JP2004136762A - Inner mirror - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inner mirror causing no hindrance to direct visibility of a vehicle driver, imparting no psychological sense of oppression to the vehicle driver by the presence of a monitor, and monitoring the vehicle driver even at night and in a tunnel. <P>SOLUTION: In this inner mirror 10, when the light having a wave length of an infrared light area irradiated toward the front side of a filter 26 from an infrared LED 24 arranged inside a housing 12 on the reverse side of the filter 26 is made incident on the filter 26 from the reverse side, the infrared light having a wave length outside of a range X is reflected, and the infrared light having the wave length in the range X is made incident on the filter 26 from the reverse side, and passes to the front side. The infrared light having the wave length in the range X passing through the filter 26 is irradiated to the vehicle driver. The infrared light having the wave length in the range X reflected by the vehicle driver is also made incident on the filter 26 from the front side, and passes again to the reverse side, and is made incident on a lens 22 of an infrared camera 20 having the optical axis turning to the front side of the filter 26. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inner mirror applied to a vehicle or the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known a monitoring apparatus that captures a vehicle driver, processes the obtained image, and detects the driver's dozing state, inattentive state, and the like (for example, see Patent Literature 1). Patent Literature 1 discloses a technology in which a light emitting element and a CCD image pickup element are provided in the upper left corner of a passenger seat in a vehicle interior, and a three-dimensional position of the driver is detected from an image obtained by photographing the driver of the vehicle. I have.
[0003]
However, if a monitoring device is provided in the upper left corner of the passenger seat in the passenger compartment, the camera position must be given to the driver every time in order to always photograph the vehicle driver regardless of the physique and seat position of the vehicle driver. It is necessary to adjust them together or to widen the angle of view of the imaging lens. Adjusting the camera position each time is complicated, and there is a possibility that the driver cannot be photographed accurately. Also, if the angle of view of the imaging lens is widened, the image area of the driver's eyes becomes relatively small, making it difficult to determine the driver's line of sight and to determine whether the driver's eyes are open or closed. There was a problem.
[0004]
For this reason, there is a vehicle in which a CCD camera, an infrared LED, and the like are provided in addition to an inner mirror of a vehicle (for example, see Patent Document 2).
[0005]
According to the inner mirror disclosed in Patent Document 2, a CCD camera is provided inside the inner mirror, and an infrared LED is provided outside the inner mirror so that the CCD camera is automatically adjusted when a driver sits on a seat and adjusts the inner mirror. Is adjusted. Accordingly, the driver can be reliably photographed regardless of the physique and the seat position of the driver, so that the subsequent image processing is facilitated, and the state of the driver can be detected with high accuracy. Further, by irradiating light other than visible light, for example, infrared light, the driver can be photographed even at night or in a tunnel.
[0006]
However, in the inner mirror disclosed in Patent Literature 2, the light emitting portion is protruded outside the inner mirror, and the projection area of the front portion of the inner mirror is large, so that not only the appearance is poor, but also the appearance is poor. It also impairs the driver's direct view. Further, if the driver becomes aware of the presence of the monitoring device, the driver may be in a state of being monitored and may feel psychologically oppressive.
[0007]
[Patent Document 1]
JP-A-60-168004 [Patent Document 2]
JP-A-11-331653
[Problems to be solved by the invention]
In consideration of the above facts, the present invention does not obstruct the direct view of the vehicle driver, and does not give a feeling of psychological oppression to the vehicle driver due to the presence of the monitoring device, and at night or in a tunnel. It is another object of the present invention to provide an inner mirror capable of monitoring a vehicle driver.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, an inner mirror according to the first aspect of the present invention is provided over the entire surface on the opening side of the housing, reflects light having a wavelength in the visible light region incident from at least the front side, and A filter that transmits light of a wavelength in the infrared light region incident from the side and the back side, and an imaging device that is provided inside the housing on the back side of the filter and has an optical axis facing the front side of the filter. A light-emitting unit that is provided inside the housing on the back side of the filter and irradiates light having a wavelength in the infrared light region toward the front side of the filter.
[0010]
In the inner mirror according to the first aspect, light having a wavelength in the visible light region that is incident from at least the front side of the filter is reflected. For example, if the front side of the filter is directed toward the vehicle driver, the vehicle driver can confirm the rear by light having a wavelength in the visible light region that is incident on the filter from the front side and reflected.
[0011]
In addition, light having a wavelength in the infrared region irradiated toward the front side of the filter from the light emitting portion provided inside the housing on the back side of the filter enters the filter from the back side and transmits to the front side. I do. The light of the wavelength in the infrared region transmitted through the filter is irradiated to the vehicle driver, and the reflected light of the wavelength in the infrared region reflected by the vehicle driver is incident on the filter from the front side and the back side. Again, and is incident on an imaging device whose optical axis is directed to the front side of the filter. That is, even if the light emitting unit is provided together with the imaging device inside the housing on the back side of the filter, light of the wavelength in the infrared light region emitted from the light emitting unit passes through the filter, and the vehicle driver emits infrared light. Can be monitored. Thus, the projected area of the front surface of the inner mirror can be made the same size as a normal inner mirror, and the existence of the monitoring device is hard to be recognized from the outside of the inner mirror.
[0012]
As described above, the inner mirror according to the first aspect does not obstruct the direct view of the vehicle driver, does not give the vehicle driver a feeling of psychological oppression due to the presence of the monitoring device, and furthermore, does not require nighttime or It is possible to monitor a vehicle driver even in a tunnel or the like.
[0013]
An inner mirror according to a second aspect of the present invention is the inner mirror according to the first aspect, wherein light having a wavelength in the infrared light region transmitted by the filter is limited to a predetermined range corresponding to the imaging device. It is characterized by
[0014]
In the inner mirror according to the second aspect, of the light of the wavelength in the infrared light range irradiated from the light emitting unit, the light of the wavelength in the infrared light range limited to a predetermined range corresponding to the imaging device filters the filter. To Penetrate. That is, since light having a wavelength in the infrared region that passes through the filter and enters the imaging device is limited by the filter to a predetermined range corresponding to the imaging device, the filter serving as a reflecting mirror is It also serves as a cut filter that eliminates light of wavelengths that do not correspond to. As a result, unnecessary light (so-called “disturbance”) that is not suitable for the imaging device and is included in various lights (sunlight, light from oncoming vehicles, etc.) emitted to the driving vehicle driver is captured. Since the light is prevented from being incident on the device, a stable image with little influence of disturbance can be obtained by the imaging device, and the contrast is remarkably exhibited.
[0015]
As described above, in the inner mirror according to the second aspect of the present invention, the image obtained by photographing the vehicle driver becomes clear (particularly, a stable image less affected by disturbance, The contrast can be noticeable) and the image can be analyzed more accurately, thus improving the performance of the monitoring device.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is an exploded perspective view showing an inner mirror 10 according to an embodiment of the present invention.
[0017]
As shown in FIG. 1, the inner mirror 10 includes a housing 12. The housing 12 has a substantially rectangular dish shape having a bottom wall and a peripheral wall, and has an open front side (the arrow A side in FIG. 1).
[0018]
A stay 14 is provided at the longitudinal center of the bottom wall of the housing 12 on the back side (the side opposite to the arrow A in FIG. 1). The stay 12 fixes the housing 12 to a ceiling or the like in the vehicle interior.
[0019]
A substantially rectangular flat plate-shaped substrate 16 is provided in the opening of the housing 12. The board 16 is fitted into the opening of the housing 12 and is supported by a support member protruding inside the housing. The back side of the substrate 16 is covered with the housing 12.
[0020]
A through hole 18 is provided on one side of the substrate 16 in the longitudinal direction (the right side in FIG. 1). The through-hole portion 18 is a circular hole through which the substrate 16 penetrates in the thickness direction.
[0021]
An infrared camera 20 serving as an imaging device is provided on the back side of the substrate 16. The infrared camera 20 is covered with the housing 12 and the substrate 16 and is inside the housing 12.
[0022]
The infrared camera 20 has a lens 22, and the lens 22 is concentric with the through hole 18. The lens 22 is exposed to the front side from the through hole 18 so that the optical axis of the lens 22 faces the front side of the substrate 16.
[0023]
On the front side of the substrate 16, infrared LEDs 24 are provided on both sides of the through hole 18 in the longitudinal direction of the substrate 16. The infrared LED 24 is a light emitting unit and emits infrared light toward the front side. The infrared LED 24 enables shooting at night or in a tunnel.
[0024]
A substantially rectangular flat filter 26 is provided on the front side of the substrate 16. The filter 26 covers the front side of the substrate 16 and the infrared LED 24. The infrared LED 24 is inside the housing 12 on the rear side of the filter 26.
[0025]
FIG. 2 is a graph showing a change in the reflectance R and the transmittance T of the filter 26 included in the inner mirror 10 according to the present embodiment when the wavelength of the irradiation light is changed. Indicates the transmittance T, and the dashed line indicates the reflectance R.
[0026]
As shown in FIG. 2, the spectral characteristic of the filter 26 is such that the reflectance R of light having a wavelength in the visible light region Y is high (the transmittance T is low). In the infrared light region Z, the transmittance T of infrared light having a wavelength in the range X corresponding to the infrared camera 20 (specifically, light having a wavelength in the range of 850 nm to 950 nm) is high (reflectance). R is low), and the reflectance R of infrared light having a wavelength outside the range X is high (the transmittance T is low). That is, light transmitted through the filter 26 is limited to infrared light having a wavelength within the range X corresponding to the infrared camera 20.
[0027]
A cover 28 is provided on the front side of the filter 26. The cover 28 has a substantially rectangular shape having a bottom wall and a peripheral wall. The cover 28 has a frame shape in which a central portion of the bottom wall is partially opened, and is fixed to an opening edge of the housing 12. The outer edge of the filter 26 is held by the cover 28, and the front side of the filter 26 is exposed from the opening of the cover 28.
[0028]
Next, the operation of the present embodiment will be described.
[0029]
In the inner mirror 10 having the above configuration, light having a wavelength in the visible light region incident on the filter 26 is reflected. For example, if the front side of the filter 26 is directed toward the vehicle driver, the vehicle driver can confirm the rear by light having a wavelength in the visible light region that is incident on the filter 26 from the front side and reflected.
[0030]
Further, when light having a wavelength in the infrared region irradiated from the infrared LED 24 provided inside the housing 12 on the back side of the filter 26 toward the front side of the filter 26 enters the filter 26 from the back side, The infrared light having a wavelength outside the range X is reflected, and the infrared light having a wavelength within the range X is incident on the filter 26 from the back side and is transmitted to the front side. The infrared light having a wavelength within the range X transmitted through the filter 26 is irradiated to the vehicle driver, and the infrared light having a wavelength within the range X reflected by the vehicle driver enters the filter 26 from the front side. Then, the light is transmitted again to the back side, and enters the lens 22 of the infrared camera 20 whose optical axis is directed to the front side of the filter 26.
[0031]
That is, even if the infrared LED 24 is provided together with the infrared camera 20 inside the housing 12 on the back surface side of the filter 26, the light corresponding to the infrared camera 20 in the light of the wavelength in the infrared light region emitted from the infrared LED 24. The transmission of the infrared light having the wavelength within X through the filter 26 allows the vehicle driver to be monitored by the infrared light. Thereby, the projection area of the front part of the inner mirror 10 can be made the same size as a normal inner mirror, and it is difficult for the outside to know the existence of the infrared camera 20 and the infrared LED 24.
[0032]
As described above, the inner mirror 10 having the above-described configuration does not hinder the direct view of the vehicle driver, and the presence of the infrared camera 20 and the infrared LED 24 serving as the monitoring device makes the vehicle driver feel psychologically oppressive. , And it is possible to monitor the vehicle driver even at night or in a tunnel.
[0033]
Furthermore, since only infrared light having a wavelength within the range X corresponding to the infrared camera 20 is incident on the infrared camera 20, the filter 26 serving as a reflecting mirror excludes light having a wavelength not corresponding to the infrared camera 20. Also serves as a cut filter. As a result, unnecessary light (so-called “disturbance”) that is not suitable for the infrared camera 20 and is included in various lights (sunlight, light of lights of oncoming vehicles, etc.) emitted to the driver of the driving vehicle, Since the light is prevented from being incident on the infrared camera 20, the infrared camera 20 can obtain a stable image with little influence of disturbance, and the contrast is remarkably exhibited.
[0034]
As described above, in the inner mirror 10, the image obtained by photographing the vehicle driver becomes clear (particularly, a stable image less affected by disturbance, and the contrast is remarkable) by the filter 26 which also functions as a cut filter. ), And the image is analyzed more accurately, thereby improving the performance as a monitoring device.
[0035]
Note that the present invention is not limited to the above-described embodiment, and various forms are possible. For example, in the above embodiment, the infrared camera 20 and the infrared LED 24 are provided on the right side of the substrate 16 in FIG. 1, but this is based on the assumption of a right-hand drive vehicle. The present invention is not limited to this, and in the case of a left-hand drive vehicle, it is preferable that an infrared camera and an infrared LED are provided on the left side of the board.
[0036]
【The invention's effect】
As described above, according to the inner mirror of the present invention, the direct view of the vehicle driver is not obstructed, and the presence of the monitoring device does not give the vehicle driver a feeling of psychological oppression, and It is possible to monitor a vehicle driver even at night or in a tunnel.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing an inner mirror according to the present embodiment.
FIG. 2 is a diagram showing a change characteristic of a reflectance and a transmittance of a filter constituting an inner mirror according to the present embodiment.
[Explanation of symbols]
10 inner mirror 12 housing 20 infrared camera (imaging device)
24 infrared LED (light emitting unit)
26 Filter

Claims (2)

A filter that is provided over the entire surface on the opening side of the housing and reflects at least light having a wavelength in the visible light region incident from the front side and transmitting light having a wavelength in the infrared light region incident from the front side and the back side. When,
An imaging device provided inside the housing on the back side of the filter and having an optical axis facing the front side of the filter,
A light-emitting unit that is provided inside the housing on the back side of the filter and irradiates light having a wavelength in the infrared light region toward the front side of the filter,
An inner mirror comprising: The inner mirror according to claim 1, wherein light having a wavelength in the infrared light region transmitted by the filter is limited to a predetermined range corresponding to the imaging device.

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