Camera module for a motor vehicle and method of mounting a camera module

• US 10,054,757 B2
• Filed: 05/07/2014
• Issued: 08/21/2018
• Est. Priority Date: 09/03/2013
• Status: Active Grant

• Current Assignee: Magna Electronics Sweden AB (SSW Partners LP)
• Original Assignee: Veoneer Sweden AB (SSW Partners LP)
• Inventors: Knutsson, Per, Fredriksson, Peter
• Primary Examiner(s): Dang, Hung
• Assistant Examiner(s): Wendmagegn, Girumsew
• Application Number:
  US14/912,790
• Publication Number:
  US 20160202443A1
• Time in Patent Office: 1,567 Days
• CPC Class Codes: B60R 11/04 Mounting of cameras operative during drive; Arrangement of controls thereof relative to the vehicle
• CPC Class Codes: G02B 7/028 with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation
• CPC Class Codes: H04N 23/51 Housings
• CPC Class Codes: H04N 23/54 Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof
• CPC Class Codes: H04N 23/57 Mechanical or electrical details of cameras or camera modules specially adapted for being embedded in other devices

Abstract

A motor vehicle camera module (12) having a lens assembly (20), a housing (22) forming a front end (50) surrounding an opening (28), an image sensor (24) carried by a back wall (32) within the housing (22) adjacent an image plane (A). The housing (22) having a lens holder (53) between the front end (50) and the back wall (32). The camera module (12) has a tube (26) fixed to the lens holder (53) at the front end (50). The tube (26) surrounds the opening (28) and extends from the opening (28) into the housing (22). The lens assembly (20) is connected to a tube bottom end section by threads (71, 72). The thermal expansion coefficient of the tube (26) is higher than that of the lens holder (53). The threads (71, 72) extends over less than half of the axial length (h_L) of the lens assembly (20).

Claims

1. A camera module for a motor vehicle, comprising a lens assembly, a housing having a back wall and a front end surrounding an opening, and an image sensor carried by the back wall and arranged within the housing in or close to an image plane of the lens assembly, the housing comprising a lens holder extending between the front end and the back wall, the camera module further comprising a tube which is fixed to the lens holder at the front end such that the tube surrounds the opening and extends from the opening into the housing, wherein the lens assembly is connected to a bottom end section of the tube by a connection, and wherein a thermal expansion coefficient of the tube is higher than a thermal expansion coefficient of the lens holder, the connection extending over less than half of the axial length of the lens assembly.

2. The camera module as claimed in claim 1, further comprising in that the thermal expansion coefficient of the lens holder and the thermal expansion coefficient of the tube are adapted to keep the image plane in a predetermined relation to the sensor.

3. The camera module as claimed in claim 1 further comprising in that the thermal expansion coefficient of the tube is adapted such that the tube is able to compensate the thermal expansion of the lens holder and a shift of the image plane caused by changes of the lens assembly.

4. The camera module as claimed in, claim 1 further comprising in that the thermal expansion coefficient of the tube and a height hT of the tube are adapted according to the equation

h_T·

C_T=h_H·

C_H−

Δ

d₂/Δ

T

wherein hH and C_H represent the height and the thermal expansion coefficient of the lens holder, respectively and Δ

d2 represents a change of distance between the lens assembly and the image plane with temperature change Δ

T caused by changes of the lens assembly.

5. The camera module as claimed in claim 1 further comprising in that the material of the lens holder is different from the material of the tube.

6. The camera module as claimed in claim 1 further comprising in that the lens holder is made of a glass fiber reinforced plastic.

7. The camera module as claimed in claim 1 further comprising in that the tube is made of a glass bead reinforced plastic.

8. The camera module as claimed in claim 1 further comprising in that the lens assembly comprises a lens barrel made of a metal.

9. The camera module as claimed in claim 1 further comprising in that the lens assembly comprises lens spacers made of a metal.

10. The camera module as claimed in claim 1 further comprising in that the lens assembly comprises a flange for abutment of the lens assembly against the tube.

11. The camera module as claimed in a claim 1 further comprising in that the tube comprises a flange for abutment of the tube against the lens holder.

12. The camera module as claimed in claim 1 further comprising in that the tube comprises outer threads and the lens holder comprises cooperating inner threads.

13. A camera module as claimed in claim 1 wherein the lens assembly is adapted to be screwed into the tube from below, and the unit of lens assembly and tube is adapted to be screwed into the lens holder from above.

14. A camera module as claimed in claim 1 further comprising the connection in the form of cooperating inner and outer threads.