Electronic rearview mirror with light sensor

Abstract

The utility model relates to an electronic rearview mirror with a light sensor, which comprises an electric control reflecting screen, a protective lens and the light sensor, the protective lens is arranged on the front side of the electric control reflecting screen, and a circle of shielding layer is arranged on the edge of the rear side surface of the protective lens; the light sensor is integrated in the rear side area of the shielding layer; the optical film is characterized in that the shielding layer is a semi-reflecting film, and the semi-reflecting film is a multi-layer optical film formed by overlapping a plurality of layers of optical medium films with different refractive indexes. According to the electronic rearview mirror, the integrity and the aesthetic quality of the appearance of a product can be remarkably improved, and the shielding layer is easy to have consistent reflectivity and transmittance during batch production, so that the stability of the anti-dazzling performance of the product is ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of automobile rearview mirror, concretely relates to an electronic rearview mirror with light sensor. BACKGROUND

[0002] The electronic rearview mirror is a rearview mirror that can control its mirror reflectivity through a circuit, which generally relies on the built-in light sensor and the electrically controlled reflective screen to work together to achieve the anti-dazzling function. Specifically, the light sensor can monitor the light intensity parameters of the rear light source (such as the high beam intensity of the rear vehicle) in real time, dynamically adjust the reflectivity of the electrically controlled reflective screen through a closed-loop control system, effectively suppress strong light interference, and thus improve the safety of driving.

[0003] In order to shield the peripheral circuit of the electrically controlled reflective screen, the existing electronic rearview mirror usually sets a protective lens on the front side of the electrically controlled reflective screen and sets a metal coating layer on the rear side edge of the protective lens to form a shielding layer. This design can make the edge area of the electronic rearview mirror and the central mirror present a uniform color, thereby significantly improving the overall appearance of the product. However, this electronic rearview mirror needs to open a light-transmitting hole in the metal coating layer so that light can penetrate to the light sensor, resulting in a visual breakpoint in the shielding layer, which destroys the appearance consistency of the product.

[0004] Although some people have proposed reducing the thickness of the metal coating layer to form a metal semi-transparent film as a shielding layer in the edge area of the electronic rearview mirror and placing the light sensor behind the metal semi-transparent film to avoid the technical solution of opening a hole in the shielding layer, the light transmittance of the metal semi-transparent film is extremely sensitive to nanometer-level changes in the film thickness, so it cannot ensure the consistency of the light transmittance during mass production. Such non-uniform light transmittance shielding layer directly affects the sensitivity stability of the light sensor, causing fluctuations in its anti-dazzling performance, so it does not have practical application value. SUMMARY

[0005] The technical problem to be solved by the utility model is to provide an electronic rearview mirror with a light sensor, which can significantly improve the overall appearance and aesthetic quality of the product, and the shielding layer can easily ensure consistent reflectivity and transmittance during mass production, which is beneficial to ensuring the stability of the anti-dazzling performance of the product. The technical scheme adopted is as follows:

[0006] An electronic rearview mirror with a light sensor, comprising an electrically controlled reflective screen, a protective lens, and a light sensor, the protective lens is arranged on the front side of the electrically controlled reflective screen, and a shielding layer is arranged on the rear side edge of the protective lens; the light sensor is integrated in the rear side area of the shielding layer; characterized in that: the shielding layer is a semi-reflective film, and the semi-reflective film is a multi-layer optical film composed of multiple layers of optical medium films with different refractive indexes.

[0007] The above-mentioned shielding layer is a semi-reflective film, which is a multilayer optical film composed of multiple layers of optical medium films with different refractive indexes, has a low film thickness uniformity requirement (significantly lower than the nanoscale control of the semi-transparent metal film), and can be precisely controlled in transmittance and reflectance by adjusting the structure parameters of each film layer to form a semi-reflective film with specific transmittance / reflectance characteristics. Moreover, in the batch production of the shielding layer, the multilayer optical film has more consistent reflectance and transmittance at each location compared to the metal plating film layer. This feature can ensure the consistency of the reflectance of the batch-produced shielding layer, which shields before the light sensor and does not affect the consistency of the sensitivity of the product light sensor (the consistency error of the sensitivity of each light sensor of the same batch of products is not more than 5%), thereby meeting the response accuracy requirement in the vehicle-mounted environment and being conducive to ensuring the stability of the anti-dazzling performance, and having practical application value.

[0008] In the structure of the above-mentioned electronic rearview mirror, the driving circuit of the electrically-controlled reflective screen is arranged in the periphery of the display area, and the central area is an optical control function area; the shielding layer is arranged on the edge portion of the rear side of the protective lens and is mainly used for shielding the driving circuit of the electrically-controlled reflective screen, and can realize a mirror surface luster effect that the edge area and the middle area are completely matched; the shielding layer is a semi-reflective film, and the light sensor is integrated in the rear side area of the shielding layer and is shielded by the shielding layer, so that the light of the rear light source can directly pass through the semi-reflective film to reach the light sensor. When the light sensor detects that the light intensity exceeds 2000 lux, the control circuit automatically increases the driving voltage of the electrically-controlled reflective screen to reduce the reflectance to below 15% to realize the anti-dazzling function. Therefore, no hole needs to be opened in the shielding layer, and the visual fragmentation in the traditional structure is eliminated. Moreover, through the synergistic effect of the mirror surface reflection and the hiding of the functional elements, the overall integrity and aesthetic quality of the appearance of the product are significantly improved.

[0009] As a preferred scheme of the present application, the shielding layer comprises multiple layers of high-refractive-index medium films and multiple layers of low-refractive-index medium films, and each layer of high-refractive-index medium film and each layer of low-refractive-index medium film are arranged alternately from front to back.

[0010] The high-refractive-index medium film has a refractive index of 1.8-2.7, and the specific film layer material can be TiO2, Ti3O5, Nb2O5, Ta2O5, etc. The low-refractive-index medium film has a refractive index of 1.3-1.6, and the specific film layer material can be MgF2, SiO2, etc.

[0011] As a further preferred scheme of the present application, the high-refractive-index medium film is made of titanium dioxide (TiO2) and has a refractive index of 2.4; and the low-refractive-index medium film is made of silicon dioxide (SiO2) and has a refractive index of 1.46. In this way, the overall reflectance difference of the mirror surface of the electronic rearview mirror is less than 2%, and the mirror surface effect of the whole silver-gray color is presented visually.

[0012] As a further preferred scheme of the utility model, the optical thickness of the high refractive index dielectric film and the low refractive index dielectric film is λ / 4.The shielding layer adopts the distributed Bragg reflector (DBR) structure formed by multiple layers of optical dielectric film with different refractive index of λ / 4 optical thickness, which can be prepared by magnetron sputtering process, and the thickness tolerance of each film layer can be controlled within ±8%, and the standard deviation of transmittance is less than 1.5% in batch production, and the light is semi-transmissive / semi-reflective by the control of the optical thickness of λ / 4 wavelength order (the reflectivity of 45%±3% and the transmittance of 55%±3% are realized in the visible light band), and the characteristics of the semi-reflective film are mainly determined by the number of film layers and the refractive index difference.

[0013] As a preferred scheme of the utility model, the protective lens and the shielding layer are adhered on the front side of the electrically controlled reflective screen by the adhesive layer.

[0014] As a preferred scheme of the utility model, the electrically controlled reflective screen adopts the liquid crystal light valve structure, which comprises a liquid crystal cell, a polarizing plate and a reflective layer, the polarizing plate is attached to the front side of the liquid crystal cell, and the reflective layer is arranged on the back side of the liquid crystal cell.

[0015] As a further preferred scheme of the utility model, the liquid crystal cell comprises a first transparent plate, a second transparent plate and a liquid crystal layer, the liquid crystal layer is arranged between the first transparent plate and the second transparent plate, and is composed of nematic liquid crystal, the first transparent plate is provided with a first transparent electrode and a first alignment layer on the side close to the liquid crystal layer, and the second transparent plate is provided with a second transparent electrode and a second alignment layer on the side close to the liquid crystal layer. In the reflective mode, the deflection angle of the liquid crystal molecules in the liquid crystal layer changes linearly with the driving voltage in the range of 0-5V, and the reflectivity is dynamically adjusted from 45% to 8%, so that the dynamic adjustment of the reflective brightness can be realized by adjusting the deflection angle of the liquid crystal molecules.

[0016] As a further preferred scheme of the utility model, the reflective layer adopts a reflective polarizing film (such as 3M RPM reflective polarizing film).

[0017] The above-mentioned electrically controlled reflective screen can also adopt an electrochromic (EC) light valve structure, which is based on the ion migration effect of electrochromic material (such as WO2 / NiO) to control the reflection intensity by voltage, and the reflectivity of the rearview mirror can be directly controlled by the electrochromic layer.

[0018] As a preferred scheme of the utility model, the light sensor adopts an infrared sensor. Thus, the interference of the visible light band on the light sensor can be effectively eliminated.

[0019] As another preferred scheme of the utility model, the light sensor is composed of a photodiode or a photoresistor.

[0020] The light ray sensor can also adopt a multi-channel optical detection assembly for monitoring the brightness change of the rear light source in real time and feeding back signals to the control system to realize dynamic anti-dazzling adjustment through the electrically-controlled reflecting screen.

[0021] The electronic rearview mirror can be expanded to a streaming media rearview mirror to realize dual modes of reflecting function and image display. As a preferred scheme of the present application, the rear side of the electrically-controlled reflecting screen is provided with a display screen.

[0022] As a further preferred scheme of the present application, the electronic rearview mirror further comprises a shell, the front side of the shell has an opening, the electrically-controlled reflecting screen and the display screen are both installed in the inner cavity of the shell, and the protective lens is installed at the opening of the shell.

[0023] Compared with the prior art, the present application has the following advantages:

[0024] (1) The shielding layer in the electronic rearview mirror is used for shielding the driving circuit of the electrically-controlled reflecting screen, and the light ray sensor is integrated in the rear side area of the shielding layer, the shielding layer is a semi-reflective film, the light rays of the rear light source can directly penetrate the semi-reflective film to reach the light ray sensor, the edge area and the middle area of the light ray sensor can be completely matched to realize a mirror surface luster effect, thus there is no need to open a hole in the shielding layer, the visual fragmentation in the traditional structure is eliminated, and through the synergistic effect of the mirror surface reflection and the functional element hiding, the overall integrity and aesthetic quality of the product appearance can be significantly improved.

[0025] (2) The shielding layer in the electronic rearview mirror is a semi-reflective film, which is a multi-layer optical film composed of multiple layers of optical medium films with different refractive indexes, the film thickness uniformity requirement of the semi-reflective film is lower than that of the metal coating layer (significantly lower than the nanometer-level control of the semi-transparent metal film), and the reflectivity and transmittance of the semi-reflective film are more consistent, this feature can ensure that the reflectivity of the shielding layer is consistent in batch production, the shielding layer shields in front of the light ray sensor and does not affect the sensitivity consistency of the product light ray sensor (the sensitivity consistency error of each light ray sensor of the same batch of products is not more than 5%), meets the response accuracy requirement in the vehicle-mounted environment, is conducive to ensuring the stability of the anti-dazzling performance, and has practical application value. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a structural schematic view of the electronic rearview mirror of the preferred embodiment of the present application.

[0027] Figure 2 isFigure 1 An exploded view of the electronic rearview mirror.

[0028] Figure 3 is Figure 1 A cross-sectional view of the interior of the electronic rearview mirror (with the housing not drawn).

[0029] Figure 4 is Figure 1 A cross-sectional view of the obscuration layer in the electronic rearview mirror. DETAILED DESCRIPTION

[0030] As Figures 1-4 shown, the electronic rearview mirror with light sensor includes a housing 1, an electrically controlled reflective screen 2, a protective lens 3, and a light sensor 4. The front side of the housing 1 has an opening 101. The electrically controlled reflective screen 2 is installed in the inner cavity of the housing 1. The protective lens 3 is installed at the opening 101 of the housing 1 and is located in front of the electrically controlled reflective screen 2. A ring of obscuration layer 5 is provided at the rear side edge of the protective lens 3. The obscuration layer 5 is a semi-reflective film, which is a multi-layer optical film composed of multiple layers of optical medium films with high and low refractive indexes. The light sensor 4 is integrated in the rear side area of the obscuration layer 5.

[0031] In this electronic rearview mirror, the drive circuit of the electrically controlled reflective screen 2 is arranged in the periphery of the display area, and the central area is an optical control function area. The obscuration layer 5 is provided on the rear side edge of the protective lens 3, which is mainly used to shield the drive circuit of the electrically controlled reflective screen 2 and can achieve a mirror surface luster effect that the edge area completely matches the middle area. The obscuration layer 5 is a semi-reflective film, and the light sensor 4 is integrated in the rear side area of the obscuration layer 5 and is shielded by the obscuration layer 5. This can make the light from the rear light source directly pass through the semi-reflective film to the light sensor 4. When the light sensor 4 detects that the light intensity exceeds 2000 lux, the control circuit automatically increases the drive voltage of the electrically controlled reflective screen 2 to reduce the reflectivity to below 15% to achieve the anti-dazzling function. Thus, no hole is needed to be opened in the obscuration layer 5, which eliminates the visual fragmentation in the traditional structure. In addition, through the synergistic effect of mirror reflection and functional element hiding, the overall integrity and aesthetic quality of the product appearance are significantly improved.

[0032] In this embodiment, the protective lens 3 is a glass lens with a surface strengthening treatment. Thus, it has both internal structure protection and appearance optimization functions.

[0033] In the embodiment, the shielding layer 5 comprises a plurality of high-refractive-index medium films 51 and a plurality of low-refractive-index medium films 52, each layer of the high-refractive-index medium films 51 and each layer of the low-refractive-index medium films 52 are alternately arranged from front to back, the optical thickness of each of the high-refractive-index medium films 51 and the low-refractive-index medium films 52 is λ / 4, the material of the high-refractive-index medium films 51 is titanium dioxide (TiO2) with a refractive index of 2.4, and the material of the low-refractive-index medium films 52 is silicon dioxide (SiO2) with a refractive index of 1.46. The shielding layer 5 adopts a distributed Bragg reflector (DBR) structure formed by the high-refractive-index medium films and the low-refractive-index medium films with a λ / 4 optical thickness, which are alternately deposited by titanium dioxide (TiO2, n=2.4) and silicon dioxide (SiO2, n=1.46). The shielding layer 5 can be prepared by a magnetron sputtering process, the thickness tolerance of each film layer can be controlled within ±8%, the standard deviation of the transmittance in batch production is less than 1.5%, and the half-transmission / half-reflection of light is realized by the control of the optical thickness of the order of λ / 4 (the reflectivity is 45%±3% and the transmittance is 55%±3% in the visible light band), the characteristics of the half-reflection film are mainly determined by the number of film layers and the refractive index difference, and thus the overall reflectivity difference of the mirror surface of the electronic rearview mirror is less than 2%, and the mirror surface has a uniform silver-gray color effect in vision.

[0034] In the embodiment, the electrically-controlled reflective screen 2 adopts a liquid crystal light valve structure, which comprises a liquid crystal cell 21, a polaroid 22 and a reflective layer 23. The liquid crystal cell 21 comprises a first transparent plate 211, a second transparent plate 212 and a liquid crystal layer 213, the liquid crystal layer 213 is arranged between the first transparent plate 211 and the second transparent plate 212, is composed of nematic liquid crystal, the first transparent plate 211 is provided with a first transparent electrode and a first alignment layer (not shown in the figure) on the side close to the liquid crystal layer 213, and the second transparent plate 212 is provided with a second transparent electrode and a second alignment layer (not shown in the figure) on the side close to the liquid crystal layer 213; the polaroid 22 is attached to the front side of the liquid crystal cell 21, and the reflective layer 23 is arranged on the back side of the liquid crystal cell 21, and the reflective layer 23 adopts a reflective polaroid film (such as 3M RPM reflective polaroid film). In the reflective mode, the deflection angle of the liquid crystal molecules in the liquid crystal layer 213 of the liquid crystal cell 21 linearly changes with the driving voltage in the range of 0-5V, and the reflectivity is dynamically adjusted from 45% to 8%, so that the dynamic adjustment of the reflective brightness can be realized by adjusting the deflection angle of the liquid crystal molecules.

[0035] In the embodiment, the light sensor 4 adopts an infrared sensor. Thus, the interference of the visible light band on the light sensor can be effectively eliminated.

[0036] In the embodiment, the protective lens 3 and the shielding layer 5 are adhered to the front side of the electrically-controlled reflective screen 2 by the adhesive layer 6.

[0037] In the embodiment, the rear side of the electrically controlled reflective screen 2 is provided with a display screen 7 (such as a 6.5-inch TFT liquid crystal display screen). Thus, the electronic rearview mirror can be expanded into a streaming mirror, realizing the dual modes of reflection function and image display. The display area of the electronic rearview mirror is coincident with the central optical control area of the electrically controlled reflective screen 2, and in the streaming mode, the electrically controlled reflective screen 2 can be configured to be semi-transparent to ensure the transmission of the display screen picture.

[0038] In addition, it should be noted that the specific embodiments described in the specification can have different names and the like, and equivalent or simple changes made in accordance with the structure, features and principles of the utility model patent concept are included in the protection scope of the utility model patent. The skilled in the art of the utility model can make various modifications or supplements or use similar ways to replace the described specific embodiments, as long as they do not deviate from the structure of the utility model or exceed the scope defined in the claims, which shall belong to the protection scope of the utility model.

Claims

1. An electronic rearview mirror with light sensor, comprising an electrically controlled reflective screen, a protective lens and a light sensor, the protective lens being arranged in front of the electrically controlled reflective screen, a shielding layer being arranged on the rear side edge of the protective lens, the light sensor being integrated in the rear side area of the shielding layer; characterized in that: The shielding layer is a semi-reflective film, which is a multilayer optical film composed of multiple layers of high and low refractive index optical medium films.

2. An electronic rearview mirror with a light sensor according to claim 1, wherein: The shielding layer comprises multiple layers of high refractive index medium films and multiple layers of low refractive index medium films, each layer of high refractive index medium film and each layer of low refractive index medium film are arranged alternately from front to back.

3. An electronic rearview mirror with a light sensor according to claim 2, wherein: The high refractive index medium film is made of titanium dioxide, and the refractive index is 2.4; the low refractive index medium film is made of silicon dioxide, and the refractive index is 1.

46.

4. An electronic rearview mirror with a light sensor according to claim 3, wherein: The optical thickness of the high refractive index medium film and the low refractive index medium film is λ / 4.

5. An electronic rearview mirror with a light sensor according to claim 1, wherein: the light sensor is a photodiode. The protective lens and the shielding layer are adhered to the front side of the electrically controlled reflective screen through the adhesive layer.

6. An electronic rearview mirror with a light sensor according to claim 1, wherein: The electrically controlled reflective screen adopts a liquid crystal light valve structure, which comprises a liquid crystal cell, a polarizing plate and a reflective layer, the polarizing plate is attached to the front side of the liquid crystal cell, and the reflective layer is arranged on the back side of the liquid crystal cell.

7. An electronic rearview mirror with a light sensor according to claim 6, wherein: The liquid crystal cell comprises a first transparent plate, a second transparent plate and a liquid crystal layer, the liquid crystal layer is arranged between the first transparent plate and the second transparent plate, and is composed of nematic liquid crystal, the first transparent plate is provided with a first transparent electrode and a first alignment layer on the side close to the liquid crystal layer, and the second transparent plate is provided with a second transparent electrode and a second alignment layer on the side close to the liquid crystal layer.

8. An electronic rearview mirror with a light sensor according to claim 6, wherein: The reflective layer adopts a reflective polarizing film.

9. An electronic rearview mirror with a light sensor according to claim 1, wherein: The light sensor adopts an infrared sensor; or the light sensor is composed of a photodiode or a photoresistor.

10. An electronic rearview mirror with a light sensor according to claim 1, wherein: The back side of the electrically controlled reflective screen is provided with a display screen.

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