CN113810573A

CN113810573A - Lens module, camera and terminal

Info

Publication number: CN113810573A
Application number: CN202111056145.XA
Authority: CN
Inventors: 唐瑞锐
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2021-09-09
Filing date: 2021-09-09
Publication date: 2021-12-17

Abstract

The lens module of this application embodiment includes camera lens, light filter and image sensor. The lens comprises a plurality of lenses, and the surface shape of each lens is determined according to the radiation curve of sunlight in an infrared band; the optical filter can filter out light rays outside the infrared band; the image sensor is used for receiving light rays which sequentially pass through the lens and the optical filter to generate an image. The lens module, the camera and the terminal design the surface shape of the lens through the radiation curve of sunlight in an infrared band, so that the resolving power of the lens to infrared light is favorably improved, and the imaging quality of an image generated after an image sensor receives the infrared light is improved.

Description

Lens module, camera and terminal

Technical Field

The present application relates to the field of consumer electronics, and in particular, to a lens module, a camera, and a terminal.

Background

At present, a red light camera usually filters light except for light in an infrared band through an optical filter to receive the light in the infrared band, so as to perform infrared imaging.

Disclosure of Invention

The embodiment of the application provides a lens module, a camera and a terminal.

The lens module of this application embodiment includes camera lens, light filter and image sensor. The lens comprises a plurality of lenses, and the surface shape of each lens is determined according to the radiation curve of sunlight in an infrared band; the optical filter can filter out light rays outside the infrared band; the image sensor is used for receiving light rays which sequentially pass through the lens and the optical filter to generate an image.

The camera of one embodiment of the application comprises a shell and a lens module, wherein the lens module is arranged on the shell. The lens module comprises a lens, an optical filter and an image sensor. The lens comprises a plurality of lenses, and the surface shape of each lens is determined according to the radiation curve of sunlight in an infrared band; the optical filter can filter out light rays outside the infrared band; the image sensor is used for receiving light rays which sequentially pass through the lens and the optical filter to generate an image.

A terminal of another embodiment of the present application includes a housing and a camera. The camera is mounted on the housing. The camera comprises a lens module. The lens module comprises a lens, an optical filter and an image sensor. The lens comprises a plurality of lenses, and the surface shape of each lens is determined according to the radiation curve of sunlight in an infrared band; the optical filter can filter out light rays outside the infrared band; the image sensor is used for receiving light rays which sequentially pass through the lens and the optical filter to generate an image.

The lens module, the camera and the terminal design the surface shape of the lens through the radiation curve of sunlight in an infrared band, so that the resolving power of the lens to infrared light is favorably improved, and the imaging quality of an image generated after an image sensor receives the infrared light is improved.

Additional aspects and advantages of embodiments of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of embodiments of the present application.

Drawings

The above and/or additional aspects and advantages of embodiments of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic cross-sectional view of a lens module according to some embodiments of the present disclosure.

Fig. 2 is a schematic plan view of a terminal according to some embodiments of the present application.

Fig. 3 is a graph of radiation curves for certain embodiments of the present application.

FIG. 4 is a graph of the response of an image sensor according to certain embodiments of the present application.

FIG. 5 is a schematic view of a lens configuration according to certain embodiments of the present application.

Fig. 6 is a schematic structural diagram of an optical filter according to some embodiments of the present disclosure.

Detailed Description

The following further describes embodiments of the present invention with reference to the drawings. The same or similar reference numbers in the drawings identify the same or similar elements or elements having the same or similar functionality throughout.

In addition, the embodiments of the present invention described below with reference to the accompanying drawings are exemplary only for the purpose of explaining the embodiments of the present invention, and are not to be construed as limiting the present invention.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

The near-infrared camera module is an imaging camera with the working wavelength of 780nm to 2500nm, and because objects can radiate infrared energy outwards, the near-infrared camera can image the objects without depending on the reflection of sunlight. Therefore, near-infrared cameras are currently commonly used in the fields of night vision, security and monitoring. Generally, in order to improve the response of the camera module in near infrared light, the sensor size and pixel of the security monitoring camera are large, the resolution ratio is low, and the camera module cannot be directly used in a mobile terminal.

The lens in the conventional mobile terminal is generally designed for visible light, so that the resolving power of the lens for the light in the infrared band is low, and the response degree of the image sensor for the infrared band is also low, so that the noise of infrared imaging is strong, and the imaging quality is poor.

Referring to fig. 1, a lens module 10 according to an embodiment of the present disclosure includes a lens 11, a filter 12, and an image sensor 13. The lens 11 comprises a plurality of lenses 111, and the surface shape of the lenses 111 is determined according to the radiation curve of sunlight in an infrared band; the optical filter 12 can filter light except for infrared bands; the image sensor 13 is used for receiving light rays sequentially passing through the lens 11 and the filter 12 to generate an image.

The lens module 10 of this application designs the shape of face of camera lens 11 through the radiation curve of sunlight at infrared band, is favorable to promoting the analytic power of camera lens 11 to the infrared light to reduce the noise of infrared imaging, improve the imaging quality of the image that image sensor 13 generated after receiving the infrared light.

Referring to fig. 1 and 2, a terminal 1000 according to an embodiment of the present disclosure includes a housing 200 and a camera 100. The camera 100 is mounted on the cabinet 200.

Terminal 1000 can be a smart watch, cell phone, tablet, display device, laptop, teller machine, gate, head-up display device, game console, and the like. As shown in fig. 2, in the embodiment of the present application, terminal 1000 is a mobile phone as an example for explanation, and it is understood that the specific form of terminal 1000 is not limited to the mobile phone. The housing 200 can also be used to mount functional modules of the terminal 1000, such as a display device, an imaging device, a power supply device, and a communication device, so that the housing 200 provides protection for the functional modules, such as dust prevention, drop prevention, and water prevention.

The camera 100 includes a housing 20 and a lens module 10. The lens module 10 is disposed on the housing 20, and the housing 20 may be a part of the cabinet 200, or the housing 20 is mounted on the cabinet 200 such that the camera 100 is mounted on the cabinet 200. The camera 100 may be a front camera 100, a rear camera 100, or an off-screen camera 100, etc.

The lens module 10 includes a lens 11, a filter 12, an image sensor 13, and a barrel 14, and the lens 11, the filter 12, and the image sensor 13 are disposed in the barrel 14.

The lens 11 includes a plurality of lenses 111, and when designing the surface shape of each lens 111 of the lens 11, the radiation curve of the scene in the infrared band under sunlight can be obtained according to the actual application scene, so as to determine the weight of each wavelength in the infrared band according to the radiation curve of the infrared band.

For example, referring to fig. 3, curves a and B are the radiation curve of sunlight at the upper air boundary and the radiation curve of sunlight reaching the ground, respectively. When the camera 100 needs to shoot a mountain in a far distance, it may be determined that an actual application scene is a telephoto scene, and at this time, it may be determined that a radiation curve for designing the lens 11 is a curve a, so that an resolving power of the lens 11 to light passing through an infrared band of the atmosphere may be improved, thereby improving an imaging quality.

Or, when the camera 100 needs to shoot a normal ground scene, it may be determined that the actual application scene is a close-up scene, and at this time, it may be determined that the radiation curve for designing the lens 11 is the curve B, so that the resolving power of the lens 11 on the light of the infrared band reaching the ground is improved, and the imaging quality is improved.

For example, the infrared band may be 700 nanometers (nm) to 1100nm, and 700nm, 800nm, 900nm, 1000nm and 1100nm are the index wavelengths in the infrared band, and the weight of each index wavelength may be determined according to the numerical value of the index wavelength on the longitudinal axis of the radiation curve, as shown in fig. 3, taking curve a as an example, the weight ratio of the numerical values corresponding to 700nm, 800nm, 900nm, 1000nm and 1100nm is 30:25:20:15:10, respectively, that is, the weight of the wavelength of 700nm is 0.3, the weight of the wavelength of 800nm is 0.25, the weight of the wavelength of 900nm is 0.2, the weight of the wavelength of 1000nm is 0.15, and the weight of the wavelength of 1100nm is 0.1. In this manner, the weight of each marker wavelength can be determined so that the surface shape of each lens 111 of the lens 11 designed for the weight of the wavelength has a stronger resolving power for light in the infrared band of 700nm to 1100 nm. The lens 11 of the present embodiment has a modulation transfer function value of greater than 71.9% for light having a wavelength between 700nm and 1100nm for 110 lines per mm, wherein the modulation transfer function value for 110 lines per mm is also greater than 64% for the out-field.

The angle of view of the lens 11 is in the interval [85 degrees, 89 degrees ], and is large. The focal length of the lens 11 is in the interval [1.94 millimeters (mm), 2.06mm ], and the focal length of the lens 11 is smaller, which is beneficial to reducing the optical total length of the lens 11, so that the optical total length of the lens 11 is in the interval [3.03mm, 3.17mm ]. And the distortion of the lens 11 of the application is less than 2%, and the imaging effect is good.

The image sensor 13 can receive light rays in an infrared band passing through the lens 11 for imaging, but the image sensor 13 has different response degrees to different wavelengths, so the weight of the wavelength can be adjusted according to the response curve of the image sensor 13 to the response degrees of the different wavelengths.

Referring to fig. 4, a response curve C of the image sensor 13 to the light in the infrared band is shown, and a first compensation coefficient of each wavelength is determined according to a corresponding value (which may represent a degree of response to the light, and is maximum 1) of each wavelength in the infrared band on a vertical axis of the response curve C, where the first compensation coefficient is a coefficient value of a weight of the wavelength, and the adjusted wavelength weight is a product of the wavelength weight before adjustment and the first compensation coefficient.

For example, if the value is smaller than the first threshold (e.g., the first threshold is 0.1), it indicates that the image sensor 13 has a low response degree to the light with the wavelength corresponding to the value, as shown in fig. 4, the value corresponding to 1000nm is already close to 0, and at this time, the wavelength corresponding to the value smaller than the first threshold may not be compensated, or the wavelength corresponding to the value smaller than the first threshold may be negatively compensated (i.e., the first compensation coefficient is smaller than or equal to 1), and if the value is larger, the first compensation coefficient is larger, i.e., the first compensation coefficient of the weight of the wavelength has a positive correlation with the value. If the first compensation coefficient for the weight of the wavelength of 1000nm is 1 and the first compensation coefficient for the weight of the wavelength of 1100nm is 0.5, the weight ratio of the index wavelength is adjusted to 30:25:20:15: 5.

the weight of the wavelength can be adjusted according to a second compensation coefficient determined by the wavelength, the second compensation coefficient can be larger than, smaller than or equal to the first compensation coefficient, the second compensation coefficient is a coefficient value of the weight of the wavelength, and the weight of the wavelength after adjustment is a product of the weight of the wavelength before adjustment and the second compensation coefficient. For example, in a telephoto scene, it is necessary to improve the receiving capability of light rays with wavelengths having stronger transmittance (i.e., the wavelengths are larger), and therefore, the larger the wavelength is, the larger the second compensation coefficient corresponding to the weight of the wavelength is, that is, the second compensation coefficient and the wavelength have a positive correlation. If the second compensation coefficient for the weight of the wavelength of 700nm is 5/6, the second compensation coefficient for the weight of the wavelength of 800nm is 6/5, and the second compensation coefficient for the weight of the wavelength of 800nm is 5/4, the weight ratio of the index wavelength is adjusted to 25: 30:25: 15: 5.

of course, a second threshold may also be set, and for a wavelength corresponding to a numerical value smaller than the second threshold, if the second threshold is larger than the first threshold, if the second threshold is 0.2, the response degree corresponding to the wavelength is too low, and at this time, the influence degree of the wavelength on the wavelength weight is small, and even if a higher weight is given, the receiving capability of the image sensor 13 for the light with stronger penetration is still low. When the value is greater than the second threshold (for example, the second threshold is 0.2), it indicates that the response degree of the image sensor 13 to the light with the wavelength corresponding to the value is higher, and at this time, the influence degree of the wavelength on the weight of the wavelength is larger, and the second compensation coefficient may have a positive correlation with the wavelength, so as to improve the receiving capability of the image sensor 13 to the light with stronger penetration. Further, the weight of the wavelength corresponding to the value between the first threshold value and the second threshold value may not be adjusted. In other embodiments, the second threshold may be equal to the first threshold, so that the weight of the wavelength weight of the entire infrared band is adjusted.

Thus, the response curve C of the image sensor 13 assists in adjusting the weight of the wavelength, so that the receiving capability of the image sensor 13 for the light in the infrared band can be improved, and the infrared imaging quality can be improved.

Referring to fig. 5, the lens 111 includes a lens body 1111 and an antireflection film 1112, and the antireflection film 1112 is disposed on the lens body 1111. The antireflection film 1112 is used to enhance the transmittance of the infrared band light on the lens 111.

The lens body 1111 and the antireflection film 1112 have good transmittance for light of all wavelengths, for example, the lens body 1111 is a glass lens 111, and the surface shape of the lens 111 is designed by the adjusted wavelength weight, so that the resolving power for light of an infrared band is stronger. The antireflection film 1112 further enhances the transmittance of the infrared light in the lens 111.

Referring to fig. 6, the filter 12 includes a filter body 121 and a filter film 122, the filter film 122 is disposed on the filter body 121, and the filter film 122 can filter light outside the infrared band, so that the light in the infrared band passing through the lens 11 passes through the filter body 121 and then enters the image sensor 13 for imaging.

The optical filter 12 may be a white glass optical filter, and the white glass has good transmittance to light rays in all wavelength bands (the transmittance of the white glass optical filter to visible light wavelength bands and infrared wavelength bands (i.e., 350nm to 1100nm) exceeds 92%), and it can be understood that, in order to prevent light rays except for the infrared wavelength bands from entering the image sensor 13 and affecting the infrared imaging effect, the optical filter film 122 needs to be disposed to filter light rays except for the infrared wavelength bands. For example, the filter 122 may be a reflective filter or an absorptive filter, and in one embodiment, taking the reflective filter as an example, the average transmittance thereof exceeds 92% at 700 and 1100nm, and the average transmittance thereof is less than 3% at 400 and 700nm, so as to greatly intercept visible light and reduce the coverage of infrared information.

Certainly, the image sensor 13 in this embodiment has a response degree of substantially 0 for light with a wavelength exceeding 1100nm, so that, when filtering, only light in a visible light band (for example, 400nm to 700nm) needs to be filtered, and the same effect of filtering light outside the infrared band can be achieved (the transmittance of the coated white glass filter in the visible light band and the infrared band is less than 3% at 400nm to 700nm, and exceeds 92% at 700 and 1100nm), and the requirement for filtering the filter film 122 is low, which is beneficial to reducing the cost of the filter film 122.

The thickness of the optical filter 111 is within the interval [0.27 mm, 0.33 mm ], and is thinner, which is beneficial to reducing the volume of the lens module 10.

Referring to fig. 1 again, the lens barrel 14 includes an accommodating space 141, and the lens 11 and the filter 12 are disposed in the lens barrel 14 and located in the accommodating space 141. The lens module 10 further includes a circuit board 15, the lens barrel 14 is disposed on the circuit board 15, the image sensor 13 is disposed on the circuit board 15 and electrically connected to the circuit board 15, and the image sensor 13 is located in the accommodating space 141.

The lens module 10, the camera 100 and the terminal 1000 of the embodiment of the present application design the surface shape of the lens 11 through the radiation curve of sunlight in the infrared band, and adjust the weight of the wavelength through the response curve of the image sensor 13, thereby adjust the surface shape of the lens 11, make the resolving power of the lens 11 to the light of the infrared band, and the light filter 12 has higher transmittance to the whole band and can filter the light except the infrared band, thereby improving the transmittance of the light filter 12 to the infrared band, thereby improving the imaging quality of the image generated after the image sensor 13 receives the infrared light.

In the description of the specification, reference to the terms "certain embodiments," "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, unless specifically limited otherwise.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and those skilled in the art can make changes, modifications, substitutions and alterations to the above embodiments within the scope of the present invention, which is defined by the claims and their equivalents.

Claims

1. A lens module, comprising:

the lens comprises a plurality of lenses, and the surface shape of each lens is determined according to the radiation curve of sunlight in an infrared band;

the optical filter can filter light except for the infrared band;

the image sensor is used for receiving light rays which sequentially pass through the lens and the optical filter to generate an image.

2. The lens module as claimed in claim 1, wherein the surface shape of the lens is determined according to the weights of different wavelengths of the infrared band when the lens is designed, the weight of the wavelength is determined according to the radiance curve, and the weight of the wavelength is adjusted according to the response curve of the image sensor to the infrared band.

3. The lens module as claimed in claim 2, wherein the first compensation factor of the weight of the wavelength has a positive correlation with the value corresponding to the response curve when the value is smaller than a first threshold.

4. The lens module as claimed in claim 3, wherein the weight of the wavelength is further adjustable according to a second compensation factor determined by the wavelength.

5. The lens module as claimed in claim 4, wherein when the wavelength is greater than a second threshold value in the response curve, the second compensation factor is in positive correlation with the wavelength, and the second threshold value is greater than the first threshold value.

6. The lens module as claimed in claim 1, wherein the lens includes a lens body and an anti-reflection film disposed on the lens body for enhancing transmittance of the infrared light on the lens.

7. The lens module as claimed in claim 1, wherein the filter comprises a filter body and a filter disposed on the filter body, the filter being capable of filtering light except the infrared band, so that the light in the infrared band passes through the filter body and enters the image sensor.

8. The lens module as claimed in claim 7, wherein the filter is a reflective filter or an absorptive filter.

9. The lens module as claimed in claim 1, wherein the thickness of the filter is in the interval [0.27 mm, 0.33 mm ].

10. The lens module as claimed in claim 1, wherein the angle of view of the lens is in the interval [85 degrees, 89 degrees ].

11. The lens module as claimed in claim 1, wherein the focal length of the lens is in the interval [1.94 mm, 2.06mm ].

12. The lens module as claimed in claim 1, wherein the total length of the lens is in the interval [3.03mm, 3.17mm ].

13. The lens module as claimed in claim 1, wherein the distortion of the lens is less than 2%.

14. A camera comprising a housing and the lens module as claimed in any one of claims 1 to 9, wherein the lens module is disposed in the housing.

15. A terminal comprising a housing and the camera of claim 14, the camera disposed in the housing.