HRP930244A2 - Inside rear-view mirror supressing specular reflections coming from a rear window - Google Patents

Description

Technical field to which the invention relates:

The invention relates to an interior car rearview mirror that has the ability to suppress the specular image seen in the rear car window. The specular image is created by the specular reflection of light on the smooth surfaces of the rear car window, where the light originates from objects placed on the rear car shelf, and the shelf is located under the rear car window.

Technical problem for which patent protection is requested:

The technical problem for the solution of which patent protection is sought is how to eliminate the specular image in the field of view of the interior car rearview mirror, which is formed on the rear car window by the specular reflection of light originating from objects placed on the rear shelf under the rear car window, and to enable the interior rearview mirror to see through rear window clear image of the traffic situation behind the car, without the annoying specular image of objects.

State of the art:

Interior car mirrors, which are now used in passenger cars, allow the driver to look through the rear window of the car, but at the same time the driver sees in the rear window also a mirror image of objects that have been placed on the rear car shelf. The mirror image of the object is formed by the smooth surfaces of the rear window, which specularly reflect the light coming from the objects, which are placed on the rear car shelf, located under the rear car window.

The rear window, which is tilted forward in most passenger cars, directs specularly reflected light in the direction of the rearview mirror. In this way, the driver simultaneously sees in the rearview mirror the mirror image of the object, which is created by the specular reflection on the rear window, and the image of the traffic situation behind the car.

The image of the object, created by specular reflection, bothers the driver and requires a longer look in the rearview mirror, which can be potentially dangerous in traffic.

Until now, the problem of reducing the intensity of the specularly reflected image was solved by covering the rear shelf with a dark absorbing material. However, such a solution requires that the rear shelf is always empty, which means that no objects may be placed on the rear shelf, and thus the shelf does not serve its purpose.

Presentation of the essence of the invention:

The problem of how to eliminate the specular image formed on the rear car window in the field of view of the interior car rearview mirror and at the same time enable a clear view through the rear car window is solved by placing a vertical linear polarizer in front of the reflective layer in the rearview mirror. A specularly reflected image is created by the reflection of light on the smooth surfaces of the rear car window. The light originates from objects stored under the rear car window. The light is specularly reflected at an angle that is close to Brewster's angle in most cars. In this way, the light is mostly horizontally polarized. After this light enters the rearview mirror, the vertical linear polarizer almost completely absorbs this mostly horizontally polarized light, which is the specularly reflected image from the rear car window. However, the light that carries the image of the traffic situation behind the car, and enters through the rear window, is non-polarized, i.e. it consists in equal proportions of horizontally and vertically polarized parts, and after passing through the rearview mirror, the vertically polarized part of this light reaches the driver and allows the driver view of the traffic situation behind the car.

Technical novelty of the invention:

The technical novelty of the rear-view mirror invention is that the back shelf of the car can be used to store objects, and that the specularly reflected image of these objects, created by the rear car window, does not hinder the driver from seeing a clear image of the traffic behind the car through the rear car window.

A brief description of the blueprint images:

Figure 1 is a schematic cross-section of a preferred embodiment of the invention-rearview mirror.

Figure 2 is a schematic section of the variant of the invention-rearview mirror from Figure 1.

Figure 3 is a schematic diagram illustrating the operation of the preferred embodiment of the invention of the mirror of Figure 1.

Figure 4 is a schematic section of an alternative embodiment of the invention-rearview mirror, and a representation of the effect of the invention-rearview mirror on incident light.

Figure 5 is a schematic cross-section of the adaptive version of the invention-rearview mirror, which is attached as an adaptive rearview mirror to the already existing rearview mirror in the car.

A detailed description of at least one of the ways of realizing the invention with examples of implementation and reference to the draft:

According to Figure 1, the preferred embodiment of the interior car rearview mirror (1) for suppressing specular reflections from the rear window of the car consists of a mechanical armature (2) and an optical system (3).

The mechanical armature (2) is composed of a holder (4) that fastens the rear-view mirror (1) to the roof of the cabin or to the windshield of the car, a hinge (5) that allows the rear-view mirror (1) to be adjusted according to the driver's eyes, a housing (6) for the optical system ( 3) and the switch (7) which switches the rearview mirror (1) from the "functional" to the "night" position.

The optical system (3) consists of a vertical linear polarizer (8) which is laminated between a transparent wedge-shaped plate (9) on the back of which a reflective layer (10) is applied and a transparent plan-parallel plate (11) which serves as a protective plate.

The wedge plate (9) is, in this example of the invention, turned with the wedge upwards although the invention works well with the wedge plate facing the wedge downwards. The material for making the wedge plate is primarily glass, due to its good optical and mechanical properties, although plastic can also be used.

The vertical linear polarizer (8) is a leaf-type polarizer. The plane-parallel transparent plate (11) serves to protect the polarizer (8) from mechanical damage, for example when cleaning the rear-view mirror when the entrance surface of the rear-view mirror (12) is most exposed. The most suitable material for the plano-parallel plate (11) is glass, due to its good mechanical and optical properties, although resistant plastic can also be used. However, if the vertical linear polarizer (8) is sufficiently rigid and hard, the plane-parallel plate (11) can be omitted.

The reflective layer (10) is usually made of silver or aluminum.

According to Figure 2, a variant of the rearview mirror (1) for suppressing specular reflections from the rear window of the car consists of the same elements and functions in the same way as the preferred embodiment described in Figure 1.

The difference is that the transparent plane-parallel plate (11) and the transparent wedge plate (9) have switched places. In this embodiment, the reflective layer (10) is applied to the non-laminated surface of the plane-parallel plate (11), and the non-laminated surface of the wedge plate (9) is the input surface (12) of the rearview mirror (1). The wedge plate (9) has an additional purpose as a protective plate of the vertical linear polarizer (8). Again, the invention works well when the wedge plate is turned with the wedge down.

Again, if the vertical linear polarizer (8) is sufficiently rigid, the transparent plane-parallel plate (11) can be omitted.

According to Figure 3, the interior rearview mirror functions as follows to absorb specular reflections from the rear window and provide a clear view through the rear window.

The light (13), which entered through the rear car window (14), moves in the direction of the rearview mirror (1) and carries an image of the traffic situation behind the car. The light (13) is unpolarized, i.e. it is composed in equal proportions of vertically (15) and horizontally (16) polarized light. When the light (13) falls on the entrance surface (12) of the rear-view mirror (1), it is partially reflected Specularly as light (17), and most of it is refracted into a transparent plane-parallel plate (11).

Specularly reflected light (17) is composed in equal proportions of vertically (15) and horizontally (16) polarized light, as well as light (13), only of significantly lower intensity. After entering the plate (11), the refracted part of the light (13) passes through the plate (11) and enters the vertical linear polarizer (8). The polarizer (8) has absorption axes in the horizontal direction, so it will pass only that part of the refracted light (13) that is vertically polarized. The vertically polarized part of the refracted light (13) exits the vertical polarizer (8), passes through the transparent wedge plate (9) and is reflected on the reflective layer (10), and again passes through the wedge plate (9), without changing it passes through the vertical linear polarizer (8), and after passing through the transparent plane-parallel plate (11), exits the rearview mirror (1) as light (18) of vertical polarization (15). The light (18), which carries an image of the traffic situation behind the car, reaches the eyes of the driver (19) and enables him to see the traffic situation behind the car.

The external light (20) which comes from the sun during the day and from the street lights at night, passes through the rear car window (14) and illuminates the objects (21) that are placed on the rear shelf (22). The light (23) that originates from the object (21) and carries the image of the object (21) is unpolarized, i.e. it consists in equal proportions of vertically (24) and horizontally (25) polarized light.

The rear window (14) in most passenger cars is angled significantly forward, so the light (23) will fall on the rear window surfaces at an angle that is generally close to Brewster's angle. Light (23) is specularly reflected on the smooth surfaces of the rear window (14) as light (26). The specularly reflected light (26), which carries the image of the object (21), is mainly of horizontal polarization (25), because it was reflected on the surfaces of the rear window (14) at an angle mostly close to Brewster's angle. The closer the angle of reflection and thus the angle of incidence is to the Brewster angle, the lower the intensity of the vertically polarized component in specularly reflected light, and the higher the intensity of the horizontally polarized component. When the reflection angle of the specularly reflected light is equal to Brewster's angle, the specularly reflected light is purely horizontal polarized. When the light (26) falls on the smooth entrance surface (12) of the rearview mirror (1), it is partially specularly reflected as light (27), which remains horizontally polarized (25). Most of the light (26) is refracted into a transparent plane-parallel plate (11) while remaining horizontally polarized, and after passing through it enters the vertical linear polarizer (8). The polarizer (8), which has absorption axes in the horizontal direction, mainly absorbs the refracted part of the light (26) because it is mainly of horizontal polarization (25). In this way, the light (26) that is specularly reflected on the rear window (14) and carries the image of the object (21) does not reach the driver's eyes (19). The only light (18) of vertical polarization (15) reaches the driver's eyes (19), which carries a clear picture of the traffic situation behind the car. The light (27), which is specularly reflected on the smooth surface (12) of the rearview mirror (1), carries the image of the objects (21) located on the rear shelf (22). The light direction (27) needs to be separated from the light direction (18), so that only the image of the traffic situation behind the car, which is carried by the light (18), reaches the driver's eyes (19). For this purpose, a wedge plate (9) is used, whose wedge angle is chosen in such a way that when the driver (19) sees the light (18), he cannot see the light (27) at the same time.

The position of the rearview mirror (1) in which only the light (18) reaches the driver's eyes (19), which carries only the image of the traffic situation behind the car, is the "functional" position of the rearview mirror (1), because the invention works in this position of the rearview mirror. Using the switch (7), it is possible to partially turn the rearview mirror (1) and switch it to the "night" position. This position is used at night in case the car from behind blinds the driver's eyes with its high beams (19). In the "night" position of the rearview mirror (1), the driver sees a light (17) that carries an image of the traffic situation behind the car, but it is much weaker in intensity than the light (18). However, in the "night" position of the rearview mirror (1), together with the light (17), the driver's eyes (19) also see the light (27) which is in the same direction as the light (17), and carries the image of the object (21). Therefore, in the "night" position of the rearview mirror (1), the invention does not work, because the image of the situation behind the car is covered with the image of the object (21) from the rear shelf (22) of the car, and in this position of the rearview mirror, the advantages of the invention are not used.

According to Figure 4, an alternative version of the interior mirror (1) for suppressing specular reflections from the rear car window consists of a mechanical armature (28) and an optical system (29).

In an alternative version, the mechanical armature (28) consists of a holder (4) for attaching the rear-view mirror (1) to the roof of the car cabin or to the windshield of the car, a joint (5) for adjusting the rear-view mirror (1) to the driver's eyes (19) so that the driver in the rearview mirror had a view through the rear window of the car and the housing (30) for the optical system (29). In this embodiment of the invention, the mechanical armature (28) does not have the ability to switch the mirror from the "functional" to the "night" position as was possible in the preferred embodiment of the invention shown in Figure 1 and in the variant of the preferred embodiment shown in Figure 2, but the rear-view mirror (1) once the driver adjusts it to the desired position, is always in that position. The optical system (29) no longer contains the wedge plate (9), but it has been replaced by a transparent plane-parallel plate (31). In this way, the optical system (29) consists of a vertical linear polarizer (8) laminated between plane-parallel plates (11) and (31), where the unlaminated surface of the plate (31) is coated with a reflective layer (10), and the unlaminated surface of the plate (11) ) which is also the entrance surface (12) of the rearview mirror (1) is coated with an anti-reflective layer (32). The action of the optical system (29) of the interior mirror (1) on the light (13), which carries the image of the traffic situation behind the car and the light (26), which carries the specularly reflected image of the object (21) from the rear shelf (22), is similar to the action earlier of the described optical system (3) in the preferred embodiment of the invention. However, due to the replacement of the wedge-shaped plate (9) with a plane-parallel plate (31), the directions of propagation of the lights (18), (17) and (27) are the same. Because of this, the driver (19) sees the desired image of the traffic situation behind the car carried by the light (18), overlaid with an unwanted (disturbing) image of the object reflected from the rear window of the car carried by the light (27) and further overlaid with a shifted image of the traffic situation behind the car carries light (17). Although the lights (27) and (17) are significantly less intense than the light (18), since they are specular reflections of the lights (26) and (13), respectively, on the smooth entrance surface (12), they still interfere with the driver's perception of the situation behind the car . To further reduce the intensity of the lights (27) and (17), an anti-reflective layer (32) is used, which is applied to the smooth surface (12) of the plane-parallel plate (11), which minimizes the intensity of the mentioned lights.

The materials for the planar parallel plates (11) and (31), the polarizer (8) and the reflective layer (10) are the same as in the preferred embodiment of the invention. The material for making the anti-reflective layer (32) is, for example, MgF2.

If the polarizer is rigid enough, plates (11) and (31) can be omitted.

To increase the driver's viewing angle, the plates (11) and (31) and the vertical linear polarizer (8) laminated between them can be cylindrically or spherically curved.

According to Figure 5, the adaptive version of the rearview mirror (1) is a version of the rearview mirror that can be installed on the already existing interior rearview mirror in the car and consists of a mechanical armature (33) and an optical system (34). The mechanical armature (33) is reduced to a housing (35) for the optical system (34) and two straps (36) with which the rear-view mirror (1) is attached to the rear-view mirror (37) already in the car. The bands (36) are attached to the housing (35) at equidistant distances from the ends of the housing (35). The housing (35) is the already described housing (6) or (30), and the optical system (34) is the already described optical system (3) or (29), respectively.

Method of industrial or other application of the invention:

The way of industrial or other application of the invention can be seen from the description of the invention.

Claims (8)

1. Interior automotive rearview mirror (1) for suppressing specularly reflected light (26) from the rear automotive window (14), consisting of a mechanical armature (2) and an optical system (3), where a vertical linear polarizer (8) built into the optical system (3) of the rearview mirror (1) absorbs the specularly reflected light (26) that entered the optical system (3) of the rearview mirror (1), where the light (26) of mostly horizontal polarization (25) was created by the specular reflection of light (23) on smooth surfaces of the rear car window (14), where the light (23) originates from objects (21) placed on the rear car shelf (22), and where the vertical linear polarizer (8) transmits the vertically polarized component (15) of the unpolarized light (13) to the light (18) leaves the rearview mirror (1) and reaches the driver's eyes (19), and where the light (13) carries an image of the traffic situation behind the car, characterized by the fact that the mechanical armature (2) of the interior car rearview mirror (1) consists of d bracket (4) with which the rear-view mirror (1) is attached to the roof of the cabin or to the windshield of the car, the hinge (5) which allows the rear-view mirror (1) to be adjusted according to the driver's eyes, the housing (6) for the optical system (3) and the switch (7) which the rear-view mirror (1) is switched from the "functional" to the "night" position, that the optical part (3) of the rear-view mirror (1) consists of a vertical linear polarizer (8) laminated between a transparent wedge plate (9) facing the wedge upwards and a transparent plan-parallel plates (11) and that the wedge plate (9) on the non-laminated side is covered with a reflective layer (10) and that the wedge angle of the wedge plate (9) is such that the driver in the "functional" position of the rearview mirror sees only the light (18) that comes out of of the rearview mirror (1), which is a vertically polarized light component (13) that carries a clear image of the traffic situation behind the car, and in the "night" position of the rearview mirror (1), the lights (17) and (27) can be seen reflected on the smooth entrance surface (12) rearview mirror (1) where lights (17) and (27) nos e image of the traffic situation behind the car and image of objects (21) placed on the back shelf (22) respectively. 2. Interior car rearview mirror (1) for suppressing specularly reflected light (26) from the rear car window (14), according to patent claim 1, characterized in that the transparent wedge plate (9) is turned with the wedge downwards. 3. Interior car rearview mirror (1) for suppressing specularly reflected light (26) from the rear car window (14), according to patent claims 1 and 2, characterized in that the non-laminated surface of the transparent plane-parallel plate (11) is coated with a reflective layer (10) , and that the non-laminated surface of the transparent wedge plate (9) is the entrance surface of the rearview mirror (1). 4. Interior car rearview mirror (1) for suppressing specularly reflected light (26) from the rear car window (14), according to patent claims 1 to 3, characterized in that the transparent plate (11) is absent. 5. Interior car rearview mirror (1) for suppressing specularly reflected light (26) from the rear car window (14), according to patent claim 1, characterized in that the optical system (29) of the rearview mirror (1) consists of a vertical linear polarizer (8) ) laminated between two transparent plane-parallel plates (11) and (31), that the non-laminated side of the transparent plane-parallel plate (11) is coated with an anti-reflective layer (32) and that the non-laminated side of the transparent plate (31) is coated with a reflective layer (10) and that the mechanical armature (28) of the rear-view mirror (1) consists of a holder (4), a joint (5) and a housing (30) for the optical system (29). 6. Interior car rearview mirror (1) for suppressing specularly reflected light (26) from the rear car window (14), according to patent claims 1 and 5, characterized in that the transparent plane-parallel plate (11) or the transparent plane-parallel plate (31) or both are absent. 7. Interior car rearview mirror (1) for suppressing specularly reflected light (26) from the rear car window (14), according to patent claims 1 and 5, characterized in that the plates (11) and (31) and the vertical linear polarizer (8) are laminated between them are cylindrically or spherically curved. 8. Interior car rearview mirror (1) for suppressing specularly reflected light (26) from the rear car window (14), according to patent claims 1 to 6, characterized in that the mechanical armature (33) consists of the housing (35) of the optical system ( 34) and tightening straps (34) attached to the housing (35) at equidistant intervals from the ends of the housing, that the housing (35) is one of the already described housings (6) or (30), and the optical system (34) is one of the already described described optical systems (3) and (29), respectively.