CN112399042B - Camera module and its calibration method - Google Patents

Abstract

The present invention provides a camera module, comprising a substrate, a sensing chip, a lens assembly and a piezoelectric sheet, the sensing chip is electrically connected to the substrate and has a sensing area, and the lens assembly covers the substrate so that the sensing chip is located between the substrate and the lens assembly, The piezoelectric sheet is disposed between the substrate and the lens assembly, and deforms after being powered, so that the lens assembly focuses on the sensing area of the sensing chip. In addition, the present invention also provides a calibration method for the above-mentioned camera module.

Description

Camera module and its calibration method

technical field

The invention relates to the field of optics, in particular to a camera module and a calibration method thereof.

Background technique

In recent years, with the evolution of the electronic industry and the vigorous development of industrial technology, the design and development of various electronic devices are gradually developing towards the direction of lightness and portability, so that users can use them in mobile business, entertainment or leisure anytime and anywhere. use. For example, various camera modules are widely used in various fields, such as smart phones, wearable electronic devices and other portable electronic devices. They have the advantages of small size and easy portability, and people can use them when they need it. It can be taken out at any time for image extraction and storage, or further uploaded to the Internet through the mobile network, which not only has important commercial value, but also adds color to the daily life of the general public.

Please refer to FIG. 1 and FIG. 2. FIG. 1 is a schematic diagram of the appearance structure of a conventional camera module, which is also a camera module 1 proposed by the applicant of the present invention in Taiwan Patent Application No. TW106130015, and FIG. 2 is the camera shown in FIG. 1. Side view conceptual diagram of the module. The camera module 1 includes a substrate 11 , a sensor chip 12 and a lens assembly 13 , and the lens assembly 13 includes a fixing frame 131 and a lens module 132 disposed on the fixing frame 131 , and the lens module 132 is composed of a plurality of optical lenses, and any one of the optical lenses is formed. The optical lens can be a plastic lens or a glass lens; wherein, the sensing chip 12 is disposed on the upper surface 111 of the substrate 11 and is electrically connected to the substrate 11 , and the fixing frame 131 covers the sensing chip 12 so that the sensing chip 12 is located in the lens assembly 13 and between the substrate 11 . According to the above structure of the camera module 1 , when the external light beams pass through the lens module 132 and the fixing frame 131 in sequence, they are projected onto the sensing chip 12 , so the sensing chip 12 can generate a corresponding image.

Furthermore, during the assembly process of the camera module 1, a thermosetting adhesive 14 is disposed between the fixing frame 131 of the lens assembly 13 and the substrate 11. After the thermosetting adhesive 14 is baked, the lens assembly 13 and the substrate 11 can be in contact with each other. In combination, the sensor chip 12 is completely sealed between the lens assembly 13 and the substrate 11 , thereby preventing external particles from entering the camera module 1 and affecting the travel of the light beam, and also preventing the unintended external light beam from entering the camera module 1 . stray light.

However, the applicant has found that the camera module 1 is often out of focus, so that the sensor chip 12 cannot obtain a clear image. The reason is that the due distance between the lens module 132 and the sensor chip 12 is changed. The factors that make the lens module 132 unable to accurately focus on the sensing chip 12 and the distance between the lens module 132 and the sensing chip 12 are changed include: first, the thermosetting glue 14 will have uncontrollable glue after baking Second, different optical lenses in the lens module 132 have different expansion and contraction ratios for the same temperature environment because they are composed of different materials. However, since most of the existing camera modules used in portable electronic devices or automotive electronic devices adopt a fixed-focus structure, once the camera module 1 is out of focus, the focal length of the lens module 132 cannot be changed. Therefore, the imaging quality of the camera module 1 cannot be improved. From the above description, the known camera module has room for improvement.

SUMMARY OF THE INVENTION

A first objective of the present invention is to provide a camera module that utilizes the deformation of the piezoelectric sheet so that the distance between the lens module and the sensing chip always conforms to the focal length of the lens module during the imaging process, thereby overcoming the problems in the prior art. The described running focus situation. Since the piezoelectric sheet has the advantages of good control accuracy and small size, the camera module of the present invention is suitable for being installed in portable electronic devices and automotive electronic devices, and is more conducive to the orientation of portable electronic devices and automotive electronic devices. Light, thin, and short.

A second object of the present invention is to provide a camera module calibration method applied to the above-mentioned camera module.

In a preferred embodiment, the present invention provides a camera module, which includes a substrate, a sensor chip, a lens assembly, and a piezoelectric sheet. A sensing chip is electrically connected to the substrate and has a sensing area; a lens assembly covers the sensing chip so that the sensing chip is located between the substrate and the lens assembly; wherein, when the external light beam passes through the lens assembly and is projected to the In the sensing area, the sensing chip generates an image; a piezoelectric sheet is arranged between the substrate and the lens assembly, and deforms after being powered to make the lens assembly focus on the sensing area.

In a preferred embodiment, the present invention also provides a method for calibrating a camera module, which is applied to a camera module. The camera module includes a substrate, a sensor chip electrically connected to the substrate, and a sensor chip that covers the sensor chip. The sensing chip is located in a lens assembly between the substrate and the lens assembly and a piezoelectric sheet disposed between the substrate and the lens assembly, wherein the calibration method of the camera module includes:

When an interval distance between a lens module of the lens assembly and the sensing chip does not conform to a focal length of the lens module, the distance between the lens module and the sensing chip is obtained for driving the piezoelectric sheet to deform. The separation distance corresponds to an electric power value of the focal length of the lens module; the electric power value is stored; and the electric power value is provided to the piezoelectric sheet when the camera module performs imaging.

The beneficial effect of the present invention is that the present invention is provided with a piezoelectric sheet in the camera module that is micro-deformed according to actual application conditions, so that the distance between the lens module and the sensing chip is always consistent with the lens module during the shooting process of the camera module. Therefore, the camera module can capture a clear image and effectively overcome the defocusing situation described in the prior art.

Description of drawings

FIG. 1 is a schematic diagram of the appearance structure of a conventional camera module.

FIG. 2 is a conceptual schematic side view of the camera module shown in FIG. 1 .

FIG. 3 is a schematic diagram of a preferred appearance structure of the camera module of the present invention.

FIG. 4 is a schematic exploded perspective view of a partial structure of the camera module shown in FIG. 3 .

FIG. 5 is a conceptual schematic side view of a partial structure of the camera module shown in FIG. 3 .

FIG. 6 is a schematic block diagram of a preferred process flow of the calibration method of the camera module of the present invention.

The reference numbers are as follows:

1 camera module

2 camera modules

11 substrates

12 induction chips

13 Lens Components

14 Thermosetting glue

21 substrate

22 induction chip

23 Lens Components

24 colloids

25 Piezoelectric Pieces

26 driver chips

27 memory

111 The upper surface of the substrate

131 Fixture

132 lens modules

222 sensing area

231 Fixture

232 lens module

S1 step

S2 step

S3 step

Detailed ways

Embodiments of the present invention will be further explained below in conjunction with the related drawings. Wherever possible, in the drawings and the description, the same reference numbers refer to the same or similar components. In the drawings, shapes and thicknesses may be exaggerated for simplicity and convenience. It should be understood that elements not particularly shown in the drawings or described in the specification are in the form known to those skilled in the art. Those skilled in the art can make various changes and modifications based on the content of the present invention.

Please refer to FIGS. 3 to 5 . FIG. 3 is a schematic diagram of a preferred appearance structure of the camera module of the present invention, FIG. 4 is a perspective exploded schematic diagram of a partial structure of the camera module shown in FIG. 3 , and FIG. 5 is a schematic diagram of the camera module shown in FIG. 3 . Side view conceptual diagram of part of the structure. The camera module 2 includes a substrate 21 , a sensing chip 22 , a lens assembly 23 , a piezoelectric sheet 25 , a driving chip 26 and a memory 27 , the sensing chip 22 has a sensing area 222 , and the sensing chip 22 , the driving chip 26 , and the memory 27 are all disposed on the substrate The upper surface of 21 is electrically connected to the substrate 21, and the lens assembly 23 includes a fixing frame 231 and a lens module 232 arranged on the fixing frame 231, wherein the lens module 232 includes at least one optical lens (not shown), and is fixed The frame 231 covers the sensing chip 22 so that the sensing chip 22 is located between the lens assembly 23 and the substrate 21 .

According to the structure of the camera module 2, when the external light beam (not shown in the figure) passes through the lens assembly 23, it will be projected onto the sensing area 222 of the sensing chip 22, so the sensing chip 22 can generate a corresponding image, which is used by the substrate 21 for subsequent processing. signal processing. In this preferred embodiment, the substrate 21 can be a flexible circuit board, a rigid-flex board, a copper foil substrate or a ceramic substrate (Ceramic Substrate), and the lens assembly 23 is a fixed focus lens assembly, but Not limited to the above.

Furthermore, the piezoelectric sheet 25 is disposed between the substrate 21 and the lens assembly 23 , and the upper surface and the lower surface of the piezoelectric sheet 25 are respectively connected to the lens assembly 23 and the substrate 21 . Preferably, but not limited to this, the piezoelectric sheet 25 is a piezoelectric ceramic sheet or a piezoelectric fiber composite (MFC), which is hollow and surrounds the sensing chip 22, and the piezoelectric sheet 25 is The upper surface can be connected to the lens assembly 23 through the glue 24 disposed on the periphery of the upper surface, and the lower surface of the piezoelectric sheet 25 can be connected to the substrate 21 through surface adhesive technology or glue (not shown).

In addition, the driving chip 26 is electrically connected between the substrate 21 and the piezoelectric sheet 25 , and is mainly used for supplying power to the piezoelectric sheet 25 to drive the piezoelectric sheet 25 to deform, and furthermore, the connection between the lens module 232 and the sensing chip 22 is affected. Correct the separation distance between them. In detail, in order to allow the camera module 2 to obtain a clear image, the distance between the lens module 232 and the sensing chip 22 should be consistent with the focal length of the lens module 232. The configured spacing distance between the lens module 232 and the sensor chip 22 is changed due to various factors, such as: the shrinkage phenomenon of the glue 24 after the baking process, or the difference in the lens module 232. The optical lenses of the optical lenses are composed of different materials and have different expansion and contraction ratios for the same temperature environment; therefore, the present invention uses the deformation of the piezoelectric sheet 25 to change the distance between the lens module 232 and the sensing chip 22. The distance between the lens module 232 and the sensing chip 22 is made consistent with the focal length of the lens module 232 , so that the lens module 232 can accurately focus on the sensing area 222 of the sensing chip 22 .

Further, the present invention also provides a calibration method for the camera module 2 as follows. Please refer to FIG. 6 , which is a schematic block diagram of a preferred process flow of the calibration method of the camera module of the present invention. First, when the distance between the lens module 232 and the sensing chip 22 does not conform to the focal length of the lens module 232 , it is obtained to drive the piezoelectric sheet 25 to deform so that the distance between the lens module 232 and the sensing chip 22 conforms to the lens A power value (such as a voltage value) of the focal length of the module 232 is shown in step S1. Next, the power value is stored, as shown in step S2; in one embodiment, the above steps S1 and S2 are performed before the camera module 2 is manufactured and shipped, and the power value obtained in step S1 is stored in the camera module 2 of the memory 27, such as electronically erasable rewritable read only memory (EEPROM). Finally, when the camera module 2 is capturing images, the power value is provided to the piezoelectric sheet 25, as shown in step S3, that is to say, when the camera module 2 is capturing images, the power value can be provided according to the power value stored in the memory 27. The pre-compression sheet 25 makes the distance between the lens module 232 and the sensing chip 22 conform to the focal length of the lens module 232 .

According to the above description, in the present invention, a piezoelectric sheet that can be deformed slightly according to actual application conditions is arranged in the camera module, so that the distance between the lens module and the sensing chip always conforms to the focal length of the lens module during the imaging process of the camera module. , so that the camera module can capture a clear image, effectively overcoming the defocus situation described in the prior art. Since the piezoelectric sheet has the advantages of good control accuracy and small size, the camera module of the present invention is suitable for being installed in portable electronic devices and automotive electronic devices, and is more conducive to the orientation of portable electronic devices and automotive electronic devices. Light, thin, and short.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the claims of the present invention. Therefore, all other equivalent changes or modifications made without departing from the spirit disclosed in the present invention shall be included in the present invention. within the claims.

Claims (11)

1. A camera module, comprising: a substrate; a sensing chip electrically connected to the substrate and having a sensing area; a lens assembly covering the sensing chip so that the sensing chip is located between the substrate and the lens assembly; wherein, when an external light beam passes through the lens assembly and is projected onto the sensing area, the sensing chip generates an image; and a piezoelectric sheet, disposed between the substrate and the lens assembly, and deformed after being powered to make the lens assembly focus on the sensing area; The lens assembly includes a fixing frame and a lens module, and the lens module is disposed on the fixing frame and includes at least one optical lens, the piezoelectric sheet includes an upper surface and a lower surface, and the upper surface and the lower surface respectively connected to the fixing frame and the substrate, and the upper surface of the piezoelectric sheet is connected to the fixing frame through a glue. 2. The camera module of claim 1, wherein the piezoelectric sheet is a piezoelectric ceramic sheet or a piezoelectric fiber sheet. 3. The camera module of claim 1, wherein the lens assembly is a fixed focus lens assembly. 4. The camera module of claim 1, further comprising a driving chip, and the driving chip is electrically connected between the substrate and the piezoelectric sheet; wherein, when the driving chip provides power to the piezoelectric sheet , the piezoelectric sheet is deformed. 5 . The camera module of claim 1 , wherein the lower surface of the piezoelectric sheet is connected to the substrate through a surface adhesive technique, or the lower surface is connected to the substrate through a glue. 6 . 6 . The camera module of claim 1 , wherein the piezoelectric sheet is hollow and surrounds the sensing chip. 7 . 7 . The camera module of claim 1 , wherein the substrate is a flexible circuit board, a rigid-flex composite board, a copper foil substrate or a ceramic substrate. 8 . 8. The camera module of claim 1, further comprising a memory, and the memory stores a power value for supplying power to the piezoelectric sheet. 9 . The camera module of claim 1 , disposed in a portable electronic device or a vehicle electronic device. 10 . 10. A method for calibrating a camera module, applied to a camera module, the camera module comprising a substrate, a sensor chip electrically connected to the substrate, covering the sensor chip so that the sensor chip is located between the substrate and the lens assembly A lens assembly therebetween and a piezoelectric sheet disposed between the substrate and the lens assembly, the lens assembly includes a fixing frame and the lens module, and the lens module is arranged on the fixing frame and includes at least one optical lens, and the piezoelectric sheet includes an upper surface and a lower surface, and the upper surface and the lower surface are respectively connected to the fixing frame and the substrate, and the upper surface of the piezoelectric sheet is connected to the fixing frame through a glue , wherein the calibration method of the camera module includes: When an interval distance between the lens module of the lens assembly and the sensing chip does not conform to a focal length of the lens module, the distance between the lens module and the sensing chip is obtained to drive the piezoelectric sheet to deform. a power value whose separation distance corresponds to the focal length of the lens module; store the power value; and When the camera module is taking pictures, the electric power value is provided to the piezoelectric sheet. 11. The calibration method of the camera module as claimed in claim 10, wherein the power value is stored in a memory of the camera module.

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