Optical: systems and elements – Prism
Reexamination Certificate
2001-07-17
2003-07-01
Sikder, Mohammad (Department: 2809)
Optical: systems and elements
Prism
C359S833000, C359S834000
Reexamination Certificate
active
06587285
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vehicle periphery visual confirmation apparatus which, under a poor visibility condition, takes a picture of a peripheral scene before or behind a vehicle, or, a picture of the right-side or left-side scene oft he vehicle, that is, the scene of a blind spot to a driver, and displays the picture of such vehicle peripheral scene to the driver.
2. Description of the Related Art
FIG. 5
shows the structure of a conventional vehicle periphery visual confirmation apparatus. This vehicle periphery visual confirmation apparatus
1
comprises a picture camera apparatus
11
disposed on the outside portion of a vehicle to take pictures of two vehicle peripheral scenes existing in the mutually opposite directions, a mirror image reversal processing part
12
for mirror-image processing picture signals supplied from the picture camera apparatus
11
, and a display part
15
disposed within a vehicle room for displaying the picture images obtained from the mirror image reversal processing part
12
.
The picture camera apparatus
11
comprises: a lightproof case
3
on the two sides of which there are formed a pair of left and right penetration window portions
2
L,
2
R each made of transparent glass; a prism
4
having an isosceles-triangular-shaped section stored in the interior portion of the case
3
and disposed in such an attitude that its vertical angle portion
5
faces the front portion of the case
3
(in
FIG. 5
, the upper portion of the case
3
) and its prism side surfaces
8
L,
8
R respectively face the left and right penetration window portions
2
L,
2
R; and, an imaging device
10
stored and disposed in the rear of the prism
4
for converting light rays
18
L,
18
R into image signals. Here, referring specifically to the light rays
18
L,
18
R, they enter the prism side surfaces
8
L,
8
R, their respective light paths are changed within the prism
4
, and then they are guided through a given imaging lens
9
onto the imaging surface of the imaging device
10
. In this structure, the imaging lens
9
is disposed in the rear of the prism
4
(in
FIG. 5
, in the lower portion) in such a manner that the optical axis
25
of the imaging lens
9
is coincident with the bisector of the vertical angle portion of the isosceles-triangular-shaped section of the prism
4
.
The thus structured picture camera apparatus
11
is mounted on the front bumper or front grille of the vehicle in such a manner that, for example, the front portion of the picture camera apparatus
11
(the front portion of the case
3
) faces forwardly of the vehicle and the penetration window portions
2
R.
2
L respectively face on the right and left sides of the vehicle.
In this state, the light ray
18
L corresponding to the scene of the left side of the vehicle, as shown in
FIG. 5
, penetrates through the penetration window portion
2
L and prism side surface
8
L, advances through the interior portion of the prism
4
and reaches the prism side surface
8
R. And, the light ray
18
L is then internally reflected by the prism side surface
8
R, is radiated from the prism side surface
8
R, is image formed by the imaging lens
9
, and is guided to the left half surface
10
L of the imaging surface of the imaging device
10
.
In the case of the light ray
18
R which corresponds to the right-side scene of the vehicle, as the light rays
18
L and
18
R are symmetric, the light ray
18
R is similarly guided to the right half surface
10
L of the imaging surface of the imaging device
10
. And, both of the light rays
18
L,
18
R are converted into image signals by the imaging device
10
.
The pictures of the left-side and right-side scenes are taken in this manner, the image signals of the pictures are mirror image reversal processed by the mirror image reversal processing part
12
, and, as shown in
FIG. 6
, are supplied to the display part
15
. In the display part
15
, the left-side scene taken in from the penetration window portion
2
L is displayed on the left half screen
15
L of the display part
15
as a left-side scene image
19
L, whereas the right-side scene taken in from the penetration window portion
2
R is displayed on the right half screen
15
R of the display part
15
as a right-side scene image
19
R.
However, in the conventional vehicle periphery visual confirmation apparatus, there is a fear that part of the other picture can come out in one picture, that is, an image like a vision (which is hereinafter referred to as a vision image) can appear, thereby degrading the visibility of the picture. For example, as shown in
FIG. 5
, let us assume a case in which, at night, a vehicle with a headlight
20
on approaches our vehicle slightly from the right side. In this case, after the light of the headlight
20
penetrates through the right-side penetration window portion
2
R, part of the light passes through the adjacent portion of the vertical angle portion of the prism
4
and reaches the left-side penetration window portion
2
L. Here, about 96% of the light that has arrived at the left-side penetration window portion
2
L penetrates through the left-side penetration window portion
2
L, whereas the remaining light
21
, namely, about 3% of the light is reflected by the internal surface of the left-side penetration window portion
2
L. As a result of this, the light
21
is allowed to enter the left-side prism side surface
8
L. The light
21
, which has entered the left-side prism side surface
8
L in this manner, advances through the interior portion of the prism
4
, reaches the right-side prism side surface
8
R, and is reflected by the internal surface of the right-side prism side surface
8
R; and, after then, the light
21
is radiated from the prism rear surface
8
B of the prism
4
, is image formed by the imaging lens
9
, and is guided to the left half surface
10
L of the imaging surface of the imaging device
10
.
In other words, in the present case, the partial light
21
of the light from the headlight
20
, which ought to be situated on the right side, is image formed by the imaging lens
9
while it is overlapped with the light ray
18
L entering from the left side, and is guided to the left half surface
10
L of the imaging surface of the imaging device
10
; and, the thus-formed image is displayed on the left half screen
15
L of the display part
15
as the left-side scene image.
SUMMARY OF THE INVENTION
The present invention aims at eliminating the above drawbacks found in the conventional vehicle periphery visual confirmation apparatus. Accordingly, it is an object of the invention to provide a vehicle periphery visual confirmation apparatus capable of preventing occurrence of a vision image which is caused when light entering from the outside through one of right and left penetration window portions passes through the adjacent area of the vertical angle portion of the right and left prism side surfaces of a prism and is then reflected by the opposite-side penetration window portion.
In attaining the above object, according to a first aspect of the invention, there is provided a vehicle periphery visual confirmation apparatus comprising a picture camera apparatus disposed on the outside of a vehicle, the picture camera apparatus comprising: a case including a pair of right and left penetration window portions respectively formed on the two sides thereof; a prism having an isosceles-triangular-shaped section and disposed within the case in such an attitude that its vertical angle portion faces the front portion of the case and its right and left prism side surfaces corresponding to the two equal sides of its isosceles triangle shape respectively face the right and right penetration window portions; and, an imaging device which is disposed in the rear of the prism and also which, when light rays entering from one of the right and left prism side surfaces are reflected by the other of the right and left prism side surfaces and are radiated from the prism rear surface of the prism
Autonetworks Technologies Ltd.
Sikder Mohammad
LandOfFree
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