VEHICULAR REARVIEW MIRROR WITH INCREASED FIELD-OF-VIEW

• US 20120099173A1
• Filed: 10/22/2011
• Published: 04/26/2012
• Est. Priority Date: 10/25/2010
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Gentry, Nathaniel J., Roush, Robert E. Jr.
• Granted Patent: US 8,817,356 B2
• Time in Patent Office: Days
• US Class Current: 359/265
• CPC Class Codes: B60R 1/02 Rear-view mirror arrangements periscope arrangements B60R1/10
• CPC Class Codes: B60R 1/06 mounted on vehicle exterior B60R1/025, B60R1/08 take precedence
• CPC Class Codes: B60R 1/08 involving special optical features, e.g. avoiding blind spots , e.g. convex mirrors; Side-by-side associations of rear-view and other mirrors B60R1/025, B60R1/10 take precedence
• CPC Class Codes: B60R 1/081 avoiding blind spots, e.g. by using a side-by-side association of mirrors
• CPC Class Codes: B60R 1/082 using a single wide field mirror or an association of rigidly connected mirrors
• CPC Class Codes: F21V 7/09 with a combination of different curvatures
• CPC Class Codes: G02B 17/06 using mirrors only , i.e. having only one curved mirror used in non-imaging applications G02B19/00
• CPC Class Codes: G02B 5/08 Mirrors vehicle mirrors involving special optical features B60R1/08
• CPC Class Codes: G02B 5/10 with curved faces
• CPC Class Codes: G02F 1/153 Constructional details
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

An optical element such as a reflector defining a differentiable fiducial surface having a first portion, with a flat region, that seamlessly adjoins, along a curved line, a second portion having a two-dimensionally curved region. The quality of optical imaging in the reflector is drastically improved by reducing the ratio of optical powers measured in two perpendicular directions along the two-dimensionally curved portion of the surface. The vehicular rearview assembly including such a reflector possesses a field-of-view (FOV) that is significantly higher than the FOV of a conventional flat mirror and facilitates visual access to a “blind spot” behind the vehicle.

Claims

1. An optical substrate, comprising:

a substrate boundary defining a surface that includes

a substantially flat portion having a first perimeter; and

a two-dimensionally (2D) curved portion having a second perimeter, the 2D-curved portion seamlessly adjoining said flat portion along a curved line that is shared by the first and second perimeters,

wherein the surface is differentiable.

2. An optical substrate according to claim 1, wherein said curved line has a radius greater than 150 mm.

3. An optical substrate according to claim 1, wherein said substrate comprises at least one of glass and polymer material.

4. An optical substrate according to claim 1, wherein the substantially flat portion has an optical power, averaged over the area of said substantially flat portion, which does not exceed 250 millidiopters.

5. An optical substrate according to claim 4, wherein an optical power of the substantially flat portion changes at a rate not exceeding 250 millidiopters per 10 mm of displacement across said substantially flat portion.

6. An optical substrate according to claim 1, wherein the substantially flat portion has an optical power, averaged over the area of said substantially flat portion, which does not exceed 100 millidiopters.

7. An optical substrate according to claim 6, wherein an optical power of the substantially flat portion changes at a rate not exceeding 100 millidiopters per 10 mm of displacement across said substantially flat portion.

8. An optical substrate according to claim 6, wherein an optical power of the substantially flat substrate changes at a rate not exceeding 10 millidiopters per 1 mm of displacement across said substantially flat portion.

9. An optical substrate according to claim 1 that is rotationally-symmetric about an axis transverse to said substantially flat portion.

10. An optical substrate according to claim 1 that defines a portion of a rotationally-symmetric surface.

11. An optical substrate according to claim 1, wherein said 2D-curved portion is characterized by a first optical power measured across said 2D-curved portion in a first direction and a second optical power measured across said 2D-curved portion in a second direction, and wherein a ratio of said first and second optical powers does not exceed 1000.

12. An optical substrate according to claim 1, wherein said 2D-curved portion is characterized by a first optical power measured across said 2D-curved portion in a first direction and a second optical power measured across said 2D-curved portion in a second direction, and wherein a ratio of said first and second optical powers does not exceed 500.

13. An optical substrate according to claim 1, wherein said 2D-curved portion is characterized by a first optical power measured across said 2D-curved portion in a first direction and a second optical power measured across said 2D-curved portion in a second direction, and wherein a ratio of said first and second optical powers does not exceed 100.

14. An optical substrate according to claim 1, configured as part of an electrochromic (EC) element.

15. An optical reflector comprising:

a primary optical element having a perimeter, a first substantially flat portion, and a second portion that is curved in two dimensions, the second portion adjoining said first portion along a curved line, wherein the perimeter defines a primary differentiable surface; and

a layer of reflective material on said primary optical element.

16. An optical reflector according to claim 15, wherein the first portion has an optical power, averaged over the area of said first portion, which does not exceed 250 millidiopters, and wherein said curved line has a radius greater than 150 mm.

17. An optical reflector according to claim 16, wherein said optical power of the first portion changes at a rate not exceeding 250 millidiopters per 10 mm of displacement across said first portion.

18. An optical reflector according to claim 15, further comprising a secondary optical element having a perimeter that defines a secondary differentiable surface and disposed next to the primary optical substrate such as to form a spaced-apart and tangentially-parallel relationship between the primary and secondary differentiable surfaces,

wherein an angular deviation between two beams of light, formed by the reflectance of an incident collimated beam of light off of the primary and secondary differentiable surfaces does not exceed 12 arcminutes.

19. An optical reflector according to claim 15, further comprising a secondary optical element having a perimeter that defines a secondary differentiable surface and disposed next to the primary optical substrate such as to form a spaced-apart and tangentially-parallel relationship between the primary and secondary differentiable surfaces,

wherein an angular deviation between two beams of light, formed by the reflectance of an incident collimated beam of light off of the primary and secondary differentiable surfaces does not exceed 9 arcminutes.

20. An optical reflector according to claim 15 configured as part of a rearview assembly that further comprises at least one of a light source positioned to project light through the first optical element, a blind spot indicator, a keyhole illuminator, a puddle light, a turn signal, a photo sensor, an illumination assembly, a display, a telemetry system, and a heater.

21. An electrochromic (EC) mirror element having a front and comprising:

a first substrate having a first surface, the first substrate corresponding to the front;

a second substrate having a second surface, the first and second substrates disposed in a spaced-apart and tangentially-parallel relationship with one another such as to form a gap between the first and second surfaces; and

an EC medium in the gap,

wherein each of the first and second surfaces is differentiable and includes a substantially flat portion and a two-dimensionally (2D) curved portion that adjoins said flat portion along a curved line.

22. An EC mirror element according to claim 21, wherein the first substrate carries a reflective coating configured as a circumferential ring around a perimeter of said first substrate.

23. An EC mirror element according to claim 21, configured such that angular deviation between images, formed by the first and second substrates in reflection of light incident onto a substantially flat portion of the first substrate from the front, does not exceed 12 arcminutes.

24. An EC mirror element according to claim 21, configured such that angular deviation between images, formed by the first and second substrates in reflection of light incident onto a substantially flat portion of the first substrate from the front, does not exceed 9 arcminutes.

25. An EC element according to claim 21, configured as part of a rearview assembly that further comprises at least one of a light source positioned to project light through the first optical element, a blind spot indicator, a keyhole illuminator, a puddle light, a turn signal, a photo sensor, an illumination assembly, a display, a telemetry system, and a heater.

26. An electrochromic (EC) mirror element comprising:

a first substrate having a first surface, the first substrate corresponding to the front;

a second substrate having a second surface, the first and second substrates disposed in a spaced-apart and tangentially-parallel relationship with one another such as to form a gap between the first and second surfaces; and

an EC medium in the gap,

wherein each of the first and second surfaces is differentiable and includes a substantially flat portion and a one-dimensionally (1D) curved portion that adjoins said flat portion along a straight line.

27. An EC mirror element according to claim 26, wherein the first substrate carries a reflective coating configured as a circumferential ring around a perimeter of said first substrate.

28. An EC mirror element according to claim 26, configured such that angular deviation between images, formed by the first and second substrates in reflection of light incident onto a substantially flat portion of the first substrate from the front, does not exceed 12 arcminutes.

29. An EC mirror element according to claim 26, configured such that angular deviation between images, formed by the first and second substrates in reflection of light incident onto a substantially flat portion of the first substrate from the front, does not exceed 9 arcminutes.

30. An EC element according to claim 26 configured as part of a rearview assembly that further comprises at least one of a light source positioned to project light through the first optical element, a blind spot indicator, a keyhole illuminator, a puddle light, a turn signal, a photo sensor, an illumination assembly, a display, a telemetry system, and a heater.

31. A method for assembly of an optical reflector, the method comprising:

positioning first and second substrates that define, respectively, first and second differentiable surfaces, such as to define a spaced-apart and tangentially-parallel relationship between the first and second differentiable surfaces; and

disposing an electrochromic (EC) medium in a gap between said first and second differentiable surfaces,

wherein the first differentiable surface includes a substantially flat portion and a second portion that is one-dimensionally (1D) curved, the substantially flat and 1D-curved portions of the first differentiable substrate adjoining each other along a first line, and

wherein the second differentiable surface includes another substantially flat portion and another portion that is one-dimensionally (1D) curved, the substantially flat and 1D-curved portions of the second differentiable substrate adjoining each other along a second line.

32. A method according to claim 31, further comprising cutting at least one of the first and second optical substrates from a rotationally-symmetric pre-form.

33. A method according to claim 31, further comprising disposing at least one of reflective and electrically-conductive coatings on at least one of said differentiable surfaces of the first and second substrates.

34. A method according to claim 31, further comprising depositing a layer of substantially opaque material on a surface of the first substrate, said layer configured as a ring around a perimeter of said surface.

35. A method according to claim 31, wherein positioning first and second substrates includes positioning said substrates such that an angular deviation between the corresponding substantially flat portions of the first and second substrates does not exceed about 4.5 arcminutes.

36. A method according to claim 31, further comprising disposing a seal material in said gap such around a perimeter of the first substrate such as to affix said first and second substrates together.

37. A method according to claim 31, wherein the first and second lines are straight lines.

38. A method according to claim 31, wherein positioning first and second substrates includes positioning first and second substrates that are substantially congruent.