210 shown in FIG. 8 represents an
`adaptation of the FIGS. 6 and 7 headlamp 110 for use as
`clearance lamp as well. The headlamp 210 features an 55
`electric bulb 222, included in a projector-type light
`source assembly 214, that has a second fllament 270 in
`addition to the first filament 230 corresponding to the
`fllament 30 of the FIGS. 1-5 headlamp 10. The second
`filament 270 is to glow in use of the headlamp 210 as 60
`clearance lamp, so that the intensity of the light pro(cid:173)
`duced by this second filament can be considerably less
`than that emitted by the first filament 230.
`An inspection of FIG. 8 will also reveal that the
`second filament 270 is disposed below the focus F of the 65
`reflector 224 of the light source assembly 214. The first
`filament 230 is at the reflector focus F as in the forego(cid:173)
`ing embodiments. The other details of construction of
`
`Operation of Fourth Form
`The bulbs 374 of the pair of outline expansion light
`source assemblies 372 may be lit up together with the
`bulb 322 of the projector-type light source assembly 314
`during night driving. The light rays direct from the