Vehicular rear viewing device

• US 3,909,117 A
• Filed: 08/23/1973
• Issued: 09/30/1975
• Est. Priority Date: 08/25/1972
• Status: Expired due to Term

• Current Assignee: Ikuo Narusawa, Jun Kakei, Koichi Takahashi, Tadashi Hayashi
• Original Assignee: Ikuo Narusawa, Jun Kakei, Koichi Takahashi, Tadashi Hayashi
• Inventors: Takahashi, Koichi, Hayashi, Tadashi, Kakei, Jun, Narusawa, Ikuo
• Primary Examiner(s): Wibert, Ronald L.
• Assistant Examiner(s): Evans, F. L.
• Application Number:
  US05/390,854
• Time in Patent Office: 768 Days
• Field of Search: 350/301,302,303,304,307,52
• US Class Current: 359/630
• CPC Class Codes: B60K 2360/334 Projection means
• CPC Class Codes: B60R 1/10 Front-view mirror arrangements; specially adapted for covering the peripheral part of the vehicle B60R1/002; Periscope arrangements , i.e. optical devices using combinations of mirrors, lenses, prisms or the like specially adapted for covering the peripheral part of the vehicle B60R1/002; for viewing traffic-lights B60R1/005; Other mirror arrangements giving a view from above or under the vehicle
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/0154 with movable elements
• CPC Class Codes: G02B 2027/0165 associated with a head-down display
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence

Abstract

Three plane mirrors periscopically arranged to provide a clear rear view over the roof of a vehicle, including means to maintain constant image brightness over the entire field. A beam splitting mirror has a semi-transparent coating which may be preferably sectioned to at least two parallel lateral zones having respective thickness selected to provide desired relations between the light reflectance and transmittance in particular zones and between the light reflectance in one particular zone and the light transmittance in another particular zone to provide an image of a uniform brightness.

Claims

1. A vehicular rear viewing device for producing an erect image of the scene rearwardly of the device comprising, in combination, a first plane mirror having a rear reflecting surface to reflect an image of said scene, a second plane mirror having a front reflecting surface which is in angled vis-a-vis relation to the reflecting surface of said first plane mirror for forwardly redirecting the image reflected from the first plane mirror, and a third plane mirror having a rear reflecting surface which is in angled vis-a-vis relation to the reflecting surface of the second plane mirror and to a driver positioned relative to the third plane mirror for rearwardly reflecting the image from the second plane mirror toward the driver, wherein the second plane mirror is a beam splitting mirror by which the image coincident thereupon is partly reflected from its reflecting surface and partly transmitted therethrough, said second plane mirror comprising a first zone on which only the image from said scene is incident, a second zone on which the image from said scene and the image from said first plane mirror are incident, and a third zone on which only the image from said first plane mirror is incident, said first zone having a semi-transparent coating of a thickness which provides a transmittance higher than a reflectance in said first zone, said second zone having a semitransparent coating of a thickness which provides a transmittance and a reflectance substantially equal to each other in said second zone, said third zone having a semi-transparent coating of a thickness which provides a reflectance higher than a transmittance in said third zone, said transmittance of said first zone being substantially equal to said reflectance of said third zone.

2. A device as claimed in claim 1, in which the thicknesses of said semi-transparent coatings of two adjacent zones of said first, second and third zones have the same level at a boundary between said two adjacent zones and are continuously changed to said same level in the vicinity of said boundary.

3. A vehicular rear viewing device for producing an erect image of a scene rearwardly of the device comprising, in combination, a first plane mirror having a rear reflecting surface to reflect an image forwardly from said scene, a second plane mirror located substantially downwardly of said first plane mirror and having a front reflecting surface which is in angled vis-a-vis relation to the rear reflecting surface of said first plane mirror, the image of said scene being reflected downwardly from said first plane mirror toward the front reflecting surface of said second plane mirror, and a third plane mirror located forwardly of said second plane mirror and having a rear reflecting surface which is in angled vis-a-vis relation to the front reflecting surface of said second plane mirror and to a driver position rearwardly of the third plane mirror so that the image incident on the reflecting surface of the second plane mirror is forwardly re-directed toward the rear reflecting surface of said third plane mirror and re-directed rearwardly therefrom and transmitted through said second mirror to said driver, said second plane mirror comprising a first zone on which only the image from said first plane mirror is incident, a second zone on which the image from said first plane mirror and the image from said third planE mirror are incident, and a third zone on which only the image from said third plane mirror is incident, said first zone having a semi-transparent coating of a thickness which provides a reflectance higher than a transmittance in said first zone, said second zone having a semi-transparent coating of a thickness which provides a reflectance and a transmittance substantially equal to each other in said second zone, said third zone having a semi-transparent coating of a thickness which provides a transmittance higher than a reflectance in said third zone, said reflectance of said first zone being substantially equal to said transmittance of said third zone.

4. A device as claimed in claim 3, in which the thicknesses of said semi-transparent coatings of two adjacent zones of said first, second and third zones have the same level at a boundary between said two adjacent zones and are continuously changed to said same level in the vicinity of said boundary.

5. A vehicular rear viewing device for producing an erect image of a scene rearwardly of the device comprising, in combination, a first plane mirror having a rear reflecting surface to reflect an image of said scene, a second plane mirror located substantially downwardly of said first plane mirror and having a reflecting surface which is in angled vis-a-vis relation to the reflecting surface of the first plane mirror, the image of said scene being reflected downwardly from the rear reflecting surface of said first plane mirror toward the reflecting surface of the second plane mirror and a third plane mirror located downwardly of said first plane mirror and forwardly of said second plane mirror and having a rear reflecting surface which is in angled vis-a-vis relation to the reflecting surface of the second plane mirror and to a driver to be positioned relative to the third plane mirror, said third plane mirror being at least partly located between the reflecting surfaces of said first and second plane mirrors to cause one part of the image from said first plane mirror to pass through said third plane mirror to said second plane mirror and to cause the other part of the image from said first plane mirror to be directly incident on said second plane mirror without passing through said third plane mirror, the image incident on the second plane mirror being redirected upwardly and forwardly from the reflecting surface of the second plane mirror toward the rear reflecting surface of the third plane mirror and further re-directed rearwardly from the third plane mirror toward said driver, said third plane mirror comprising a first zone on which said one part of the image from said first plane mirror and the image from said second plane mirror are incident, and a second zone on which only the image from said second plane mirror is incident, said first zone having a semi-transparent coating of a thickness which provides a transmittance and a reflectance substantially equal to each other in said first zone, said second zone having a semi-transparent coating of a thickness which causes only reflection of the image from said second plane mirror.

6. A device as claimed in claim 5, in which the thicknesses of said semi-transparent coatings of said first and second zones have the same level at a boundary between said first and second zones and are continuously changed to said same level in the vicinity of said boundary.

7. A rear viewing device for a motor vehicle having a top wall structure which is formed with an opening in its front end portion, which device comprises a casing located above said opening and having a horizontally elongated opening formed at its rear end for facing substantially clear over said top wall structure a scene rearwardly of the vehicle, a first plane mirror supported on an inner face of the casing and having a rear reflecting surface on which an image of said scene is incident through said horizontally elongated opening in the casing, a second plane mirror which is stationary relative to said caSing and which has a front reflecting surface which is in angled vis-a-vis relation to the rear reflecting surface of said first plane mirror, and a third plane mirror located underneath said top wall structure and having a rear reflecting surface which is in angled vis-a-vis relation to the front reflecting surface of said second plane mirror and to a driver to be positioned relative to the third plane mirror for re-directing the image from said second plane mirror rearwardly toward the driver, wherein the second plane mirror is a beam splitting mirror by which the image incident thereupon is partly reflected from its reflecting surface and partly transmitted therethrough, said second plane mirror comprising a first zone on which only the image from said scene is incident, a second zone on which the image from said scene and the image from said first plane mirror are incident, and a third zone on which only the image from said first plane mirror is incident, said first zone having a semi-transparent coating of a thickness which provides a transmittance higher than a reflectance in said first zone, said second zone having a semi-transparent coating of a thickness which provides a transmittance and a reflectance substantially equal to each other in said second zone, said third zone having a semi-transparent coating of a thickness which provides a reflectance higher than a transmittance in said third zone, said transmittance of said first zone being substantially equal to the reflectance of said third zone.

8. A device as claimed in claim 7, further comprising means pivotally supporting said third plane mirror so that the plane mirror is angle adjustable with respect to a horizontal plane.

9. A device as claimed in claim 7, in which said second plane mirror is located rearwardly of said first plane mirror and above said top wall structure of the vehicle so that the image of said scene is transmitted through the second plane mirror to the first plane mirror and the image reflected from the first plane mirror is re-directed downwardly and forwardly toward said third plane mirror through said opening in said top wall structure, after reflecting from said second plane mirror.

10. A vehicular rear viewing device for producing an erect image of the scene rearwardly of the device comprising, in combination, a first plane mirror having a rear reflecting surface to reflect an image of said scene, a second plane mirror having a front reflecting surface which is in angled vis-a-vis relation to the reflecting surface of said first plane mirror for forwardly redirecting the image reflected from the first plane mirror, and a third plane mirror having a rear reflecting surface which is in angled vis-a-vis relation to the reflecting surface of the second plane mirror and to a driver positioned relative to the third plane mirror for rearwardly reflecting the image from the second plane mirror toward the driver, wherein the third plane mirror is a beam splitting mirror by which the image incident thereupon is partly reflected from its reflecting surface and partly transmitted therethrough, said third plane mirror comprising a first zone having a semi-transparent coating of a thickness which provides a transmittance and a reflectance substantially equal to each other in said first zone, and a second zone having a semi-transparent coating of a thickness which causes only reflection of the image.

11. A rear viewing device for a motor vehicle having a top wall structure which is formed with an opening in its front end portion, which device comprises a casing located above said opening and having a horizontally elongated opening formed at its rear end for facing substantially clear over said top wall structure a scene rearwardly of the vehicle, a first plane mirror supported on an inner face of the casing and having a rear reflecting surface on which an image of said scene is incident through said horizontally elongated opening in the casing, a second plane mirror which is stationAry relative to said casing and which has a front reflecting surface which is in angled vis-a-vis relation to the rear reflecting surface of said first plane mirror, and a third plane mirror located underneath said top wall structure and having a rear reflecting surface which is in angled vis-a-vis relation to the front reflecting surface of said second plane mirror and to a driver to be positioned relative to the third plane mirror for redirecting the image from said second plane mirror rearwardly toward the driver, wherein the second plane mirror is a beam splitting mirror by which the image incident thereupon is partly reflected from its reflecting surface and partly transmitted therethrough, said second plane mirror comprising a first zone on which only the image from said first plane mirror is incident, a second zone on which the image from said first plane mirror and the image from said third plane mirror are incident, and a third zone on which only the image from said third plane mirror is incident, said first zone having a semi-transparent coating of a thickness which provides a reflectance higher than a transmittance in said first zone, said second zone having a semi-transparent coating of a thickness which provides a reflectance and a transmittance substantially equal to each other in said second zone, said third zone having a semi-transparent coating of a thickness which provides a transmittance higher than a reflectance in said third zone, said reflectance of said first zone being substantially equal to said transmittance of said third zone.

12. A rear viewing device for a motor vehicle having a top wall structure which is formed with an opening in its front end portion, which device comprises a casing located above said opening and having a horizontally elongated opening formed at its rear end for facing substantially clear over said top wall structure a scene rearwardly of the vehicle, a first plane mirror supported on an inner face of the casing and having a rear reflecting surface on which an image of said scene is incident through said horizontally elongated opening in the casing, a second plane mirror which is stationary relative to said casing and which has a front reflecting surface which is in angled vis-a-vis relation to the rear reflecting surface of said first plane mirror, and a third plane mirror located underneath said top wall structure and having a rear reflecting surface which is in angled vis-a-vis relation to the front reflecting surface of said second plane mirror and to a driver to be positioned relative to the third plane mirror for re-directing the image from said second plane mirror rearwardly toward the driver, wherein the third plane mirror is a beam splitting mirror by which the image incident thereupon is partly reflected from its reflecting surface and partly reflected from its reflecting surface and partly transmitted therethrough, said third plane mirror being at least partly located between the reflecting surfaces of said first and second plane mirrors to cause one part of the image from said first plane mirror to pass through said third plane mirror to said second plane mirror and the other part of the image from said first plane mirror to be directly incident on said second plane mirror without passing through said third plane mirror, said third plane mirror comprising a first zone on which said one part of the image from said first plane mirror and the image from said second plane mirror are incident, and a second zone on which only the image from said second plane mirror is incident said first zone having a semi-transparent coating of a thickness which provides a transmittance and a reflectance substantially equal to each other in said first zone, said second zone having a semi-transparent coating of a thickness which causes only reflection of the image from said second plane mirror.

13. A vehicular rear viewing device for producing an erect image of the scene rearwardly of the device comprising, in combination, a first plane mirror having a rear reflecting surface to reflect an image of said scene, a second plane mirror having a front reflecting surface which is in angled vis-a-vis relation to the reflecting surface of said first plane mirror for forwardly redirecting the image reflected from the first plane mirror, and a third plane mirror having a rear reflecting surface which is in angled vis-a-vis relation to the reflecting surface of the second plane mirror and to a driver positioned relative to the third plane mirror for rearwardly reflecting the image from the second plane mirror toward the driver, wherein the second plane mirror is a beam splitting mirror by which the image incident thereupon is partly reflected from its reflecting surface and partly transmitted therethrough, said second plane mirror comprising a first zone on which only the image from said first plane mirror is incident, a second zone on which the image from said first plane mirror and the image from said third plane mirror are incident, and a third zone on which only the image from said third plane mirror is incident, said first zone having a semi-transparent coating of a thickness which provides a reflectance higher than a transmittance in said first zone, said second zone having a semi-transparent coating of a thickness which provides a reflectance and a transmittance substantially equal to each other in said second zone, said third zone having a semi-transparent coating of a thickness which provides a transmittance higher than a reflectance in said third zone, said reflectance of said first zone being substantially equal to said transmittance of said third zone.