WO2016112856A1

WO2016112856A1 - Optical filter, camera module and manufacturing method thereof

Info

Publication number: WO2016112856A1
Application number: PCT/CN2016/070862
Authority: WO
Inventors: 郭楠; 熊科强; 王明珠; 张哲宁; 赵波杰; 方银丽
Original assignee: 宁波舜宇光电信息有限公司
Priority date: 2015-01-15
Filing date: 2016-01-14
Publication date: 2016-07-21

Abstract

Provided are an optical filter (22) capable of preventing a camera module from producing stray light, camera module using the optical filter (22), and manufacturing method thereof. The camera module comprises a camera lens (20), a support (21) holding the camera lens (20), the optical filter (22) provided below the camera lens (20), and an image sensor (23) provided below the optical filter (22). The optical filter (22) comprises an infrared cut-off optical filter (221) and a light blocking film (222) provided on a surface of the infrared cut-off optical filter (221). The light blocking film (222) is provided with a window (2221) at a center thereof, such that a light transmitting region is formed at the center of the infrared cut-off optical filter (221), and a light blocking region is formed outside the light transmitting region.

Description

Filter and camera module and manufacturing method thereof

Technical field

The present invention relates to the field of camera modules, and more particularly to a filter for effectively intercepting light incident on a surface of a gold wire around an image sensor and light of an inner wall of a lens holder, and a camera module using the same.

Background technique

As mobile phone camera modules develop toward high-pixel, large-aperture, and ultra-thin, consumers are increasingly demanding image quality for camera modules. As shown in FIG. 1 , the existing mobile phone camera module includes a lens 10 , a bracket 11 for fixing the lens 10 , a filter 12 disposed under the lens 10 , and an image sensor 13 disposed under the filter 12 . And a circuit board 14 electrically coupled to the image sensor 13. The filter 12 is mainly an infrared cut filter, and its function is to filter the infrared light in the light, so that the imaging effect of the camera module is close to the imaging effect of the human eye.

However, the existing camera module often has stray light problems when shooting. Figure 2 shows that when the light source moves out of the imaging surface 35 ° ~ 40 °, the edge of the corresponding position of the imaging surface presents a purple-red stray light, which affects the imaging quality of the mobile phone camera module. According to research and analysis, the main cause of this problem is that large-angle light is incident on the surface of the gold wire connected to the image sensor 13 and the wiring board 14 or the stray light generated by the reflection on the inner wall of the bracket 11. As shown in FIG. 1, the light is reflected by the raised area 111 of the open window edge of the bracket 11, or is reflected by the surface area 141 of the plurality of gold lines connected to the circuit board 14 and the image sensor 13, and then enters the inside of the camera module. It is imaged by the image sensor 13 to cause stray light.

Summary of the invention

The main purpose of the present invention is to provide a camera module that can effectively intercept the light incident on the surface of the gold wire around the image sensor and the light of the inner wall of the lens holder to prevent the interference light from being reflected to the image sensor. The effective area thus forms stray light during imaging.

Another object of the present invention is to provide a camera module that blocks possible interference light through a filter, thereby preventing this portion of light from being incident on other components in the camera module, and being repeatedly Reflected to the effective area of the image sensor, affecting the quality of the image.

Another object of the present invention is to provide a filter that can block interference light that may cause stray light when mounted on a camera module, and avoids that other portions of the light are incident on the camera module. On the component, the effective area that is reflected multiple times to the image sensor forms stray light.

Another object of the present invention is to provide a filter provided with a light-blocking film, and the filter does not need to change the structure of the original filter at the time of fabrication, and has a simple manufacturing process and low cost.

To achieve the above objective, the present invention provides a camera module including a lens, a bracket for fixing the lens, a filter disposed under the lens, and a filter disposed under the filter. An image sensor, wherein the filter comprises an infrared cut filter and a light blocking film, the light blocking film is disposed on the surface of the infrared cut filter, and the light blocking film has a window opening therebetween. A light transmissive region is formed in the middle of the infrared cut filter, and a light blocking region is formed outside the light transmissive region.

Preferably, the light blocking film is annular, the inner frame of the light blocking film forms the window, and the light blocking film is disposed on the edge of the infrared cut filter on the infrared cut filter. Upper surface.

Preferably, the inner frame size of the light blocking film is calculated by calculating an analog image height of each of the main ray, the upper ray and the lower ray according to each parameter of the camera module, in each field of view. The maximum simulated image height is used as the inner frame size of the light blocking film.

Preferably, the bracket extends inwardly from a mounting platform, a window is formed in the middle of the mounting base, the filter is mounted on the mounting platform, and a vertical projection of the outer frame of the light blocking film is at the mounting platform Within the scope.

Preferably, the light blocking film is applied to the infrared cut filter by a yellow light process or a silk screen process, and the shape of the mask used is the same as that of the light blocking film by the yellow light process. When the screen printing process is utilized, the shape of the ink-permeable region of the screen printing plate used is the same as that of the light-blocking film.

Preferably, the light-blocking film has a thickness of 2 μm to 12 μm.

Preferably, the camera module further includes a circuit board, and the circuit board and the image sensor are electrically connected by a plurality of gold wires.

Preferably, the light-blocking film is a black absorbing material capable of absorbing more than 95% of light energy, less than 0.2% of light energy is transmitted, and less than 3.5% of light energy is reflected.

Preferably, the light blocking film is a black ink coating, which is a light absorbing material, and light incident on the light blocking film is absorbed by the light blocking film, so that the light is not reflected to the imaging mode. The surface of other components in the group or through the filter, in one embodiment, the light absorbing material may be a carbon-containing resin, that is, it can absorb light and facilitate the blocking Light film coating formed on the filter Sheet surface.

The present invention further provides a filter, the filter is adapted to be mounted on a camera module, the camera module includes a lens disposed above the filter, and a bracket for fixing the lens. And an image sensor disposed under the filter, the filter includes an infrared cut filter and a light blocking film, the light blocking film is disposed on the surface of the infrared cut filter, The light blocking film has a window in the middle to form a light transmissive area in the middle of the infrared cut filter, and a light blocking area is formed outside the light transmissive area.

The invention also provides a method for manufacturing a filter of a camera module, the method comprising the steps of: (a) providing an annular light blocking film on an infrared cut filter of a camera module, in the infrared A light transmissive region is formed in the middle of the cut filter, and a light blocking region is formed outside the light transmissive region.

Preferably, the light blocking film is disposed on a surface of the infrared cut filter opposite to a lens of the camera module.

Preferably, before step (a), step (b) and/or (c) is further included, wherein step (b) is: determining an inner frame size of the light-blocking film, so as to pass the inner frame of the light-blocking film Directly entering an image sensor of the camera module; step (c) is: determining a size of the outer frame of the light blocking film, so that a vertical projection of the outer frame of the light blocking film is mounted on the filter Within the scope of a mounting platform.

Preferably, determining the inner frame size of the light-blocking film in step (b) comprises the following steps:

(b1) simulating an angle between the chief ray, the upper ray, and the lower ray of each field according to the optical path condition of the internal optical system of the lens;

(b2) obtaining a radius of curvature of a last lens of the lens, a distance of the lens to the filter, a distance of the filter to the image sensor, and a refractive index and thickness of the filter ;

(b3) Calculating the simulated image heights of the chief ray, the upper ray, and the lower ray of each field of view according to the above parameters, and using the maximum simulated image height in each field of view as the inner frame size of the light blocking film.

Preferably, after the step (b3), a step of correcting the size of the window 2221 is further included: (b4) increasing the size of the window 2221 obtained in the step (b3) according to the assembly offset during the process The size of the fenestration 2221 is corrected by the corresponding offset.

Preferably, in step (a), the light blocking film is applied to the surface of the infrared cut filter by a yellow light process, specifically comprising the steps of: cleaning and drying the infrared cut filter; Coating a primer on the infrared cut filter; spin-coating the photoresist on the infrared cut filter; softly drying the infrared cut filter; and performing alignment exposure on the infrared cut filter; The cut-off filter is post-baked; the infrared cut filter is developed; the infrared cut filter is hard-baked; The cut filter is etched to form the filter. The photoresist is a black absorbing material that absorbs more than 95% of the light energy, less than 0.2% of the light energy is transmitted, and less than 3.5% of the light energy is reflected.

Preferably, in step (a), the light blocking film is applied to the surface of the infrared cut filter by a silk screen process, and specifically includes the following steps: applying ink to the infrared cutoff by a screen printing plate a filter; baking the aforementioned infrared cut filter to obtain the filter. The ink is a black absorbing material capable of absorbing more than 95% of light energy, less than 0.2% of light energy is transmitted, and less than 3.5% of light energy is reflected.

DRAWINGS

1 is a cross-sectional view of a conventional camera module.

FIG. 2 is a schematic diagram of a simulation of a conventional camera module that generates interference light when a large angle of light is incident.

3 is a cross-sectional view of a preferred embodiment of a camera module in accordance with the present invention.

4 is a schematic illustration of a preferred embodiment of a filter in accordance with the present invention.

Fig. 5 is a view showing an optical path simulation when calculating the size of the light-blocking film of the present invention.

FIG. 6 is a comparison diagram of the camera module of the present invention and a conventional camera module in actual operation.

Detailed ways

The following description is presented to disclose the invention to enable those skilled in the art to practice the invention. The preferred embodiments in the following description are by way of example only, and other obvious variations will occur to those skilled in the art. The basic principles of the invention as defined in the following description may be applied to other embodiments, modifications, improvements, equivalents, and other embodiments without departing from the spirit and scope of the invention.

Figure 3 shows a camera module of the present invention. The camera module includes a lens 20, a bracket 21 for fixing the lens 20, a filter 22 disposed under the lens 20, an image sensor 23 disposed under the filter 22, and A circuit board 24 electrically coupled to the image sensor 23. A plurality of gold wires 25 are disposed on the circuit board 24.

As shown in FIG. 3 and FIG. 4 , the filter 22 includes an infrared cut filter 221 and a light blocking film 222 , and the light blocking film 222 is disposed above or below the infrared cut filter 221 . The light blocking film 222 has a window 2221 in the middle thereof to form a light transmitting region in the middle of the infrared cut filter 221, and a light blocking region is formed outside the light transmitting region. The light-transmitting region is a region opposite to the window 2221, and the light-blocking region is a region opposite to the light-blocking film 222, when light is incident on the light-transmitting region In the field, the light filter 22 can pass through the light blocking film 222 when light is incident on the light blocking region, and cannot pass through the filter 22.

The infrared cut filter 221 is mainly used for intercepting infrared light in the incident light to prevent infrared light in the light from being incident on the image sensor 23, thereby affecting the color quality of the image.

The light blocking film 222 is annular, and the inner frame of the light blocking film 222 forms the opening window 2221. Since the light blocking film 222 is annular, the light blocking film is disposed on the infrared cut filter. An edge of the light sheet 221 forms the light blocking region at an edge of the infrared cut filter 221, and the light transmitting region is formed in the middle of the infrared cut filter 221 . The light blocking film 222 is prepared using an opaque material, so that the light blocking film 222 makes the edge of the filter 22 opaque, and the light incident on the edge of the filter 22 is prevented from transmitting through the Filter 22. The purpose of providing the light-blocking film 222 at the edge of the infrared cut filter 221 is that the interference light that causes the stray light phenomenon is mostly a large angle of incident light, and the interference light is mainly after passing through the lens 20. Incident to the edge position of the filter 22, if the interference light can pass through the filter 22, the interference light may be incident on the inner wall of the bracket 21 or the surface of the gold wire 25, It is then reflected into the image sensor 23 to produce stray light during imaging. Therefore, the light blocking film 222 is disposed at the edge of the filter 22 to prevent the interference light from passing through the filter 22.

The light blocking film 222 may be disposed above or below the infrared cut filter 221 to prevent the interference light incident on the edge of the filter 22 from passing through the filter 22 can. Preferably, the light blocking film 222 is disposed above the infrared cut filter 221, that is, on the side of the infrared cut filter 221 opposite to the lens 20, to enter the incident light. The infrared cut filter 221 is previously blocked by the interference light.

The filter 22 may be disposed under the lens 20 through the bracket 21 or may be disposed under the lens 20 by other components. Preferably, the filter 22 is supported by the bracket 21 under the lens 20.

Preferably, the bracket 21 extends inwardly from a mounting base 211. The filter 22 is fixed between the lens 20 and the image sensor 23 by the mounting base 211, and the mounting table 211 is formed in the middle. a window, the opening window 2221 of the filter 22 is located in a region of the window, and the filter 22 is connectable to the mounting table 211 through an edge of the upper surface such that the mounting table 211 is at The upper surface of the filter 22 may also be connected to the mounting table 211 through an edge of the lower surface such that the mounting table 211 is below the filter 22. The filter 22 is fixed to the device by glue bonding In the mounting table 211, a portion where the filter 22 is connected to the mounting table 211 is a dicing area. In determining the size of the outer frame of the light-blocking film 222, it is necessary to consider the size of the squeegee area, that is, the size of the mounting table, and the details are described in the following sections.

In addition, the filter 22 may not be fixed in the bracket 21 through the mounting base 211, and the filter 22 is directly glued to the inner wall of the bracket 21 through its side edge. The size of the outer frame of the light blocking film 222 does not need to be considered in the dicing area, and the outer frame size of the light blocking film 222 is the same as the size of the infrared cut filter 221 .

The light blocking film 222 may be a self-supporting material that is opaque to light, and may be supported by the bracket 21 to be disposed on an upper surface or a lower surface of the filter 22 . The light blocking film 222 may also cover the infrared cut filter 221 and fix the light blocking film 222 to the surface of the infrared cut filter 221 by an adhesive.

The light blocking film 222 may also be an opaque coating, and the light blocking film 222 is applied to the upper surface or the lower surface of the infrared cut filter 22 . When the light-blocking film 222 is made of an opaque paint, the structure of the camera module and the filter 22 can be simplified, and a better light blocking function can be achieved. Preferably, the light-blocking film 222 is made of an opaque paint, and the light-blocking film 222 is applied to the infrared-cut filter 221, and various coating methods can be used. An embodiment in which the film 222 is applied to the infrared cut filter 221 is shown.

Example 1.

The light-blocking film 222 is applied to the surface of the infrared cut filter 221 by photolithography, and the photolithography method is a conventional yellow light process.

The photoresist used in the yellow light process is a photosensitive material. The photoresist has unique characteristics. Under the action of UV light, it undergoes chemical changes and becomes a substance that is easily soluble in acid or alkali. Applying a photoresist to the substrate, providing a corresponding mask according to the shape required by the product, masking the mask on the photoresist, and then exposing the photoresist so that the photoresist is not covered by the mask A chemical change occurs in the region, and then the portion of the photoresist is dissolved or retained with an acid or a base to form a pattern that is identical or complementary to the shape of the mask.

The photoresist used in the present invention is an opaque coating which has opaque characteristics in addition to the photosensitive characteristics of conventional photoresists.

The photomask of the present invention may have an annular mask of the same shape as the light shielding film 222, or a mask having the same shape as the opening window 2221 of the light shielding film 222, but only needs to be dissolved after exposure. The solvents used are different depending on the area. Preferably, the photomask adopts the light shielding film 222 An annular mask of the same shape is applied to the infrared cut filter 221 during fabrication, and the photomask is exposed on the photoresist for exposure, which needs to occur in the middle after exposure The chemically-changed photoresist is removed, and the light-shielding film 222 is formed in a region covered by the photomask. The outer frame size of the photomask is the outer frame size of the light-shielding film 222. The inner frame size is the inner frame size of the light shielding film 222.

The specific yellow light process may include the following steps: 1. Surface treatment, including cleaning and drying the infrared cut filter 221; 2. Coating the bottom; 3. Spin coating the photoresist, this step will be the photoresist Uniformly applied to the surface of the infrared cut filter; 4. soft bake; 5. alignment exposure; 6. post-bake; 7. development; 8. hard bake; 9. etching.

The precision of coating the light-blocking film 222 by the yellow light process can reach 25 μm, and when the microscope is enlarged to 85 times, the edge of the light-blocking film 222 is smooth, and the corner straight angle is better. When the yellow light process is used, the thickness of the light-blocking film 222 can be 2 μm to 3 μm.

Example 2.

The light blocking film 222 is coated on the infrared cut filter 221 by a silk screen process. The ink used in the silk screen printing is an opaque material, and the ink is applied to the light blocking region of the infrared cut filter 221 by a silk screen process, thereby forming the light blocking film 222. The silk screen printing process can be carried out by the ink passing through the mesh of the black-plated position of the screen printing plate, and the basic principle of the mesh of the light-transmitting area being impermeable to the ink.

The shape of the ink permeable portion of the screen printing plate should be consistent with the shape of the light blocking film 222, and is an annular shape. The other portions of the screen printing plate are impermeable to ink. At the time of fabrication, the screen printing plate is first aligned with the infrared cut filter 221, the ink is poured onto the screen printing plate, and a certain amount of the ink is applied by the squeegee blade. The ink is pressed onto the infrared cut filter 221 through the mesh of the screen printing plate to apply the ink to the surface of the infrared cut filter 221 . Subsequent steps include baking and the like.

The precision of coating the light-blocking film 222 by the silk screen process can reach 35 μm, and when the microscope is enlarged to 85 times, the edge of the light-blocking film 222 is rough, and the right-angled corners are arc-shaped, but the overall pair The performance of the camera module has little effect. When the silk screen process is employed, the thickness of the light-blocking film 222 can be 7 μm to 12 μm.

Compared with the yellow light process, the silk screen printing process has a simple manufacturing process and a low cost, and although the precision is poor, it is sufficient to meet the accuracy requirements of a general camera module. Therefore, an appropriate process can be selected according to the accuracy requirements of the camera module. Optional for high-precision module manufacturing and ultra-thin solution modules The yellow light process technology, the general module process requirements can use the silk screen process.

The above two embodiments relate to the size and shape of the light-blocking film 222 when the opaque material is applied to the infrared cut filter 221 . The size of the light-blocking film 222 is determined, that is, the inner frame size and the outer frame size of the light-blocking film 222 are determined.

When the filter 22 is mounted on the mounting table 211, the vertical projection of the outer frame of the light-blocking film 222 should be located on the mounting table, that is, the edge of the mounting table 211 is in the block. Within the projection range of the light film 222, there is no gap between the edge of the mounting table 211 and the vertical projection of the light blocking film 222, thereby preventing light from transmitting to the outer frame of the light blocking film 222 and the mounting. The interval between the stages 211 is incident on the inner wall of the holder 21.

The inner frame size of the light blocking film 222 is the size of the opening window 2221. If the opening window 2221 is too small, a vignetting angle of the imaging area may be generated. If the opening window 2221 is too large, part of the interfering light may be missed, thereby causing stray light. The optimal size of the fenestration 2221 can be derived from optical path experiments or simulation analysis. A method of calculating the size of the window 2221 is provided below:

a) simulating an angle between the chief ray, the upper ray, and the lower ray of each field according to the optical path condition of the optical system inside the lens 20;

b) obtaining the radius of curvature of the last lens of the lens 20, the distance of the lens 20 to the filter 22, the distance of the filter 22 to the image sensor 23, the filter 22 refractive index and thickness;

c) calculating the simulated image heights of the chief ray, the upper ray and the lower ray of each field of view according to the above parameters, and taking the maximum simulated image height of the chief ray, the upper ray and the lower ray in each field of view as the size of the fenestration 2221.

A simulation diagram for calculating the size of the opening window 2221 in the width direction is shown in FIG. Firstly, the angles of the chief ray, the upper ray and the lower ray of the lens 20 in the field of view are simulated. The angle between the chief ray, the upper ray and the lower ray in one field of view is (θ ₁ , θ ₂ , θ ₃ ), the angle between the chief ray, the upper ray and the lower ray in the other field of view is (θ ₄ , θ ₅ , θ ₆ ); then the radius of curvature (r) of the last side of the lens 20 is obtained by simulation; the parameters of the camera module, the lens 20 to obtain a distance (L ₁₎ 22 of the filter, the filter is the distance (L ₂₎ of the image sensor 23, the filter The refractive index (n) of the sheet 22 and the thickness (t) of the filter 22; calculating the simulated image heights of the chief ray, the upper ray and the lower ray in each field of view according to the above parameters, in one field of view The simulated image heights are (H ₁ , H ₂ , H ₃ ), and the simulated image heights in the other field of view are (H ₄ , H ₅ , H ₆ ), respectively, and H ₁ , H ₂ , H ₃ , H _{4 are} compared. The size of H ₅ and H ₆ and the maximum simulated image height H _{max are} the dimensions of the window 2221 in the direction of the field of view. The dimensions of the high-direction and diagonal directions of the fenestration 2221 are calculated in the same manner, thereby obtaining the size of the fenestration 2221, which is a size that does not affect the real-time imaging of the camera module.

When the size of the opening window 2221 is the minimum size obtained by the above simulation, the interference light is blocked outside the opening window 2221, that is, may be incident on the inner wall of the bracket 21 and the surface of the gold wire 25. The interference light is blocked by the light blocking film 222 and cannot pass through the filter 22, thereby avoiding stray light.

The above simulation process assumes that the center of the filter 22 is on the same optical axis as the center of the lens 20 and the image sensor 23, that is, the center of the opening window 2221 of the light shielding film 222 and the The lens 20 and the center of the image sensor 23 are on the same optical axis. However, it is considered that there may be an assembly offset in the actual manufacturing process, for example, the filter 22 and the bracket 21 are attached with an offset, the bracket 21 and the wiring board 24 are attached with an offset, the lens The attachment offset of the 20 or the like, if the light shielding film 222 is also set according to the size of the above-mentioned simulation calculation, it may cause a part of the disturbance light to be missed or cause an image vignetting, and therefore, the size and position of the light shielding film 222 are determined. In this case, the offset should be taken into account, and the offset is added to the dimension design to obtain the optimum size of the window 2221.

By calculating the optimal size of the window 2221, light incident through the lens 20 into the light-transmitting region of the filter 22 can be directly and unobstructed into the image sensor 23 for imaging. And the interference light is blocked by the light blocking film 222.

The light blocking film 222 can block the interference light incident thereon, but if only the interference light is reflected, the interference light is reflected by multiple components in the camera module, and possibly It is incident on the light-transmitting region, thereby entering the image sensor 23 for imaging, affecting the image quality. Therefore, it is preferable that the interference light incident on the light-blocking film 222 is absorbed to prevent it from being incident on the light-transmitting region again through reflection.

Preferably, the light-blocking film 222 is a black material, which can effectively absorb more than 95% of light energy, less than 0.2% of light energy is transmitted, and less than 3.5% of light energy is reflected. Since the energy transmitted and reflected is relatively small, the energy incident on the effective area of the image sensor 23 through the light blocking film 222 is negligible in consideration of the energy loss in the optical path. Therefore, the light incident on the light-blocking film 222 is substantially blocked by the light-blocking film 222.

In addition, it is worth mentioning that since the black material for manufacturing the light-blocking film 222 is an organic material, it cannot be wiped with an organic solvent such as an acid or an alkali solvent, alcohol or acetone in an actual process, otherwise the light-blocking film may be easily caused. 222 dissolution, dilution, shedding, etc. occurred. Since the light blocking film 222 is a convex type colloid, In the actual process, it is not possible to touch a sharp object, otherwise it will easily cause scratches and the colloid will fall off, which will cause the camera module to leak light.

Figure 6 is a comparison of the filter 22 of the present invention with a conventional filter in actual operation. The upper surface of the filter 22 is provided with the light-blocking film 222, and the conventional filter has no light-blocking film, and the incident light rays shown in the figure form the interference light.

When the interfering light is incident on the edge region of the conventional filter, a part of the light passing through the filter is incident on the inner wall of the bracket 21, and is reflected by the inner wall of the bracket 21 into the image sensor 23, because of this Part of the light is the light that is reflected twice, so it affects the image quality; another part of the light is incident on the surface of the gold wire 25, reflected by the gold wire 25 to the lower surface of the filter, and then subjected to conventional filtering. The reflection of the lower surface of the light sheet enters the image sensor 23, and since this portion of the light is also the light that is reflected multiple times, the image quality is ultimately affected.

When the interference light is incident on the edge region of the filter 22, since the edge region of the filter 22 is covered with the light blocking film 222, the light blocking film 222 blocks the interference light, so that The interfering light cannot pass through the filter 22.

The present invention also provides a method for manufacturing a filter for a camera module, comprising the steps of: (a) providing an annular light blocking film 222 to an infrared cut filter 221 of a camera module to enable the infrared A light transmissive region is formed in the middle of the cut filter 221, and a light blocking region is formed outside the light transmissive region.

Preferably, in step (a), the annular light blocking film 222 is disposed on a surface of the side of the infrared cut filter 221 opposite to the lens 20.

Preferably, before step (a), the method further comprises the steps of:

(b) determining the inner frame size of the light-blocking film 222, so that the light passing through the inner frame of the light-blocking film 222 directly enters an image sensor of the camera module;

(c) determining the outer frame size of the light-blocking film 222 such that the vertical projection of the outer frame of the light-blocking film 222 is within a range of a mounting table 211 on which the filter 22 is mounted.

In the step (b), the method for determining the inner frame size of the light-blocking film 222 includes the following steps:

(b1) simulating an angle between the chief ray, the upper ray, and the lower ray of each field according to the optical path condition of the optical system inside the lens 20;

(b2) obtaining a radius of curvature of a last lens of the lens 20, a distance of the lens 20 to the filter 22, a distance of the filter 22 to the image sensor 23, and the filter 22 refractive index and thickness;

(b3) Calculating the simulated image heights of the chief ray, the upper ray, and the lower ray of each field of view according to the above parameters, and using the maximum simulated image height in each field of view as the size of the fenestration 2221.

Preferably, in step (a), the light blocking film 222 is applied to the infrared cut filter 221 by a yellow light process, and the photoresist in the yellow light process is black absorptive. material.

Preferably, when the light-blocking film 222 is coated by a yellow light process, the method includes the steps of: cleaning and drying the infrared cut filter 221; coating the infrared cut filter 221 on the bottom; The infrared cut filter 221 is spin-coated with a photoresist; the infrared cut filter 221 is soft-baked; the infrared cut filter 221 is aligned and exposed; and the infrared cut filter 221 is post-baked; The infrared cut filter 221 is developed; the infrared cut filter 221 is hard-baked; and the infrared cut filter 221 is etched to form the filter 22.

Preferably, in step (a), the light blocking film 222 is applied to the infrared cut filter 221 by a silk screen process, and the ink in the silk screen process is a black absorbing material.

Preferably, when the light-blocking film 222 is coated by a silk screen process, the method includes the steps of: applying the ink to the infrared cut filter 221 by a screen printing plate; and baking the infrared cut filter 221 The filter 22 is obtained.

Those skilled in the art should understand that the embodiments of the present invention described in the above description and the accompanying drawings are only by way of illustration and not limitation. The object of the invention has been achieved completely and efficiently. The present invention has been shown and described with respect to the embodiments of the present invention, and the embodiments of the present invention may be modified or modified without departing from the principles.

Claims

A camera module, comprising: a lens, a bracket for fixing the lens, a filter disposed under the lens, and an image sensor disposed under the filter, wherein The filter comprises an infrared cut filter and a light blocking film, the light blocking film is disposed on the surface of the infrared cut filter, and the light blocking film has an open window in the middle to enable the infrared cutoff A light transmissive region is formed in the middle of the filter, and a light blocking region is formed outside the light transmissive region.
The camera module of claim 1 , wherein the light blocking film is annular, the inner frame of the light blocking film forms the fenestration, and the light blocking film is along an edge of the infrared cut filter And disposed on an upper surface of the infrared cut filter.
The camera module of claim 2, wherein the inner frame size of the light-blocking film is calculated by calculating a simulation of the chief ray, the upper ray and the lower ray of each field of view according to each parameter of the camera module. The image height is the maximum frame height in each field of view as the inner frame size of the light blocking film.
The camera module as claimed in claim 2, wherein the bracket extends inwardly from a mounting base, a window is formed in the middle of the mounting base, and the filter is mounted on the mounting base, outside the light blocking film The vertical projection of the frame is within the range of the mounting table.
The camera module as claimed in claim 3, wherein the bracket extends inwardly from a mounting base, a window is formed in the middle of the mounting base, and the filter is mounted on the mounting base, outside the light blocking film The vertical projection of the frame is within the range of the mounting table.
The camera module of claim 1 , wherein the light blocking film is applied to the infrared cut filter by a yellow light process or a silk screen process, and the reticle used when the yellow light process is utilized The shape is the same as that of the light-blocking film, and when the screen printing process is utilized, the shape of the ink-permeable region of the screen printing plate used is the same as that of the light-blocking film.
The camera module of claim 5, wherein the light blocking film is applied to the infrared cut filter by a yellow light process or a silk screen process, and the reticle used when the yellow light process is utilized The shape is the same as that of the light-blocking film, and when the screen printing process is utilized, the shape of the ink-permeable region of the screen printing plate used is the same as that of the light-blocking film.
The camera module according to claim 1, wherein the light-blocking film has a thickness of 2 μm to 12 μm.
The camera module according to claim 7, wherein the light-blocking film has a thickness of 2 μm to 12 μm.
The camera module of claim 1 wherein said light blocking film is a black absorbent material The material can absorb more than 95% of the light energy, less than 0.2% of the light energy is transmitted, and less than 3.5% of the light energy is reflected.
The camera module according to claim 9, wherein the light blocking film is a black absorbing material capable of absorbing more than 95% of light energy, less than 0.2% of light energy is transmitted, and less than 3.5% of light energy is reflection.
The camera module of any of claims 1-11, wherein the camera module further comprises a circuit board, and the circuit board and the image sensor are electrically connected by a plurality of gold wires.
A filter, the filter is adapted to be mounted on a camera module, the camera module includes a lens disposed above the filter, a bracket for fixing the lens, and a device disposed at the camera An image sensor under the filter, wherein the filter comprises an infrared cut filter and a light blocking film, and the light blocking film is disposed on the surface of the infrared cut filter, The light blocking film has a window in the middle to form a light transmissive area in the middle of the infrared cut filter, and a light blocking area is formed outside the light transmissive area.
A filter according to claim 13, wherein said light blocking film is annular, an inner frame of said light blocking film forms said fenestration, said light blocking film is along an edge of said infrared cut filter And disposed on an upper surface of the infrared cut filter.
The filter according to claim 14, wherein the inner frame size of the light-blocking film is calculated by calculating a simulation of the chief ray, the upper ray and the lower ray of each field of view according to each parameter of the camera module. The image height is the maximum frame height in each field of view as the inner frame size of the light blocking film.
The filter according to claim 14, wherein the bracket of the camera module extends inwardly from a mounting table, a window is formed in the middle of the mounting base, and the filter is mounted on the mounting platform. The vertical projection of the outer frame of the light-blocking film is within the range of the mounting table.
The filter according to claim 15, wherein the bracket of the camera module extends inwardly from a mounting platform, a window is formed in the middle of the mounting platform, and the filter is mounted on the mounting platform. The vertical projection of the outer frame of the light-blocking film is within the range of the mounting table.
The filter according to claim 13, wherein said light blocking film is applied to said infrared cut filter by a yellow light process or a screen printing process, and said reticle is used when said yellow light process is utilized The shape is the same as that of the light-blocking film, and when the screen printing process is utilized, the shape of the ink-permeable region of the screen printing plate used is the same as that of the light-blocking film.
The filter according to claim 17, wherein said light blocking film is applied to said infrared cut filter by a yellow light process or a screen printing process, and said reticle is used when said yellow light process is utilized The shape is the same as that of the light-blocking film, and when the screen printing process is utilized, the ink-permeable area of the screen printing plate used is The shape is the same as the light blocking film.
The filter according to claim 13, wherein said light-blocking film has a thickness of from 2 μm to 12 μm.
The filter according to claim 19, wherein said light-blocking film has a thickness of from 2 μm to 12 μm.
The filter according to claim 13-21, wherein said light blocking film is a black absorbing material capable of absorbing more than 95% of light energy, less than 0.2% of light energy, and less than 3.5% of light. Can be reflected.
A method for manufacturing a filter for a camera module, characterized in that the method comprises the steps of: (a) providing an annular light blocking film on an infrared cut filter of a camera module to enable the infrared A light transmissive region is formed in the middle of the cut filter, and a light blocking region is formed outside the light transmissive region.
The method according to claim 23, wherein in step (a), the light blocking film is disposed on a surface of the infrared cut filter opposite to a lens of the camera module.
The method according to claim 24, further comprising the steps (b) and/or (c) before the step (a), wherein the step (b) is: determining the inner frame size of the light-blocking film to enable the passage The light blocking the inner frame of the light film directly enters an image sensor of the camera module; step (c) is: determining the outer frame size of the light blocking film, so that the vertical projection of the outer frame of the light blocking film is Within the scope of a mounting station on which the filter is mounted.
The method of claim 25, wherein determining the inner frame size of the light-blocking film in step (b) comprises the steps of:

(b1) simulating an angle between the chief ray, the upper ray, and the lower ray of each field according to the optical path condition of the internal optical system of the lens;

(b2) obtaining a radius of curvature of a last lens of the lens, a distance of the lens to the filter, a distance of the filter to the image sensor, and a refractive index and thickness of the filter ;

(b3) Calculating the simulated image heights of the chief ray, the upper ray, and the lower ray of each field of view according to the above parameters, and using the maximum simulated image height in each field of view as the inner frame size of the light blocking film.
The method according to claim 26, further comprising the step of correcting the size of said window 2221 after said step (b3): (b4) said step obtained in step (b3) according to an assembly offset at the time of the process The size of the window 2221 is increased by a corresponding offset to obtain the corrected size of the window 2221.
The method according to any one of claims 23-27, wherein in step (a), the light-blocking film is applied to the surface of the infrared cut filter by a yellow light process, specifically comprising the steps of: cleaning and Drying the infrared cut filter; coating the bottom on the infrared cut filter; spin coating the photoresist on the infrared cut filter; soft drying the infrared cut filter; and the infrared cut filter The light sheet is subjected to alignment exposure; Performing post-baking on the infrared cut filter; developing the infrared cut filter; performing hard baking on the infrared cut filter; and etching the infrared cut filter to form the filter.
The method of claim 28 wherein said photoresist is a black absorbing material that absorbs more than 95% of the light energy, less than 0.2% of the light energy is transmitted, and less than 3.5% of the light energy is reflected.
The method according to any one of claims 23-27, wherein in step (a), the light-blocking film is applied to the surface of the infrared cut filter by a silk screen process, specifically comprising the steps of: screen printing The plate applies an ink to the infrared cut filter; baking the aforementioned infrared cut filter to obtain the filter.
The method of claim 30 wherein said ink is a black absorbing material that absorbs more than 95% of the light energy, less than 0.2% of the light energy is transmitted, and less than 3.5% of the light energy is reflected.
The method according to claims 23-27, wherein said light blocking film is a black absorbing material, said light blocking film can absorb more than 95% of light energy, less than 0.2% of light energy is transmitted, and less than 3.5. % of the light energy is reflected.