Visual signaling apparatus

Abstract: A visual signaling apparatus including an enclosure 50 having an aperture 61, and defining a cavity 60, a light source 70 for emitting light in predetermined wavelengths borne by the enclosure 50 and positioned in the cavity 60; and a semi-transparent dichroic mirror 110 borne by the enclosure 50 and disposed in substantially occluding relation relative to the aperture 61, the semi-transparent dichroic mirror 110 being adapted to selectively reflect ambient light and to transmit the predetermined wavelengths of light emitted by the light source 70.

Description: The invention relates to a combined mirror and visual signaling apparatus comprising a housing with an aperture, a semi-transparent mirror substantially occluding the aperture, a light source mounted inside the housing, and a baffling assembly between the light source and the mirror, the baffling assembly having louvers which direct the light from the light source into a predetermined direction and which substantially inhibits the light from emanating in directions other than the predetermined direction. Such apparatus is known from GB-A-1.172.382 or AU-A-11.419/66. Combined signaling apparatus of the type referred to are used as outer rear mirrors for motor vehicles simultaneously used to signal intended turns or lane changes to the surrounding traffic and may be used as additional, "third" brake signal when used as interior mirror in an automobile. In the prior art combined mirror and visual signaling apparatus known from the above-referenced documents, the semi-transparent mirrors are neutral ones such as half-silver mirrors which do not have an average transmittance or an average visible spectrum reflectance which permit them to simultaneously be an excellent reflector and an excellent transmitter of light. It is accordingly an object underlying the invention to provide for a combined mirror and visual signaling apparatus which provides both a satisfactory view rearwards from an operators position and a satisfactory signaling effect to other traffic participants. According to the present invention this object is solved in that the mirror consists of a dichroic mirror. With such arrangement it is possible to adjust the characteristic of the light generated by the light source to the reflectance and transmittance characteristics of the dichroic mirror or, vice versa, so that satisfactory results are obtained in both respects. Preferred further developments and embodiments of the present invention are described in the sub-claims, the purposes and advantages whereof will become apparent from the further description. The invention will be further described with reference to the preferred embodiment shown in the drawings, in which: Fig. 1 is a plan view of the apparatus of the subject invention shown in an operative environment of an overland vehicle and wherein some underlying surfaces are illustrated in phantom lines for illustrative convenience. Fig. 1A is a schematic plan view of the apparatus of the subject invention shown in an operative environment, and wherein the surrounding supporting surfaces are removed for illustrative convenience. Fig. 2 is a perspective, exploded, side elevation view of the apparatus of the subject invention taken from a position along line 2-2 of Fig. 1. Fig. 3 is an enlarged, side elevation view of the light control film utilized in connection with the apparatus of the subject invention. Fig. 4 is a graphic illustration of the viewing angle, in degrees, as it relates to the percentage of transmission of the light control film shown in Fig. 3. Fig. 5 is a graphic illustration of the reflectance and transmittance of a neutral, semi-transparent mirror, such as a half-silvered mirror, and wherein the neutral, semi-transparent mirror has an average transmittance of approximately 58% and an average visible spectrum reflectance of 37%. Fig. 6 is a graphic illustration or the reflectance and transmittance of a neutral, semi-transparent mirror such as a half-silvered mirror, and wherein the average visible spectrum reflectance is approximately 75% and the average transmittance of light having wavelengths in the 600 through 700 nanometer band is approximately 20%. Fig. 7 is a graphic illustration of the reflectance and transmittance of the apparatus of the subject invention and wherein the apparatus includes a dichroic mirror which has an average visible spectrum reflectance of 75%, an average transmittance for light having wavelengths in the 600 through 700 nanometer band of approximately 58%, and greater than 90% transmittance for wavelengths greater than 700 nanometers. Referring more particularly to the drawings the visual signaling apparatus of the present invention is generally indicated by the numeral 10 in Fig. 1. For illustrative convenience the apparatus shown and described herein is discussed as it would be configured if it were installed on an overland vehicle 11 of conventional design and wherein the apparatus may be mounted on the vehicle, alternatively in place of the rearview mirror which is located in the passenger compartment, and/or in place of the side view mirrors which are mounted on the exterior surface of the vehicle. The apparatus 10 is adapted to operate as a combination rearview mirror and visual signaling apparatus and wherein the visual signal it provides is capable of being seen from a position rearwardly of the overland vehicle 11 but which further cannot be seen by an operator of the same vehicle. As best illustrated by reference to Fig. 1 the visual signaling apparatus 10 of the subject invention is mounted on an overland vehicle 11 of conventional design having a front end or forward portion 12 and a rear end or portion 13. The overland vehicle 11 has a passenger compartment 14 which includes a front seat 15 and which further defines an operator's position 20. The overland vehicle 11 also includes front and rear windscreens 21 and 22, respectively, and further has a longitudinal line or reference 23, a steering wheel 24 and a brake pedal 25. A pair of side view mirrors 26 are mounted on opposite sides of the overland vehicle and in a position exterior to the passenger compartment 14. The overland vehicle 11 further has a hand operated directional signaling switch 27 which is coupled with a directional signaling assembly [not shown], and which provides a visual signal which may alert drivers of other vehicles in the immediate vicinity that the overland vehicle 11 is about to change directions, turn, change lanes, etc. As best illustrated by a comparison of Figs. 1 and 1A an operator 30 when positioned in the operator's position 20 has a field of view which extends approximately 180° from the operators position toward the forward portion 12 of the vehicle. Further and by using the pair of side view mirrors 26, and the apparatus 10 the operator may, by looking along predetermined lines of sight, view areas beyond his normal field of view, and rearwardly of the operators position 20. In particular, and as best illustrated by reference to Fig. 1A, the operator 30 has a first line of sight 31, which extends from the operator 30, to the apparatus 10 and which permits the operator to view rearwardly of the vehicle 11 and substantially along the longitudinal line of reference 23. The operator 30 further has a second line of sight 32 which extends from the operator to the left or operator's side view mirror 26 of the vehicle 11 and rearwardly thereof and which permits the operator 30 to view rearwardly of the overland vehicle along a line of sight which is substantially parallel to the longitudinal line of reference 23. Furthermore, the operator has a third line of sight 33 which extends from the operators position 20 to the passengers side view mirror 26 and rearwardly thereof. It similarly permits the operator to view along a line of sight which is substantially parallel to the longitudinal line of reference 23. Each of the respective lines of sight 31, 32 and 33 have a first component 34 which extends from the operator to the respective mirror; and a second component 35 which extends rearwardly of the vehicle. Further the individual mirrors 26 and the apparatus 10 each have respective illumination zones 36. These relationships are best seen by reference to Fig. 1. The apparatus 10, and which is best illustrated by reference to Fig. 2, includes a support member 40 having first and second ends 41 and 42 respectively, and wherein the first end 41 is fixed to a mounting bracket 43 which includes a pair of apertures 44, The apertures 44 are adapted to receive suitable fasteners such as screws or the like. In addition, the second end 42 is fixed to a swivel connector 45 in a manner which is well understood in the art. The mounting bracket has a substantially centrally disposed aperture 46 which is mounted in registry with a passageway 47 which is formed substantially centrally of the support member 40. An aperture 48 is formed in the swivel connector 46 and disposed in registry with the passageway 47. The swivel connector 45 is fixed to a housing or enclosure 50 and thereby permits the enclosure to be rotated into various positions relative to the operator's position 20 thereby positioning an accompanying mirror in selected positions to provide a field of view rearwardly of the overland vehicle 11 appropriate for the operator 30. The housing 50 has a top wall 51 which has formed therein an aperture 51A which is disposed in substantial registry with the aperture 48, a bottom wall 52, and a side wall 53 which joins the top and bottom walls together. As shown in Fig. 2, the sidewall 53 is narrowly rectangular and arcuately shaped, however it should be understood that other enclosure shapes will work with equal success and the final enclosure shape will be largely determined on aesthetic considerations. The individual wall members 51, 52 and 53 respectively have exterior or outside surfaces 54 and opposite inside surfaces 55 which define a cavity 60 of predetermined dimensions. Further the individual walls, in combination, define an aperture 61 which permits access to the cavity 60. As best illustrated by reference to Fig. 2 a lighting means and which is herein illustrated as a light source which is generally indicated by the numeral 70, is borne by the housing 50 and mounted in the cavity 60 for purposes of emitting artificial light of predetermined wavelengths. Three alternative light sources are shown which may be used with equal success. However, the invention is not limited to the three light sources discussed herein but may include other artificial light sources which have the characteristics which will be discussed in greater detail hereinafter. It should be understood that notwithstanding the light source 70 selected, the light source must be operable to produce wavelengths of light which are substantially "matched", that is, having wavelengths which are substantially identical to the peak wavelength transmittance characteristics of an associated dichroic mirror 110 and which is mounted on the enclosure 50 and disposed in substantially occluding relation relative to the aperture 61. In the present form of the invention the individual light sources are operable to produce artificial light having wavelengths which include the 600 through 700 nanometer band and which manifests itself by producing the color red. The invention is not limited to the peak wavelengths recited herein and may further be used with any number of wavelength combinations such that any visual spectrum colors can be seen. The individual light sources include first, second and third forms, 71, 72, and 73, respectively. The first form 71 of the light source 70 includes a bank of LEDs [light emitting diodes]; the second form 72 of the light source 70 includes a single lamp having a light bulb and suitable reflector; and the third form 73 includes a lamp support plate which is adapted to receive a plurality of automotive light bulbs 91. The first form 71 of the light source 70 includes a bank of LEDs which are individually mounted on a support plate 74 and which are adapted to produce artificial light having wavelengths which include the 600 through 700 nanometer band. Each of the respective LEDs have a beam center 76 which is individually oriented in substantially the same direction and which, in the form of the invention shown in Fig. 2, would normally be oriented in a direction wherein the artificial light produced from the individual LEDs would travel along a transmission path 77 which is disposed in substantially parallel relation relative to the longitudinal line of reference 23 and rearwardly of the overland vehicle 11 such that it could be seen by another vehicle traveling in close proximity thereto and within the illumination zone 36. Suitable electrical leads 78 would connect the bank of LEDS with the braking or signaling assembly of the vehicle not shown. The electrical leads would extend through the passageway 47 of the support member 40 to the appropriate signaling assembly. The second form 72 of the light source 70 is best seen by reference to Fig. 2 and may be used in place of the first form of the light source 71 and which was described earlier as a bank of LEDS. With respect to the second form of the light source 72, the second form includes a single bulb or lamp 81 which is mounted in or made integral with a suitable reflector 82. The lamp would be connected by suitable electrical leads 83 to the signaling assemblies of the vehicle such as, for example the braking system and wherein upon applying pressure to the brake pedal 25 the lamp would become energized. The lamp 80 has a beam center 84 which is similar in function to the beam centers described with respect to the first form of the light 71. As best illustrated by reference to Fig. 2 the third form 73 of the light source 70 includes a synthetic lamp support plate 90 which is adapted to support a plurality of replaceable automotive bulbs or lamps 91. As best seen by reference to the drawings, the lamp support plate has a plurality of apertures 93 which permits the individual replaceable lamps to be electrically coupled to the lamp support plate. The lamp support plate, of course, carries suitable etching on the reverse surface [not shown] which conducts electric current from appropriate electric leads 94 to the individual lamps. These lamps 91 similarly produce artificial light having wavelengths which include the wavelengths of 600 through 700 nanometers. A baffling assembly, which is generally indicated by the numeral 100, includes a polycarbonate light control film which permits artificial light generated by the light source 70 to escape from the enclosure 50; the light emitted by the light source 70 traveling along the transmission path 77 and rearwardly of the overland vehicle 11 as best illustrated by reference to Fig. 1. The light control film 101 is a thin plastic film enclosing a plurality of closely spaced, black colored microlouvers. The light control film is approximately 0.75 millimeters (0.030 inches) thick, and the microlouvers are spaced approximately 0.127 millimeters (0.005 inches) apart. The microlouvers may be a transparent black or an opaque black, and further, the microlouvers may be positioned in various angles to provide a viewing angle, which may include angles as narrow as 48° ± 6° or as wide as 90° ± 15°. This is shown most clearly by reference to Fig. 4. It should be understood that the baffling assembly permits light emitted to escape within the viewing angle from the housing 50 and travel rearwardly of the vehicle 11 along the transmission path 77 and within the illumination zones, but further is operable to inhibit or block the light emitted by the light source 70 from traveling outside the viewing angle and along the first component 34 of the first line of sight 31 and into the view of the operator 30. This is best seen by reference to Figs. 1, 1A and 2. It should be apparent, therefor, that the operator may continue to use the apparatus 10 as a rearview mirror notwithstanding that artificial light is being emitted from same and is capable of being seen from a location rearwardly of the overland vehicle 11. The light control film 101 has a forward facing or front surface 102 and a back or rearward facing surface 103. Further, the light control film is defined by a peripheral edge 104, the light control film being adapted to closely fit the interior dimensions of the cavity as defined by the inside surface 55 of the walls 51, 52, and 53 respectively. As best seen by reference to Fig. 2, the apparatus 10 includes a semi-transparent mirror 110. The semi-transparent mirror is a dichroic mirror which is adapted selectively to transmit and reflect light having predetermined wavelengths. As earlierly discussed, the light source 70 is operable to produce artificial light having wavelengths of 600 through 700 nanometers which corresponds with the visible spectrum color red. In the preferred embodiment, the dichroic mirror 110 is operable to transmit the selected wavelengths of 600 through 700 nanometers thereby achieving several laudable benefits. Of course, and should a different visible color be desired, then, in that event, a different dichroic mirror would be selected which would transmit the wavelengths corresponding with the color selected. The dichroic mirror 110 has a front or forward facing surface 111, a back or rearwardly facing surface 112, and a peripheral edge 113 which closely fits the cavity 60 of the enclosure 50 thereby substantially occluding the aperture 61. This construction essentially inhibits any light leakage from the light source 70 which is mounted internally of the housing 50. To best understand the advantages achieved by employing a dichroic mirror 110 Figs. 5, 6, and 7 demonstrate that a neutral, semi-transparent half-silvered mirror will not operate effectively for purposes of the present invention in view of optical characteristics inherent in its composition and structure. More particularly, Figs. 5 and 6 show the relationship of transmittance and reflectance as it relates to neutral half-silvered mirrors. In general, as the transmittance increases reflectance decreases, and vice versa. This relationship is shown by a comparative study of Figs. 5 and 6. Referring more particularly to Fig. 5, this figure illustrates the characteristics of a neutral semi-transparent mirror which is capable of transmitting 58%, average, 600 through 700 nanometer wavelengths but is only capable of reflecting 37%, average, visible spectrum wavelengths. Similarly, and referring more particularly to Fig. 6, when a neutral transparent mirror, such as a half-silvered mirror is rendered operable to reflect 75% of the visible spectrum, the same mirror transmits only 20%, average, visible spectrum wavelengths. The relationship is clear, that is, as reflectance increases the corresponding ability of a neutral half-silvered mirror to transmit decreases, therefor in order to be a good reflector, the mirror, of necessity, must be a poor transmitter. If the mirror is a poor transmitter, then, in that event, a more powerful lamp must be utilized in order to have the same effect with respect to signaling. Utilizing a more powerful lamp, of course, creates problems in terms of the production and accumulation of heat in the enclosure 50 and the related problem of the dissipation of same. In light of the above identified problems the present invention addresses same by providing a dichroic mirror 110 which is substantially "matched" with the light source 70 and more particularly to the selected wavelengths of light produced by the light source, that is, the dichroic mirror is operable to transmit a large percentage of the selected wavelengths of artificial light while simultaneously retaining the ability to be an excellent reflector of ambient artificial and natural light. By utilizing such a "matched" dichroic mirror, and as best understood by reference to Fig. 7, the dichroic mirror remains an excellent reflector, that is, achieving an average visible spectrum reflectance of 75%, while simultaneously achieving an average transmittance in the 600 through 700 nanometer band of 58%. Thus the apparatus of the subject invention, by utilizing a dichroic mirror substantially "matched" to the wavelengths of artificial light transmitted, becomes both an excellent reflector of ambient, visible spectrum light, as well as an excellent transmitter of artificial light emitted by light source 70. Further, and by utilizing a dichroic mirror 110 which is substantially "matched" to the wavelengths of light selected, the lower intensity light source 70 may be utilized thereby alleviating the problem related to the generation of heat within the enclosure 50. The dichroic mirror also operates to transmit the longer wavelengths of artificial light which generate heat energy thereby further inhibiting the generation and accumulation of heat within the enclosure 50. The operation of the described embodiment of the present invention is believed to be readily apparent and is briefly summarized at this point. As best illustrated by reference to Fig. 2 the apparatus 10 of the present invention includes a housing 50 having a cavity 60 and defining an aperture 61 wherein the housing 50 is mounted on the overland vehicle 11 in a location within a line of sight 31, 32, and/or 33 of an operator 30 who is positioned in the operator's position 20. The apparatus 10 of the subject invention further includes a light source 70 mounted in the housing 50, and which is positioned in the cavity 60, the light source 70 electrically coupled with a signaling assembly (not shown) which in turn is coupled with a directional signaling switch 27, or a switch (not shown) which is used in combination with the brake pedal 25. As should be understood, and upon activation of the signaling assembly, the light source 70 is energized thereby producing light having wavelengths which include the 600 through 700 nanometer band. The semi-transparent dichroic mirror 110 is mounted on the enclosure 50 and is disposed in substantially occluding relation relative to the aperture 60 and which is adapted substantially to reflect 75% [average] visible spectrum wavelengths and further is operable to transmit substantially 58% [average] wavelengths having 600 to 700 nanometers. A light control film 101 having a plurality of microlouvers 105 is positioned between the dichroic mirror 110 and the light source 70 and is adapted to direct or otherwise permit the escape of light emitted by the light source 70 from the housing 50 and along the transmission path 77 which is disposed in a position which is substantially parallel to the longitudinal line of reference 23 and rearwardly of the overland vehicle 11 such that it may be seen by the operators of adjacent overland vehicles travelling in close proximity thereto and within the illumination zone 36. Further the microlouvers are operable to substantially inhibit or block light emitted by the light source 70 from travelling along the first component 34 of the first line of sight 31 and into the operator's vision thereby detracting him.

Claims: A combined mirror and visual signaling apparatus comprising a housing (50) with an aperture (61), a semi-transparent mirror (110) substantially occluding the aperture (61), a light source (70) mounted inside the housing (50) which generates light of a predetermined band of wavelengths, and a baffling assembly (100) between the light source (70) and the mirror (110), the baffling assembly (100) having louvers (102) which direct the light from the light source (70) into a predetermined direction and which substantially inhibits the light from emanating in directions other than the predetermined direction, characterized in that the semi-transparent mirror is dichroic and adapted to transmit light in said predetermined band of wavelengths. Apparatus according to claim 1, characterized in that the light source (70) comprises at least one lamp (75, 81, 91) having a beam center aligned with the predetermined direction. Apparatus according to claim 1, characterized in that the predetermined wavelengths band ranges from 600 to 700 nm. Apparatus according to claim 1 or 3, characterized in that the dichroic mirror (110) reflects 75% (average) visible spectrum wavelengths, and transmits substantially 58% (average) wavelengths. Apparatus according to claims 1 and 4, characterized in that the light source (70) emits light having wave lengths longer than those in the visible spectrum , and in that the longer wavelengths constitute radiant heat energy, and the mirror (110) is adapted to substantially transmit the longer wavelengths, thereby inhibiting production of heat within the housing (50). Apparatus according to any of the preceding claims, characterized in that the baffling assembly includes a light control film (101) having a plurality of substantially parallel, equally spaced microlouvers (105).

Inventors: ROBERTS JOHN K, ROBERTS, JOHN K.
Applicants: MUTH K W CO INC, K.W. MUTH COMPANY, INC.
Application year: 1990
Main classification: B60R1
IPC codes: B60Q1, B60R1, F21V9