JP2020104661A - Dead angle auxiliary device - Google Patents

Abstract

To provide a dead angle auxiliary device capable of suppressing a difference in luminosity.SOLUTION: In a dead angle auxiliary device comprising a transflective mirror 111 and a mirror 112, light progresses in a prescribed direction by being repeatedly reflected and a maximum of three times of reciprocation is allowed. A reflection plane of the transflective mirror 111 can be divided into first to third regions respectively corresponding to first to third emission lights each, in accordance with first to third emission lights Lout1 to Lout3 respectively with zero, one time and two times of reflections on the transflective mirror. Further, a fourth emission light Lout4 is directly emitted without being transmitted through the transflective mirror 111, and since a reflection rate of the reflection plane of the transflective mirror 111 switches at a border spot CK of the second region and the third region, the reflection plane is divided into reflection rate A and B (A>B) regions, and the reflection rates A and B are set so that each of the light intensities of the second, third and fourth emission lights Lout2 to Lout 4 respectively are the same.SELECTED DRAWING: Figure 5

Description

The present invention relates to a blind spot assisting device that projects an image in a blind spot area that is blocked by an obstacle and cannot be seen by a viewer.

For example, a driver (viewer) in a vehicle such as an automobile cannot see the scenery outside the front pillars on the left and right of the vehicle body because these front pillars block the scenery. That is, the left and right front pillars are a kind of obstacle. On the other hand, a blind spot auxiliary device that projects an image in a so-called blind spot area, which is blocked by an obstacle and cannot be seen by a viewer, is known from Japanese Patent Application Laid-Open No. 2004-242242.

The conventional blind spot auxiliary device known in Patent Document 1 has a basic configuration of a combination of a plate-shaped (planar) semi-transmissive mirror and a plate-shaped mirror arranged in parallel with each other. Conventionally, the reflectance of the semi-transmissive mirror is uniform. For example, Patent Document 1 describes that the reflectance of the semi-transmissive mirror is 50% or more and 80% or less.

JP, 2016-120833, A (paragraph [0024])

As a principle feature of the blind spot auxiliary device, the brightness decreases stepwise as the number of reflections increases. Therefore, there is an undeniable point that the display may be difficult to see due to the presence of portions of different brightness in the display.

In Patent Document 1, the reflectance of the semi-transmissive mirror is set to 50% or more and 80% or less, but even in this case, the light becomes weaker along the traveling direction of the light as the distance from the incident end of the light increases. There is room for improvement in this respect.

An object of the present invention is to provide a blind spot auxiliary device that can suppress the difference in brightness.

Other objects of the present invention will become apparent to those skilled in the art by referring to the aspects and best modes illustrated below, and the accompanying drawings.

Hereinafter, for easy understanding of the outline of the present invention, embodiments according to the present invention will be exemplified.

In the first aspect of the present invention, a blind spot auxiliary device for projecting an image of a blind spot area obstructed by an obstacle, wherein light representing the image is incident, is provided on a viewer side, and reflects a part of the light. A semi-transmissive mirror that partially transmits the light; and a mirror that faces the semi-transmissive mirror at a predetermined interval and that reflects the reflected light toward the semi-transmissive mirror. The light representing the image incident on the reflecting surface of the mirror advances in a predetermined direction while repeating reflection between the semi-transmissive mirror and the mirror, and has a structure capable of making three round trips at the maximum. As the light reaching the person's viewpoint, the first outgoing light whose number of reflections at the semi-transmissive mirror is zero, the second outgoing light whose number of reflections is 1, and the third outgoing light whose number of reflections is 2 There is emitted light and fourth emitted light having a number of reflections of 3, and the reflecting surface of the semi-transmissive mirror has a first emission corresponding to each of the first, second and third emission. , The second, and the third regions, the first to third outgoing lights are transmitted through the semi-transmissive mirror and are emitted, while the fourth outgoing light is The structure is such that the light is directly emitted without passing through the semi-transmissive mirror, and the reflectance of the reflection surface of the semi-transmissive mirror is switched at the boundary between the second region and the third region. Thus, it is divided into a region of reflectance A to which the first and second regions belong and a region of reflectance B (B<A) to which the third region belongs, and the second to second regions. The reflectances A and B are set so that the light intensities of the respective outgoing lights of No. 4 are the same (including substantially the same).

In the first mode, a structure in which reflection is repeated up to three round trips (in other words, a structure in which emitted light derived after each of three reflections in the semi-transmissive mirror and the mirror is effective light) is adopted. By appropriately switching the reflectance of the semi-transmissive mirror at a predetermined location, the second, third, and fourth outgoing lights whose reflection times at the semi-transmissive mirror are 1, 2, and 3 are reflected. The light intensity is set to be the same (including substantially the same), and the brightness of the image along the traveling direction of the light is kept as uniform as possible to reduce the discomfort.

If a large amount of light is transmitted through the semi-transmissive mirror immediately after the light is incident, the energy of the light that progresses by repeating reflection decreases, and the brightness decreases as the number of reflections increases thereafter. However, a very dark part may appear and it may look bad.

Therefore, in this aspect, the transmittance of the semi-transmissive mirror at the time of the first reflection is suppressed (that is, the reflectance is set to be large) to increase the light amount of the reflected light and propagate a large amount of energy. To In other words, the emitted light that has gone through one round trip (second emitted light) is emitted with a slightly suppressed light amount.

Regarding the emitted light (third emitted light) that has gone through two round trips in the semi-transmissive mirror, the light is emitted from a portion where the reflectance is reduced, and the light amount is increased by the amount of the reduced reflectance, thereby making the second round trip. It is possible to make the light intensity of the third outgoing light comparable to that of the second outgoing light.

In addition, the emitted light (fourth emitted light) that has gone through three round trips passes through the loss of the first round trip, the loss of the second round trip (including the increase of the propagation energy loss due to the decrease of the reflectance), and The loss at the mirror at the round trip occurs, but unlike the second and third emitted light, the fourth emitted light does not pass through the semi-transmissive mirror (in other words, is not transmitted through the semi-transmissive mirror. In addition, since it is directly emitted, the loss is saved accordingly. Therefore, by compensating for the above loss, the light intensity of the fourth emitted light can be made equal to the light intensity of the first and second emitted light.

Further, with respect to the light (first emission light) that passes through the semi-transmissive mirror without being reflected, the reflectance of the emission portion thereof is the same as the reflectance of the emission portion of the second emission light. Since the reflectance is set higher than the conventional one (that is, the transmittance is set low), the light amount of the first outgoing light is suppressed and the brightness (brightness) is reduced. That is, the brightness of the area (emission area) from which the first emission light is emitted does not become too bright. As a result, the difference in brightness from the area from which the second emitted light is emitted (emission area) is reduced. Also in this respect, the brightness is made uniform.

In order to enable such reflection involving a plurality of round trips, the reflectances A and B are switched at a predetermined position of the semi-transmissive mirror, and the reflectances A and B are set to appropriate values. Therefore, by this, a light emitting area with a small difference in brightness (in other words, a uniform brightness) is realized along the traveling direction of light, and the difference in brightness of the image of the object is reduced, It is possible to display with less discomfort. It should be noted that this is a portion where the reflectance is switched (also referred to as a boundary portion), but it can be designed with a certain width. Therefore, the term "boundary" may be broadly interpreted rather than limitedly, and the term "boundary" should be interpreted flexibly.

In a second aspect dependent on the first aspect, when the reflectance of the mirror is R, the A is set to (R+1)/(R ² +R+1) and the B is 1/( R+1) is set.

In the second aspect, the reflectivities A and B are expressed as a function of the reflectivity R of the mirror.
The intensity PW1 of the emitted light (first emitted light) that has gone through one round trip is expressed as PW1=A*R*(1-A) when the incident light is mathematically expressed as “1”. The intensity PW2 of the emitted light (second emitted light) that has gone through two round trips is expressed as PW2=A ² *R ² *(1-B). The intensity PW3 of the emitted light (third emitted light) that has gone through three round trips is expressed as PW3=A ² *R ³ *B (here, * means multiplication).

Solving the quadratic equation with PW1=PW2=PW3 yields A=(R+1)/(R ² +R+1) and B=1/(R+1). With this, the values of A and B are appropriately determined.

In a third aspect depending on the first or second aspect, a plurality of light-shielding members that are non-light-transmitting portions are provided on the viewer-side plane of the semi-transmissive mirror, and each light-shielding member is The semi-transmissive mirror is arranged so as to be inclined with an angle with respect to the normal line of the plane of the semi-transparent mirror on the viewer side so that its tip end faces the viewer side.

In the third aspect, by using the light shielding member (louver or the like), it is possible to suppress the disturbance of brightness due to the light other than the object entering and propagating inside the blind spot auxiliary device. Further, since the tip of the light-shielding member is oriented so as to face the viewer, the light-shielding member is one of the light emitted from the semi-transmissive member, which is derived in a direction not facing the viewer. In some cases, the light may be reflected by the light blocking member to change its direction to become effective light, which can be expected to have an effect of suppressing the decrease in the light amount to some extent.

Those skilled in the art will readily understand that the illustrated embodiments according to the present invention may be further modified without departing from the spirit of the present invention.

In the blind spot auxiliary device, it is possible to suppress the difference in brightness between the mirror and the semi-transmissive mirror in the area where reflection occurs. For example, in a pair of mirrors, the image becomes too bright near the end where light is incident, and conversely, the image becomes too dark near the end where the light is incident. It is possible to reduce a sense of discomfort caused by such things and improve the appearance.

(A) is a schematic view of the vicinity of a driver's seat of a vehicle equipped with a blind spot auxiliary device which is an example of the present invention, and (B) shows an appearance of another example of the blind spot auxiliary device (having a light shielding member). It is a perspective view. It is explanatory drawing of the principle of a blind spot auxiliary device. It is a perspective view showing appearance of a blind spot auxiliary device of an example of the present invention. The relative positional relationship between the semi-transmissive mirror and the mirror constituting the blind spot assisting device, which is an example of the present invention, and the formation area of the image visible to the viewer (the visible area of the image) is divided according to the number of reflections of light. FIG. 3 is a cross-sectional view taken along the traveling direction of light, showing a (divided) mode, a switching position of reflectance, and the like. FIG. 5 is a cross-sectional view along the traveling direction of light, for explaining the behavior of light with different numbers of reflections in the blind spot auxiliary device having the structure shown in FIG. 4. It is sectional drawing which shows the constructional example of the blind spot auxiliary device which provided the light shielding member (louver). It is a characteristic view which shows the measurement result about the relationship of the number of times of reciprocation (the number of times of reflection) and the display light intensity of the comparative example and the example.

The best embodiments described below are used for easy understanding of the present invention. Therefore, those skilled in the art should note that the present invention is not unduly limited by the embodiments described below.

FIG. 1(A) is a schematic view of the vicinity of a driver's seat of a vehicle equipped with a blind spot auxiliary device that is an example of the present invention, and FIG. 1(B) is an external view of another example of the blind spot auxiliary device (having a light shielding member). It is a perspective view showing. As shown in FIG. 1, the vehicle 1 includes a steering wheel 10, a windshield glass 20, side glasses 30, 40, and front pillars 50, 60. Reference numerals 21 and 22 denote light-shielding black ceramic (black ceramic) portions formed by printing around the windshield glass 20.

In the vehicle 1, the viewer (mainly the driver) directly views the landscape in the area where the windshield glass 20 (excluding the portion of the black ceramics portion 21) and the side glasses 30 and 40 are directly viewed, while the front pillar 50, In the area where 60 and the black ceramic parts 21 and 22 are arranged, the visual field of the viewer is blocked by the front pillars 50 and 60 and the black ceramic parts 21 and 22, and a blind spot area where the scenery cannot be directly viewed occurs. That is, the front pillars 50 and 60 and the black ceramic parts 21 and 22 correspond to the obstacles in the present invention.

The blind spot assisting device 100 is arranged on the right side (driver's side) front pillar 50 as viewed from the viewer side via a holder member (not shown), and displays an image of the blind spot area blocked by the front pillar 50 and the black ceramic portion 21. It is a thing. The blind spot assist device 100 is arranged so as to face the front pillar 50 and the black ceramics portion 21 when viewed from the viewer.

The blind spot assist device 100 includes a pair of parallel plane mirrors (sometimes referred to as a pair of mirrors) 110, as shown in FIG. The pair of parallel plane mirrors 110 includes a semi-transmissive plane mirror (sometimes simply referred to as a semi-transmissive mirror) 111 that reflects a part of incident light and a part of the incident light, and a plane mirror (also simply referred to as a mirror). And 112) are arranged so as to face each other in parallel. The semi-transmissive plane mirror (semi-transmissive mirror) 111 and the plane mirror (mirror) 112 are arranged in a holder member (not shown) and fixed in a parallel positional relationship. The pair of mirrors of the present invention need not be arranged in perfect parallel as long as they are arranged so as to face each other, and may be curved mirrors instead of flat mirrors. Details of the pair of parallel plane mirrors (a pair of mirrors) 110 will be described with reference to FIG.

Further, as shown in FIG. 1B, the light blocking member 120 may be provided on the viewer-side surface of the semi-transmissive flat mirror (semi-transmissive mirror) 111. The light blocking member 120 includes a light blocking portion (here, the louvers 121a to 121c). The effect of providing the light shielding member 120 will be described with reference to FIG.

Next, the principle of displaying an image of the blind spot area in the blind spot assist device 100 will be described with reference to FIG. FIG. 2 is an explanatory diagram of the principle of the blind spot assist device. In addition, in FIG. 2, reference numeral 2 indicates the viewpoint (eye point) of the viewer sitting in the driver's seat.

In the front field of view of the viewer (viewpoint 2), a blind spot area W that is blocked by the front pillar 50 (including the black ceramic portion 21 (not shown)) occurs. Therefore, the object M existing in the blind spot region W cannot be directly visually recognized from the viewpoint 2.

On the other hand, the light L from the object M enters the pair of mirrors 110 and is repeatedly reflected between the pair of mirrors 110, while part of the light L is emitted from the pair of mirrors 110 (in other words, semi-transmissive). The light is transmitted through the mirror 111 and emitted.

It is the light that is incident on the pair of mirrors 110 and repeatedly reflected between the pair of mirrors 110 is light having an inclination with respect to the parallel planes of the pair of mirrors 110. A part of the light L emitted from the pair of mirrors 110 reaches the viewpoint 2. Therefore, from the viewpoint 2, the image of the object M reflected on the plane mirror 112 can be seen through the semi-transparent plane mirror 111 continuously with the scenery directly visible. It should be noted that in the blind spot region W, in a slight region (hatched portion) on the back side of the front pillar 50, light from this region cannot enter the pair of mirrors 110, and the image thereof is projected by the pair of mirrors 110. However, the image of the blind spot region W can be projected by the pair of mirrors 110 in almost all other regions.

In displaying the image of the blind spot area W by the pair of mirrors 110, the viewer sets the blind spot auxiliary device 100 at an arbitrary height of the front pillar 50 (a height that matches the viewpoint 2) and causes the pair of mirrors 110 to blind spot. The angle of the pair of parallel plane mirrors 110 is adjusted and arranged so that the image of the region W is displayed, in other words, the light L from the blind spot region W reaches the viewpoint 2.

Since the positional relationship between the semi-transmissive mirror 111 and the mirror 112 is fixed in parallel with each other, the pair of mirrors 110 can be arranged at the same time by one arrangement work, and the pair of mirrors 110 can be arranged by one adjustment work. The angle of can be adjusted at the same time.

Since the light L is repeatedly reflected between the pair of mirrors 110, when the light L is incident on the semi-transmissive mirror 111 n times, n pieces of light L showing an image of the object M are emitted from the pair of mirrors 110. Is emitted. That is, the pair of parallel plane mirrors 110 emits the light L showing the images of the n objects M along the left-right direction of the viewpoint 2 (the left-right direction with respect to both eyes). Therefore, the viewer can visually recognize the image of the object M in a wide range in the left-right direction.

The light L emitted from the pair of mirrors 110 is reflected by the semi-transmissive mirror 111 and the mirror 112, travels in a predetermined direction (x direction shown in FIG. 2), and the number of times of reflection increases. The light intensity of the emitted light is reduced, and the brightness of the displayed image is reduced.

Next, details of the structure of the pair of mirrors 110 will be described with reference to FIG. FIG. 3 is a perspective view showing an appearance of a blind spot assisting device according to an example of the present invention.

As described above, the pair of mirrors 110 is configured by arranging the semi-transmissive mirror 111 that reflects a part of the incident light and transmits a part thereof and the mirror 112 so as to face each other in parallel. To be done. The semi-transmissive mirror 111 and the plane mirror 112 are arranged so as to have a step difference in the x direction, which is the traveling direction of the light L. The pair of mirrors of the present invention need not be arranged in perfect parallel as long as they are arranged so as to face each other, and may be curved mirrors instead of flat mirrors.

The semi-transmissive mirror 111 is disposed on the viewer side, and a metal such as aluminum is vapor-deposited on the surface of a base material made of a translucent resin material such as polyethylene terephthalate, polycarbonate, polyethylene, or acrylic to obtain a desired translucent mirror 111. A reflectance adjusting layer is formed so as to have reflectance. The reflectance (transmittance) is adjusted by the thickness and type of the reflectance adjusting layer. The semi-transmissive mirror 111 may be formed by coating the surface of a base material with a dielectric multilayer film.

The reflectance of the semi-transmissive mirror 111 of this embodiment is divided (divided) into two regions along the traveling direction of the light L at the reflectance switching boundary (boundary position) CK, and the incident side on which the light is incident. The reflectance of the region 310 is set to A, the reflectance of the region 320 on the opposite side to the incident side is set to B, and the relation of A>B is satisfied. Further, in the present embodiment, the light intensity of the transmitted light (emitted light) at a position close to the incident side is set to be smaller than in the conventional case, so that more light is propagated, and the light intensity on the side opposite to the incident side is set. A configuration different from the conventional one is adopted in that the intensity of the emitted light near the edge is suppressed and the propagated light is distributed as evenly as possible to make the overall brightness uniform. ing. Details will be described later.

The mirror 112 is arranged such that its plane (reflection surface) is parallel to the plane of the semi-transmissive mirror 111 (semi-transmissive reflection surface). For example, the base material made of the above-mentioned translucent resin material. It is a flat aluminum vapor deposition mirror made by vapor depositing metal such as aluminum on the surface of.

The respective planes (semi-transmissive reflection surface and reflection surface) of the semi-transmissive mirror 111 and the mirror 112 have a width in the direction perpendicular to the traveling direction of the light L in the pair of mirrors 110 of the light L in the pair of mirrors 110. It is formed in a substantially wedge shape so as to become gradually smaller in the traveling direction. This is because unnecessary parts outside the visual field of the viewer are removed to reduce the size and weight. Further, the semi-transmissive mirror 111 and the mirror 112 are similar in planar shape to each other (including a case where they are substantially similar), and the width of the plane mirror 112 in the direction perpendicular to the traveling direction of the light L in the pair of mirrors 110. However, the width of the semi-transmissive mirror 111 is larger than the width of the pair of mirrors 110 in the direction perpendicular to the traveling direction of the light L. When the blind spot auxiliary device 100 is viewed from diagonally below or diagonally above, a light shielding wall (not shown) (for example, which is a part of the holder member) that shields between the semi-transmissive mirror 111 and the mirror 112 in the vertical direction is reflected. This is to suppress this. The incident side end (incident side) E10 of the semi-transmissive mirror 111 and the incident side end (incident side) E11 of the mirror 112 are inclined along the glass surface of the windshield glass 20. doing. This is because it can be arranged close to the glass surface of the windshield glass 20.

Next, a suitable design example of the blind spot assist device will be described with reference to FIGS. 4 and 5. First, refer to FIG.

FIG. 4 shows the relative positional relationship between the semi-transmissive mirror and the mirror that form the blind spot assisting device, which is an example of the present invention, and the number of times the light is reflected in the area where the image is visible to the viewer (the area where the image is visible) FIG. 6 is a cross-sectional view taken along the traveling direction of light, showing a mode (division) according to the above, a switching position of reflectance, and the like. In FIG. 4, parts common to those in the above-mentioned figures are denoted by the same reference numerals (this point is the same in FIGS. 5 and 6).

The minimum and ideal configuration will be described below by omitting the design margin and the like.

A pair of mirrors 110 in plan view seen from the direction along the Z-axis are shown on the upper side of FIG. 4, and a corresponding perspective view (including a viewable region of an image by a viewer is included on the lower side of FIG. 4. )It is shown.

In addition, in the upper diagram, the design method of the pair of mirrors 110 will be described, and in the lower diagram, the visible region of the image and the switching of the reflectance will be mainly described.

In the example of FIG. 4, the semi-transmissive mirror 111 and the mirror 112 are depicted as having a rectangular and flat plate shape. The size of the semi-transmissive mirror 111 is set larger than the size of the mirror 112. That is, the semi-transmissive mirror 111 has a larger size in the length direction (X direction). The size in the width direction (Y direction) is the same in FIG. 4 (however, it is an example and is not limited to this).

As shown in the upper side of FIG. 4, the semi-transmissive mirror 111 and the mirror 112 are arranged in parallel and facing each other with a predetermined distance D therebetween. In this figure, the positions of the right ends of the semi-transmissive mirror 111 and the mirror 112 are aligned (however, the positions are not limited to this and may be different).

The semi-transmissive mirror 111 has a reflective surface (semi-transmissive reflective surface) α, and the mirror 112 has a reflective surface β.

Light representing an image incident on the reflecting surface (semi-transmissive reflecting surface) α of the semi-transmissive mirror 111 travels in a predetermined direction (here, the X direction) while repeating reflection between the semi-transmissive mirror 111 and the mirror 112, Up to 3 round trips are possible.

In the upper diagram of FIG. 4, “J1” and “J2” are the leftmost point and the rightmost point on the reflecting surface β of the mirror 112.

With the point J1 at the left end of the mirror 112 as a reference, a virtual point "J10" is taken at a distance 2D from the point J1 in the Y direction, and a virtual point "J10" is also taken at a distance 2D with respect to the point J10. The point "J20" is set, and the virtual point "J20" is set at the distance 2D with the point J10 as a reference.

The point “R1” is the leftmost point of the reflective surface α of the semi-transmissive mirror 111. The point “R2” is a point at the intersection of the reflecting surface α and the line S2 passing through the point J1 and the viewpoint 2. The point “R3” is a point at the intersection of the reflecting surface α and the line S3 passing through the point J10 and the viewpoint 2. The point “R4” is the point at the intersection of the reflecting surface α and the line S4 passing through the point J20 and the viewpoint 2.

The point "R5" is a virtual point, and when it is considered that the reflecting surface (semi-transmissive reflecting surface) α extends slightly to the right (X direction side), a line S5 passing through the point J30 and the viewpoint 2 Is the point of intersection with the extended part.

The first zone (Zone 1) is a portion having a triangular cross-section with the viewpoint 2, the point R1, and the point R2 as vertices in the space between the line S1 and the line S2. In addition, a portion having a triangular cross-section with the viewpoint 2, the point R2, and the point R3 as vertices in the space sandwiched by the line S2 and the line S3 is the second zone (Zone2). In addition, a portion having a triangular cross-section with the viewpoint 2, the point R3, and the point R4 as vertices in the space between the line S3 and the line S4 is the third zone (Zone3). Further, a portion having a triangular cross-section having the viewpoint 2, the point R4, and the point R5 as vertices in the space sandwiched by the line S4 and the line S5 is the fourth zone (Zone 4).

In addition, each of the first to fourth zones (Zones 1 to 4) emits light whose number of reflections on the semi-transmissive mirror 111 is 0, 1, 2, and 3 (for example, Lout 1 to 4 in FIG. 5 will be described later). ) Is a space divided according to. For example, the light that reaches the viewpoint 2 via the fourth zone (Zone 4) is outgoing light (for example, Lout 4 in FIG. 5) whose number of reflections by the semi-transmissive mirror 111 is 3. The specific behavior of light will be described with reference to FIG.

As shown in the lower side of FIG. 4, considering the previously described surface (surface including the virtual point R5) in which the reflective surface (semi-transmissive reflective surface) α slightly extends to the right side (X direction side), This surface corresponds to each of the first to fourth zones (Zones 1 to 4) (in other words, corresponding to each emitted light whose number of reflections is zero, 1, 2, and 3), and four regions ( The first area K1, the second area K2, the third area K3, and the fourth area K4) are divided (divided).

Here, the first to third regions K1 to K3 can be considered to be on the reflection surface (reflection/transmission surface) α. It is obvious that the fourth region K4 is not on the reflecting surface (semi-transmissive reflecting surface) α.

Here, when each of the emitted light whose number of reflections is zero, 1, 2, and 3 is referred to as first to fourth emitted light for convenience of description, the reflective surface (semitransmissive reflective surface) α of the semitransparent mirror 111 is referred to. Is divided into first to third regions K1 to K3 corresponding to the first to third zones (Zones 1 to 3), in other words, the first, second, and third emitted lights ( Can be split).

Further, in the present embodiment, as shown in the lower side of FIG. 4, the reflectance of the reflective surface (semi-transmissive reflective surface) α of the semi-transmissive mirror 111 is between the second region K2 and the third region K3. By switching at the boundary portion CK, the reflection surface (semi-transmissive reflection surface) α has a reflectance A to which the first and second regions K1 and K2 belong, and a reflectance to which the third region K3 belongs. It is substantially divided into a region 320 of B (B<A).

Then, the second to fourth emitted lights (corresponding to Lout2 to 4 in the example of FIG. 5) output from the second to fourth zones (Zone2 to Zone4) become the same (including substantially the same). As described above, the reflectances A and B are set, whereby the effect of reducing the difference between the lightness and darkness of the image and improving the appearance is obtained (this point will be described later).

Further, in order to enable reflection up to 3 round trips at maximum, the length of the mirror 112 (length along the X direction) is a line S5 and a normal line perpendicular to the reflection surface (semi-transmissive reflection surface) α. When the angle formed by is θ1, and considering that the light travels in three reciprocations, it is preferable to set it to, for example, 6 tan θ1.

On the other hand, regarding the semi-transmissive mirror 111, if the angle formed by the line S2 and the normal line perpendicular to the reflecting surface (semi-transmissive reflecting surface) α is θ2, then dtan θ2 is required in addition to the above 6 tan θ1. .. When this length is secured, at the point R1 at the left end of the semi-transmissive mirror 111, the reflected light of the light incident at the angle θ2 (denoted as La in the upper diagram of FIG. 4) is at the left end of the mirror 112. It can reach the point J1 and travel as an effective light, thus providing a suitable example.

In the drawing on the lower side of FIG. 4, line segments V1, V2, V3, V4, and V5 indicated by broken lines in the width direction are boundaries necessary to define the first to fourth regions K1 to K4. Etc., which are shown for convenience of explanation. The line segment V3 can also serve as the above-described reflectance switching boundary CK in the preferred embodiment (however, the invention is not limited to this and the vicinity thereof may be the reflectance switching boundary).

Next, refer to FIG. FIG. 5 is a cross-sectional view along the traveling direction of light, for explaining the behavior of light with different numbers of reflections in the blind spot auxiliary device having the structure shown in FIG. 5, the same parts as those in FIG. 4 are designated by the same reference numerals.

In the above description, the emitted lights corresponding to the number of reflections of zero, 1, 2, and 3 are the first to fourth emitted lights, but in FIG. 5, they are drawn as Lout1 to Lout4.

The lights that generate the outgoing lights Lout1 to Lout4 are the incident lights Lin1 to Lin4 that are incident under the most critical conditions. These incident lights are the lights that are gradually incident on the left end point J1 on the reflection surface of the mirror 112.

In FIG. 5, the locus (light ray) of the light of Lin1 is shown by the alternate long and short dash line, and this is referred to as the “first light ray”. The locus (light ray) of light corresponding to Lin2 is indicated by a thick solid line, and is referred to as a "second light ray". A locus (light ray) of light corresponding to Lin3 is indicated by a broken line, and this is referred to as a "third light ray". Further, the locus (light ray) of light corresponding to Lin4 is shown by a thin solid line, and this is referred to as a "fourth light ray".

The first light ray (dashed-dotted light ray) produces the emitted light Lout1 (in other words, the emitted light generated by passing the incident light as it is) in which the number of reflections on the reflection surface (semi-transmissive reflection surface) α is zero. Yes, this Lout1 overlaps the line S2 described above.

That is, Lout1 is located at the rightmost position on the boundary with the adjacent second zone (Zone2) among the infinite number of emitted lights that belong to the first zone (Zone1) and whose number of reflections is zero. Since it is emitted light, it is drawn by a single arrow (an alternate long and short dash line) as light representing a myriad of lights.

The same applies to the other emitted lights Lout2 to Lout4. Lout2 (thick solid line arrow) is emitted light that is emitted after being reflected once on the reflection surface (semi-transmissive reflection surface) α, and is located at the boundary with the third zone (Zone3). It will overlap the line S3.

Lout3 (broken line arrow) is emitted light that is emitted after being reflected twice on the reflection surface (semi-transmissive reflection surface) α, and is located at the boundary with the fourth zone (Zone4). It will overlap S4.

Lout4 (thin solid line arrow) is an outgoing light emitted after being reflected three times on the reflective surface (semi-transmissive reflective surface) α (however, unlike Lout1 to Lout3, directly without passing through the semi-transmissive mirror 111). To reach the viewpoint 2), which is located at the end of the fourth zone (Zone 4) on the side opposite to the third zone (Zone 3) (end of the limit). An arrow is drawn as a representative of the light that has undergone the reflection, and this overlaps the line S5.

When the left ends of the lines S3, S4, and S5 are extended, the first, second, and third parts of the object (target object) M (see FIG. 2) in the blind spot region W (parts having different locations, (Not shown).

However, the line of sight as shown by the lines S3, S4, S5 cannot actually be secured because it is blocked by an obstacle. Instead, the incident light Lin2, Lin3, Lin4, which is the light coming from the first, second, and third parts of the object (target object) M, propagates in the X direction while being reflected. Then, since the emitted lights Lout2 to 4 that overlap the lines S3, S4, and S5 are generated, the viewer sees that each part of the object (target object) M in the blind spot region W is as if the virtual points J10, J20, J30 is recognized as if it were in the previous direction along the lines S3 to S5. Therefore, the viewer can see the object (object) M at the blind spot.

As described above, the semi-transmissive mirror 111 is reflected by the reflectance switching boundary CK (which overlaps with the line segment V3 that partitions the second region K2 and the third region K3 as shown in FIG. 4). It is divided into a region 310 having a reflectance A and a region 320 having a reflectance B. The reflectances A and B have a relationship of A>B, and the values of A and B are the same (almost the same) when the light intensities of the second, third, and fourth outgoing lights Lout2, 3, and 4 are the same. Including) is set. The specific reflectance can be uniquely determined by solving the mathematical formula described later.

A qualitative explanation will be given before the explanation by mathematical expressions.

That is, if a large amount of light is transmitted by the semi-transmissive mirror 111 immediately after the light is incident, the energy of the light that proceeds by repeating reflection decreases, and the brightness increases as the number of reflections increases thereafter. It is undeniable that the appearance may be lost and the dark parts may appear, resulting in a bad appearance.

Therefore, the transmittance of the semi-transmissive mirror 111 at the time of the first reflection is suppressed (that is, the reflectance is set to be large) to increase the light amount of reflected light and propagate a large amount of energy. In other words, the emitted light that has gone through one round trip (the second emitted light Lout2) is emitted with the light amount being slightly suppressed.

Further, the emitted light (third emitted light Lout3) that has gone through two round trips in the semi-transmissive mirror 111 is emitted from a portion where the reflectance is reduced, and the light amount is increased by the amount corresponding to the reduced reflectance. By compensating for the loss at the second round trip, the light intensity of the third outgoing light Lout3 can be made approximately the same as that of the second outgoing light Lout2.

With respect to the emitted light Lout4 that has gone through three round trips, it goes through the loss of the first round trip, the loss of the second round trip (including the increase of the loss of the propagation energy due to the reduction of the reflectance), and then the mirror at the third round trip. However, unlike the second and third emitted lights (Lout2, Lout3), the fourth emitted light Lout4 does not pass through the semi-transmissive mirror 111 (in other words, transmitted through the semi-transmissive mirror 111). (Because it is not emitted), it is possible to avoid the loss because it is directly emitted. Therefore, by compensating for the above loss, the light intensity of the fourth outgoing light Lout4 can be made equal to that of the second and third outgoing lights Lout2, 3. is there.

Further, regarding the light (first emission light Lout1) that is transmitted (passes) through the semi-transmissive mirror 111 without undergoing reflection, the reflectance of the emission location (R2) is the emission location of the second emission light Lout2 ( It is the same as the reflectance of R3) (that is, A). The reflectance A is set higher than that of the conventional one. In other words, the transmittance (1-A) is set low. Therefore, the light amount of the first outgoing light Lout1 is suppressed, and the brightness (brightness) is reduced as compared with the conventional case. That is, the brightness of the area (emission area) K1 from which the first emission light Lout1 is emitted does not become too bright. As a result, the difference in brightness from the area (emission area) K2 from which the second emission light Lout2 is emitted is reduced. Also in this respect, the brightness is made uniform. These points will be described later with reference to FIG. 7.

In order to enable such a reflection involving a plurality of round trips, the reflectance at a predetermined position of the semi-transmissive mirror 111 (the position of the line segment V3 in the width direction in FIGS. 4 and 5 and the reflectance switching boundary CK). A and B are switched, and the reflectances A and B are set to appropriate values, so that there is little difference in brightness along the traveling direction of light (in other words, uniform brightness). The light emitting region is realized, and the difference in brightness of the image of the object is reduced, and display with less discomfort is possible.

Next, a description will be given using mathematical expressions. Here, the reflectance at the mirror 112 is R.

The emitted light (first emitted light Lout2) that has gone through one round trip is reflected at the point R2 of the semi-transmissive mirror 111 (reflectance A) and is reflected at a predetermined portion of the reflecting surface β of the mirror 112 (reflectance R), The light is semi-transmitted and emitted at a point R3 of the semi-transmissive mirror 111. Here, although the point R3 is located at the reflectance switching boundary position CK, the point R3 belongs to the second zone (zone2) which is a region where one round trip of light is emitted, as described above. .. Therefore, the reflectance is A. Therefore,
The transmittance is (1-A). Therefore, the intensity PW1 of the second output light Lout2 can be expressed as the following equation (1) when the incident light is mathematically expressed as “1”. Note that * represents multiplication.
PW1=A*R*(1-A)...(1)

Further, the emitted light (third emitted light Lout3) that has gone through two round trips is reflected twice by the reflecting surface (semi-transmissive reflecting surface) α of the semi-transmissive mirror 111 (twice when the reflectance A is reflected). , Is reflected twice by the reflection surface β of the mirror 112 (twice when the reflectance R is reflected), and then is transmitted and emitted at the point R4 of the semi-transmissive mirror 111. At the point R4, since the reflectance has been switched to B, the transmittance is (1-B).

Therefore, the intensity PW2 of the third output light Lout3 can be expressed as the following formula (2) when the incident light is mathematically expressed as “1”.
PW2=A ² *R ² *(1-B) (2)

The outgoing light (fourth outgoing light Lout4) that has gone through three round trips is reflected three times by the reflecting surface (semi-transmissive reflecting surface) α of the semi-transmissive mirror 111, but two times of that, the reflectance A And the other one is a reflection having a reflectance of B. Then, the light is reflected by the reflecting surface β of the mirror 112 three times (three times with the reflectance R), and the reflected light by the third reflection is directly emitted as the fourth emitted light Lout4. ..

Therefore, the intensity PW3 of the fourth output light Lout4 can be expressed as the following expression (3) when the incident light is mathematically expressed as “1”.
PW3=A ² *R ³ *B...(3)

Solving the quadratic equation with PW1=PW2=PW3 yields A=(R+1)/(R ² +R+1) and B=1/(R+1). With this, the values of A and B are appropriately determined.

For example, when R is 90%, A is 70% and B is 53%. However, although this is the most preferable value, it may be slightly deviated for design reasons. Such a case is also included in the scope of the technical idea of the present invention.

It should be noted that in the above description, only reflection and transmission at the semi-transmissive mirror 111 and reflection at the mirror 112 are considered. Actually, the precision may be improved by adding more detailed parameters or information of additional parts, but since it becomes complicated, the description here is limited to the basic idea that occupies a large number.

As described above, the reflectance of the semi-transmissive mirror 111 is divided at the boundary between the second zone (Zone 2) and the third zone (Zone 3), and the reflectances are individually set so that the second to second It is possible to make the display brightness in each of the fourth zones (Zone 2 to Zone 4) uniform (constant, substantially constant). Further, the difference in display brightness between the first zone (Zone 1) and the second zone (Zone 2) (brightness (luminance) between the first region K1 and the second region K2 in the lower diagram of FIG. 4) The difference) can be reduced, and also in this respect, the brightness of the image in the X direction, which is the traveling direction of light, can be made uniform.

Next, the structure including the light shielding member will be described with reference to FIG. FIG. 6 is a cross-sectional view showing a structural example of a blind spot auxiliary device provided with a light shielding member (louver).

In FIG. 6, a plurality of light-shielding members (louvers) 121a to 121c, which are non-light-transmitting portions, are provided on the plane H on the viewer side of the semi-transmissive mirror 111, and each light-shielding member 121a to 121c is A structure in which the semi-transparent mirror 111 is inclined and arranged at an angle with respect to the normal line of the plane H on the viewer side of the semi-transmissive mirror 111 so that its tip portion faces the viewer side is adopted. The louvers 121a, 121b, 121c are arranged in accordance with the first zone (Zone1) to the third zone (Zone3), in other words, along the lines S1, S2, S3 described above, and The structure is fixed in contact with the lower surface of the semi-transmissive mirror 111 (a plane on the viewer side opposite to the reflection surface).

By using the light shielding members 121a to 121c, the disturbance of the brightness due to the light (light N1 in FIG. 7) other than the object entering and propagating inside the blind spot auxiliary device 100 (the pair of mirrors 110) is prevented. Can be suppressed.

Further, since the tip ends of the light shielding members 121a to 121c are oriented so as to face the viewer, the light emitted from the semi-transmissive member 111 is led out in the direction not facing the viewer. Even if there is light (light N2 in FIG. 7), the light may be reflected by the light blocking member (louver 121a in FIG. 7) to change its direction to become effective light. The effect of suppressing the decrease in the amount of light can be expected to some extent.

Next, the effect of the present invention will be described with reference to FIG. FIG. 7 is a characteristic diagram showing the measurement results of the relationship between the number of round trips (the number of reflections) and the display light intensity in the comparative example and the example.

In FIG. 7, P1 to P4 show characteristics of a comparative example, and Q1 to Q4 show characteristics of an embodiment of the present invention (for example, an embodiment relating to the structure of FIG. 6). Here, it is assumed that the characteristic is display light intensity.

Comparing the characteristics P1 and Q1 corresponding to the region (section) where the number of reflections is zero, the embodiment has a lower numerical value than the comparative example. That is, in the present embodiment, unlike the comparative example, the brightness does not become too bright, and the brightness is slightly suppressed.

Next, focusing on the characteristic Q2 in one round trip section of the present embodiment, the difference from the characteristic Q1 in the section in which the number of reflections is zero is small, and the brightness is made uniform. In the case of the comparative example, the difference between the characteristics P1 and P2 may be large, and the difference in brightness may feel unnatural. In the case of the embodiment, such a possibility is small.

In addition, in the case of the embodiment, it can be seen that there is almost no difference between the characteristics Q2 to Q4 in each of the 1 round trip, 2 round trip, and 3 round trip, and uniform brightness is realized. On the other hand, in the comparative example, the difference between P2 and P3 is large, and the numerical values of P2, P3, and P4 are not the same and are different. Therefore, it is undeniable that it may cause discomfort.

Therefore, according to the present invention, even if the number of reflections increases, the light intensity does not decrease, and uniform brightness can be maintained throughout.

The present invention is not limited to the above embodiment and drawings. Needless to say, changes (including deletion of components) can be added to the above-described embodiment and drawings.

Although the blind spot auxiliary device 100 of the present embodiment is arranged on the front pillar 50 on the right side when viewed from the driver's seat side of the vehicle 1, the same blind spot auxiliary device is also arranged on the front pillar 60 on the left side. Good. Further, as an obstacle in the vehicle, a blind spot auxiliary device may be arranged in the center pillar, the rear pillar, or the like other than the front pillar and project an image of a blind spot area blocked by these.

Further, the present invention can be widely applied to fields other than vehicles as a blind spot auxiliary device that projects an image of a blind spot area blocked by an obstacle. For example, when the blind spot auxiliary device of the present invention is used in a house, a large area blind spot auxiliary device is attached to the ceiling and only the incident part is exposed to the outside from a wall or the like so that the blind spot auxiliary device on the ceiling is empty while staying indoors. You can also see the sunlight and guide sunlight from the ceiling indoors. It is particularly suitable for densely-built houses or houses where there is a situation where ordinary windows cannot be installed.

Also, for example, in a high-rise building such as a tourist facility, by embedding a large-area blind spot auxiliary device under the floor on the higher floors and exposing only the light incident part to the outside, the blind spot auxiliary device under the floor can bring the scenery below directly under your feet. You can feel it, and you can emphasize the height of the building. In order to obtain the same effect, it was conventionally necessary to provide a space under the floor, but the blind spot auxiliary device of the present invention is suitable because it can be easily arranged in an existing building.

In addition, as an example of use for a wall surface, at a crossing where the fence stands close to a road and has poor visibility, the blind spot assisting device of the present invention is arranged at the corner of the fence so that pedestrians and vehicles in the blind spot area Being able to quickly recognize the existence of a person and contribute to the prevention of encounter accidents.

As described above, the blind spot assist device of the present invention does not require energy such as electric power, and does not require energy such as electric power. It can be viewed with a uniform brightness over a wide range in the left-right direction with both eyes as a reference, and its application can be widely applied both indoors and outdoors to obtain various effects such as health, safety, and emotion. be able to.

The present invention is not limited to the above-described exemplary embodiments, and those skilled in the art can easily modify the above-described exemplary embodiments to the scope included in the claims. ..

DESCRIPTION OF SYMBOLS 1... Vehicle, 2... Viewpoint, 100... Blind spot auxiliary device, 110... A pair of mirrors (a pair of parallel plane mirrors), 111... Semi-transmission mirror (semi-transmission plane mirror), 112 ... Mirrors (flat mirrors), 120 (121a to 121c)... Light-shielding members (louvers), 310... Regions of reflectance A in the semi-transmissive mirror, 320... Reflectance B in the semi-transmissive mirror Region, W... Blind spot region, M... Object (object) existing in the blind spot region, CK... Reflectance switching position (switching boundary, switching region)

Claims (3)

A blind spot auxiliary device for projecting an image of a blind spot area blocked by an obstacle,
Light representing the image is incident, provided on the viewer side, a semi-transmissive mirror that reflects a part of the light and transmits a part of the light,
A mirror that is arranged to face the semi-transmissive mirror at a predetermined interval, and that reflects the reflected light toward the semi-transmissive mirror,
Equipped with
Light representing the image that has entered the reflecting surface of the semi-transmissive mirror travels in a predetermined direction while repeating reflection between the semi-transmissive mirror and the mirror, and has a structure capable of making three round trips at the maximum. ,
As the light reaching the viewpoint of the viewer, the first emitted light whose number of reflections by the semi-transmissive mirror is zero, the second emitted light whose number of reflections is 1, and the number of reflections which is 2 And the fourth emitted light having the number of reflections of 3, and the reflecting surface of the semi-transmissive mirror is
It can be divided into first, second, and third regions corresponding to the first, second, and third emitted lights,
Each of the first to third outgoing light is transmitted through the semi-transmissive mirror and is emitted, while the fourth outgoing light is directly emitted without passing through the semi-transmissive mirror. Yes,
The reflectance of the reflection surface of the semi-transmissive mirror is switched at the boundary between the second region and the third region, so that the reflectance A to which the first and second regions belong A region and a region of reflectance B (B<A) to which the third region belongs,
The reflectances A and B are set such that the light intensities of the second, third, and fourth emitted lights are the same (including substantially the same). Auxiliary device. When the reflectance of the mirror is R,
The A is set to (R+1)/(R ² +R+1),
The blind spot auxiliary device according to claim 1, wherein the B is set to 1/(R+1). A plurality of light-shielding members, which are non-light-transmitting portions, are provided on the viewer-side plane of the semi-transmissive mirror, and each light-shielding member has a semi-transparent member such that its tip end faces the viewer. The blind spot auxiliary device according to claim 1 or 2, wherein the transparent mirror is arranged at an angle with respect to a normal line of the plane on the viewer side of the transmission mirror.

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