Apparatus and method for assembling a camera module

Abstract

An apparatus (10) for assembling a camera module (15) com- prises a carrier (1009 comprising a first carrier portion (101) for carrying a reference sensor (107) and a second car- rier portion (102) for carrying an assembly sensor (108). The first carrier portion (101) comprises contact elements (109) for electrically connecting contact pads (103) of the refer- ence sensor (107) to terminals (104). The apparatus (10) fur- ther comprises a measuring sensor (110) for determining a spa- tial relationship between the reference sensor (107) and the assembly sensor (108), and an alignment system (123) for aligning a lens module (120) with respect to the reference sensor (107), the alignment system (123) being configured to place the lens module (120) in an aligned position. The appa- ratus (10) further comprises a positioning system (128) for positioning the lens module (120) over the assembly sensor (108), starting from the aligned position and based on the de- termined spatial relationship, and a fixing system (127) for fixing the position of the lens module (120) with respect to the assembly sensor (108).

Description

[0001] APPARATUS AND METHOD FOR ASSEMBLING A CAMERA MODULE

[0002] Assembling processes for assembling a lens module and a sensor to form a camera module usually are performed using an active alignment process. For example, a sensor may be held in a socket and a temporary electrical connection may be formed between a suitable processing device and the sensor to read out information from the sensor when the sensor is e.g. illuminated with a specific illumination pattern. For example, the electrical connection may be made over a PCB ("printed circuit board") or a flex PCB which is already connected to the sensor. With decreasing sensor sizes and camera module sizes, a camera module may be implemented as a chip scale package ("CSP") . In this case, the handling space may be decreased. Accordingly, methods and apparatuses are developed for assembling a camera module.

[0003] It is an object to provide an improved apparatus and an improved method for assembling a camera module.

[0004] According to embodiments, the above object is achieved by the claimed matter according to the independent claims . Further developments are defined in the dependent claims.

[0005] According to embodiments, an apparatus for assembling a camera module comprises a carrier comprising a first carrier portion for carrying a reference sensor and a second carrier portion for carrying an assembly sensor. The first carrier portion comprises contact elements for electrically connecting contact pads of the reference sensor to terminals. The apparatus further comprises a measuring sensor for determining a spatial relationship between the reference sensor and the assembly sensor and an alignment system for aligning a lens module with respect to the reference sensor, the alignment system being configured to place the lens module in an aligned position.

[0006] The apparatus further comprises a positioning system for positioning the lens module over the assembly sensor, starting from the aligned position and based on the determined spatial relationship, and a fixing system for fixing the position of the lens module with respect to the assembly sensor.

[0007] For example, the reference sensor may be configured to be arranged over a first main surface of the first carrier portion and the contact elements may extend from the first main surface to a second main surface of the first carrier portion.

[0008] The alignment system may comprise an illumination device for illuminating the reference sensor via the lens module, and a processing device for processing electrical signals received via the terminals.

[0009] According to embodiments, the alignment system further comprises an adjustment device for placing the lens module in the aligned position.

[0010] For example, the fixing system may comprise a dispenser for applying a glue to a first main surface of the assembly sensor and a curing system for curing the glue after arranging the lens module over the first main surface of the assembly sensor .

[0011] According to embodiments, the alignment system may be further configured to determine a distance between the lens module and the reference sensor. Moreover, the fixing system may be configured to determine a glue volume based on the determined distance . According to embodiments , the second carrier portion comprises a cavity .

[0012] For example, contact elements for electrically connecting contact pads of the assembly sensor may be absent from the second carrier portion .

[0013] According to embodiments , a method for assembling a camera module may comprise placing a reference sensor and an assembly sensor in a fixed spatial relationship, contact pads of the reference sensor being electrically connected to terminals , contact pads of the assembly sensor being disconnected from terminals . The method further comprises determining the spatial relationship between the reference sensor and the assembly sensor, and aligning a lens module with respect to the reference sensor, comprising placing the lens module in an aligned position . The method further comprises positioning the lens module over the assembly sensor, starting from the aligned position and based on the determined spatial relationship, and fixing the position of the lens module with respect to the assembly sensor .

[0014] For example, aligning the lens module with respect to the reference sensor may comprise an active alignment process .

[0015] By way of example , the lens module comprises a plurality of lenses and aligning the lens module comprises aligning each of the plurality of lenses .

[0016] According to embodiments , aligning the lens module may comprise reading out electrical signals from the terminals . For example, fixing the position of the lens module with respect to the assembly sensor may comprise dispensing a glue on the assembly sensor and / or the lens module .

[0017] According to embodiments , aligning the lens module with respect to the reference sensor may comprise determining a distance between the lens module and the reference sensor . Moreover, the glue may be dispensed after determining the distance between the lens module and the reference sensor . The method may further comprise determining a volume of glue needed based on the determined distance .

[0018] BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification . The drawings illustrate the embodiments of the present invention and together with the description serve to explain the principles . Other embodiments of the invention and many of the intended advantages will be readily appreciated, as they become better understood by reference to the following detailed description . The elements of the drawings are not necessarily to scale relative to each other . Like reference numbers designate corresponding similar parts .

[0020] Fig . 1A shows a cross-sectional view of a carrier which forms a component of an apparatus for assembling a camera module .

[0021] Fig . IB shows a perspective view of the carrier .

[0022] Fig . 1C shows perspective views of a reference sensor and an assembly sensor . Fig. ID shows a cross-sectional view of a carrier when the reference sensor and the assembly sensor are placed over the carrier .

[0023] Fig. 2A shows further components of the apparatus when performing further processes.

[0024] Fig. 2B illustrates an offset calculation method.

[0025] Fig. 3A shows further components of the apparatus when performing further processes.

[0026] Fig. 3B shows further components of the apparatus when aligning a lens module.

[0027] Fig. 3C shows components of the apparatus when placing the lens module over the assembly sensor.

[0028] Fig. 3D shows a cross-sectional view of a camera module.

[0029] Fig. 4 summarizes a method according to embodiments.

[0030] DETAILED DESCRIPTION

[0031] In the following detailed description reference is made to the accompanying drawings, which form a part hereof and in which are illustrated by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology such as "top", "bottom", "front", "back", "over", "on", "above", "leading", "trailing" etc. is used with reference to the orientation of the Figures being described. Since components of embodiments of the invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope defined by the claims .

[0032] The description of the embodiments is not limiting . In particular, elements of the embodiments described hereinafter may be combined with elements of di f ferent embodiments .

[0033] The terms " lateral" and "horizontal" as used in this speci fication intends to describe an orientation parallel to a first surface of a substrate or semiconductor body . This can be for instance the surface of a wafer or a die .

[0034] The term "vertical" as used in this speci fication intends to describe an orientation which is arranged perpendicular to the first surface of a substrate or semiconductor body .

[0035] As employed in this speci fication, the terms "coupled" and / or "electrically coupled" are not meant to mean that the elements must be directly coupled together - intervening elements may be provided between the "coupled" or "electrically coupled" elements . The term "electrically connected" may describe a low- ohmic electric connection between the elements electrically connected together .

[0036] Fig . 1A shows components of an apparatus 10 for assembling a camera module . The apparatus 10 comprises a carrier 100 comprising a first carrier portion 101 for carrying a reference sensor and a second carrier portion 102 for carrying an assembly sensor (not shown in Fig . 1A) . Within the present disclosure , the term "assembly sensor" refers to the sensor which is actually to be assembled to the lens module to form the camera module . As is illustrated in Fig. 1A, the first carrier portion 101 comprises contact elements 109 for electrically connecting contact pads 103 of the reference sensor 107 to terminals 104. As is illustrated in Fig. 1A, the reference sensor 107 may be arranged over a first main surface 111 of the carrier 100. The contact elements 109 may extend to a second main surface 112 of the carrier 100. The terminals 104 may be arranged adjacent to the second main surface 112 of the carrier 100. According to further examples, the contact elements 109 may be routed on either side of the carrier 100 or inside the carrier 100 on different layers. For example, the carrier 100 may be implemented as a PCB ("printed circuit board") or as a multilayer PCB. The contact elements 109 may form a fanout to simplify the electrical connection .

[0037] Fig. IB shows a perspective view of the carrier 100. As is shown, the second carrier portion 102 may e.g. form a cavity or a pocket within the carrier 100. Furthermore, the contact elements 109 extend from the first main surface 111 to the second main surface 112 of the carrier.

[0038] Fig. 1C shows perspective views of a reference sensor 107 and of an assembly sensor 108. For example, contact pads 103 may be formed ad acent to a second main surface 116 of the reference sensor 107. The first main surface 117 of the reference sensor 107 may be light-receiving surface and may comprise sensor elements for detecting incident electromagnetic radiation. The structure of the assembly sensor 108 may be identical with the structure of the reference sensor 107. In a similar manner as shown in the left-hand part of Fig. 1C, the assembly sensor 108 may comprise contact pads 105 that are arranged on a second main surface 119 of the assembly sensor 108. The first main surface 118 of the assembly sensor 108 may be a light-receiving surface. The contact pads 103 of the reference sensor may be electrically connected to components of the reference sensor 107. In a corresponding manner, the contact pads 105 of the assembly sensor 108 may be electrically connected to components of the assembly sensor 108. For example, the contact pads may be connected to light-receiving elements, e.g. diodes, and may be configured to measure a current as a signal of received electromagnetic radiation .

[0039] Fig. ID shows a cross-sectional view of the carrier 100 when the reference sensor 107 and the assembly sensor 108 are mounted over the carrier 100. As is shown, the contact pads 105 of the assembly sensor are not connected to any contact element within the second carrier portion 102, e.g. within the cavity. For example, the assembly sensor 108 may be held in position due to a vacuum inside the apparatus 10. As a consequence, the assembly sensor 108 may be easily removed from the carrier 100 without disconnecting any electrical contact to the contact pads 105. The reference sensor 107 is electrically connected to the terminals 104 via the contact elements 109 and the contact pads 103. The reference sensor 107 is a stationary sensor which remains connected to the terminals 104 after finishing the assembly process. The assembly sensor 108 is placed on the carrier 100 and is to remain in a fixed spatial relationship to the reference sensor 107.

[0040] As is illustrated in Fig. 2A, the apparatus 10 for assembling a camera module further comprises a measuring sensor 110 which is configured to determine a spatial relationship between the reference sensor 107 and the assembly sensor 108. For example, the measuring sensor 110 may be an interferometer, an autocollimator, chromatic white light sensor and others. The measuring sensor 110 may be configured to determine a position of the reference sensor 107 and of the assembly sensor 108. Figure 2B illustrates the process of calculation an offset between the reference sensor plane 113 and the assembly sensor plane 114 .

[0041] The apparatus 10 for assembling a camera module further comprises a fixing system 127 for fixing the position of a lens module (not illustrated in Fig . 3A) to the assembly sensor 108 . Fig . 3A shows components of the fixing system 127 which may comprise a dispenser 124 for applying glue 125 to the assembly sensor 108 . As has to be noted, the glue 125 may be applied to the assembly sensor 108 at any suitable stage of the process . According to further implementations , the glue 125 may also or alternatively be applied to the lens module 120 that is to be attached to the assembly sensor 108 .

[0042] The apparatus 10 for assembling a camera module further comprises an alignment system 123 for aligning a lens module 120 with respect to the reference sensor 108 . As is illustrated in Fig . 3B, the alignment system 123 comprises an illumination device 121 for illuminating the reference sensor 107 via the lens module 120 and a processing device 122 for processing electrical signals received via the terminals 104 . For example, the illumination device 121 may be configured to generate an illumination pattern which may be detected by evaluating signals detected by the reference sensor 107 . The signals may be read out by the processing device 122 via the terminals 104 . The alignment system 123 may further comprise an adj ustment device 115 for changing the position of the lens module 120 over the reference sensor 107 . As a consequence, the lens module may be placed in an aligned position .

[0043] For example , the adj ustment device 115 may change a tilt angle of the lens module 120 with respect to the reference sensor 107 and may change the position in a horizontal or vertical direction with respect to the reference sensor 107 . The functionality and construction of the adj ustment device 115 and of the alignment system 123 may be similar to those employed in known apparatuses performing an active alignment of components of a camera module .

[0044] For example, a distance between the lens module 120 and the reference sensor 107 may be determined during the alignment of the lens module 120 with respect to the reference sensor 107 . For example, when the glue is dispensed after determining the distance between the lens module 120 and the reference sensor 107 , a volume of glue needed may be determined based on the determined distance . For example, the fixing system 127 may be configured to determine a glue volume based on the determined distance .

[0045] As a consequence glue overspill may be avoided .

[0046] After aligning the lens module 120 with respect to the reference sensor 107 which may comprise adj usting the position using adj ustment device 115 , the lens module 120 may be moved to the assembly sensor 108 using a positioning system 128 . In more detail , the lens module 120 may be positioned over the assembly sensor 108 , starting from the aligned position .

[0047] As is illustrated in Fig . 3C, the positioning system 128 positions the lens module 120 over the assembly sensor 108 based on the determined spatial relationship that has been explained above referring to Fig . 2B . In other words , the of fset calculated in a manner as was described with reference to Fig . 2B, is added to the spatial coordinates adj usted by the adj ustment device 115 and a corresponding positioning is performed by the positioning system 128 . Thereafter, the position of the lens module 120 with respect to the assembly sensor 108 is f ixed . For example , this may comprise curing the glue 125 , e . g . using a curing system 126. For example, the curing system 126, e.g. which may perform UV exposure may be a component of the fixing system 127.

[0048] Fig. 3D shows an example of a camera module 15 that may be obtained using the apparatus 10 or the method described. The camera module comprises an assembly sensor 108 and a lens module 120 arranged over and aligned with the assembly sensor 108.

[0049] For example, the size of the assembly sensor 108 may be less than 10 mm or even less than 1 mm.

[0050] Fig. 4 summarizes a method according to embodiments. As is shown, a method for assembling a camera module comprises placing (S100) a reference sensor and an assembly sensor in a fixed spatial relationship, contact pads of the reference sensor being electrically connected to terminals, contact pads of the assembly sensor being disconnected from terminals. The method further comprises determining (S110) the spatial relationship between the reference sensor and the assembly sensor, and aligning (S120) a lens module with respect to the reference sensor, comprising placing the lens module in an aligned position. The method further comprises positioning (S130) the lens module over the assembly sensor, starting from the aligned position and based on the determined spatial relationship, and fixing (S140) the position of the lens module with respect to the assembly sensor.

[0051] As has been shown, due to the method described, the positioning of the lens module over the sensor may be implemented in a fast and easy manner. Since there is no need to disconnect the contact pads 105 after mounting the lens module 120, the risk of improper contacting, destruction of components may be eliminated. Moreover, since the reference sensor 107 is powered up to perform measurements, the need to temporarily connect and power up the assembly sensor 108 may be avoided . As a further consequence, time may be saved and the throughput of the system may be improved . Moreover, the described process enables the assembly of camera modules having further reduced sensor si zes . For example, the described camera module may be a micro camera, e . g . for use in a mobile phone .

[0052] While embodiments of the invention have been described above , it is obvious that further embodiments may be implemented . For example , further embodiments may comprise any subcombination of features recited in the claims or any subcombination of elements described in the examples given above . Accordingly, this spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein .

[0053] LIST OF REFERENCES apparatus for assembling a camera module camera module carrier first carrier portion second carrier portion contact pad of reference sensor terminal contact pad of assembly sensor reference sensor assembly sensor contact element measuring sensor first main surface of carrier second main surface of carrier reference sensor plane assembly sensor plane adjustment device second main surface of reference sensor first main surface of reference sensor first main surface of assembly sensor second main surface of assembly sensor lens module illumination device processing device alignment system dispenser glue curing system fixing system positioning system

Claims

CLAIMS1. An apparatus (10) for assembling a camera module (15) comprising : a carrier (1009 comprising a first carrier portion (101) for carrying a reference sensor (107) and a second carrier portion (102) for carrying an assembly sensor (108) , the first carrier portion (101) comprising contact elements (109) for electrically connecting contact pads (103) of the reference sensor (107) to terminals (104) , a measuring sensor (110) for determining a spatial relationship between the reference sensor (107) and the assembly sensor (108) , an alignment system (123) for aligning a lens module (120) with respect to the reference sensor (107) , the alignment system (123) being configured to place the lens module(120) in an aligned position, a positioning system (128) for positioning the lens module (120) over the assembly sensor (108) , starting from the aligned position and based on the determined spatial relationship, and a fixing system (127) for fixing the position of the lens module (120) with respect to the assembly sensor (108) .

2. The apparatus (10) according to claim 1, wherein the reference sensor (1079 is configured to be arranged over a first main surface (111) of the first carrier portion (101) and the contact elements (109) extend from the first main surface (111) to a second main surface (112) of the first carrier portion ( 101 ) .

3. The apparatus (10) according to claim 1 or 2, wherein the alignment system (123) comprises an illumination device(121) for illuminating the reference sensor (107) via the lensmodule (120) , and a processing device (122) for processing electrical signals received via the terminals (104) .

4. The apparatus (10) according to any of the preceding claims, wherein the alignment system (123) further comprises an adjustment device (115) for placing the lens module (120) in the aligned position.

5. The apparatus (10) according to any of the preceding claims, wherein the fixing system (127) comprises a dispenser (124) for applying a glue (125) to a first main surface of the assembly sensor (108) and a curing system (126) for curing the glue (125) after arranging the lens module (120) over the first main surface of the assembly sensor (108) .

6. The apparatus (10) according to claim 5, wherein the alignment system (115) further is configured to determine a distance between the lens module (120) and the reference sensor (107) and the fixing system is configured to determine a glue volume based on the determined distance.

7. The apparatus (10) according to any of the preceding claims, wherein the second carrier portion (102) comprises a cavity.

8. The apparatus (10) according to any of the preceding claims, wherein contact elements for electrically connecting contact pads (105) of the assembly sensor (108) are absent from the second carrier portion (102) .

9. A method for assembling a camera module (15) , comprising : placing a reference sensor (107) and an assembly sensor (108) in a fixed spatial relationship, contact pads (103) ofthe reference sensor (107) being electrically connected to terminals (104) , contact pads (105) of the assembly sensor (108) being disconnected from terminals, determining the spatial relationship between the reference sensor (107) and the assembly sensor (108) , aligning a lens module (120) with respect to the reference sensor (107) , comprising placing the lens module (120) in an aligned position, positioning the lens module (120) over the assembly sensor (108) , starting from the aligned position and based on the determined spatial relationship, and fixing the position of the lens module (120) with respect to the assembly sensor (108) .

10. The method according to claim 9, wherein aligning the lens module (120) with respect to the reference sensor (107) comprises an active alignment process.

11. The method according to claim 9 or 10, wherein the lens module (120) comprises a plurality of lenses and aligning the lens module (120) comprises aligning each of the plurality of lenses .

12. The method according to any of claims 9 to 11, wherein aligning the lens module (120) comprises reading out electrical signals from the terminals (104) .

13. The method according to any of claims 9 to 12, wherein fixing the position of the lens module (120) with respect to the assembly sensor (108) comprises dispensing a glue on the assembly sensor (108) and / or the lens module (120) .

14. The method according to claim 13, wherein aligning the lens module (120) with respect to the reference sensor (107)comprises determining a distance between the lens module (120) and the reference sensor (107) , and the glue is dispensed after determining the distance between the lens module (120) and the reference sensor (107) , the method further comprising de- termining a volume of glue needed based on the determined distance .

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