Placement method for circuit carrier and circuit carrier

Abstract

The invention concerns a process for the production of a circuit carrier (1) equipped with at least one surface-mount LED (SMD-LED), wherein the at least one SMD-LED (2) is positioned in oriented relationship to one or more reference points (3) of the circuit carrier (1) on the circuit carrier (1), wherein the position of a light-emitting region (4) of the at least one SMD-LED (2) is optically detected in the SMD-LED (2) and the at least one SMD-LED (2) is mounted to the circuit carrier (1) in dependence on the detected position of the light-emitting region (4) of the at least one SMD-LED (2), and such a circuit carrier (1).

Claims

1. A process for the production of a circuit carrier equipped with at least one surface-mount LED (SMD-LED) for a motor vehicle, wherein the at least one SMD-LED is positioned in oriented relationship to one or more reference points of the circuit carrier on the circuit carrier, wherein a position of a light-emitting region of the at least one SMD-LED is optically detected in the SMD-LED by illuminating the SMD-LED with a light source that is separate from the SMD-LED, and wherein the at least one SMD-LED is mounted to the circuit carrier in dependence on the detected position of the light-emitting region of the at least one SMD-LED.

2. A process according to claim 1, wherein the position of the light-emitting region is determined in all three dimensions (X, Y, Z) and an angular position is determined relative to an axis of rotation at a right angle to a plane of the SMD-LED.

3. A process according to claim 1, wherein mounting of the at least one SMD-LED to the circuit carrier is affected in dependence on the position of a centre point of the light-emitting region of the at least one SMD-LED.

4. A process according to claim 1, wherein at least one of the one or more reference points is used for positioning an optical system for the at least one SMD-LED.

5. A process according to claim 1, wherein a wavelength of the light source ranges from 400 nm to 500 nm.

6. A process according to claim 1, wherein for mounting the at least one SMD-LED to the circuit carrier, silver sintering material is arranged at the at least one SMD-LED after orientation has been affected, and the at least one SMD-LED is sintered on to the circuit earner.

7. A process according to claim 6, wherein the silver sintering material has a particle size of less than about 100 nm.

8. A process according to claim 7, wherein the silver sintering material is selected with a particle size in a range of about 20 nm to about 40 nm.

9. A process according to claim 1, wherein mounting the at least one SMD-LED to the circuit carrier comprises: applying solder paste to the circuit carrier: applying an adhesive to the circuit carrier; partially hardening the adhesive after positioning the at least one SMD-LED on the circuit carrier; and reflow soldering the solder paste.

10. A process according to claim 4, wherein the at least one of the one or more reference points is used for fixing the optical system for the at least one SMD-LED.

11. A process according to claim 6, wherein for the mounting the at least one SMD-LED to the circuit carrier, the silver sintering material is arranged at the at least one SMD-LED after the orientation has been affected, and the at least one SMD-LED is sintered upon and/or by pressing the at least one SMD-LED on to the circuit carrier.

12. A process according to claim 7, wherein the particle size of the silver sintering material is less than about 60 nm.

13. A process according to claim 9, wherein the solder paste is applied to the circuit carrier by printing thereon, and the adhesive is applied to the circuit carrier in dependence on the detected position of the light-emitting region of the at least one SMD-LED.

14. A process according to claim 1, wherein a wavelength of the light source ranges from 420 nm to 490 nm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a test layout which serves to check the positional accuracy of each individual SMD-LED.

(2) FIG. 2 shows a test layout which serves to check the positional accuracy of each individual SMD-LED.

(3) FIG. 3 shows a test layout which serves to check the positional accuracy of each individual SMD-LED.

(4) FIG. 4a shows a process according to the invention.

(5) FIG. 4b shows a process according to the invention.

(6) FIG. 4c shows a process according to the invention.

DETAILED DESCRIPTION

(7) FIGS. 1 to 3 show test layouts which serve to check the positional accuracy of each individual SMD-LED 2. The circuit carrier 1 has electrically conductive surfaces 5 which are insulated from each other by insulating regions 6. The conductive surfaces 5 can be supplied with electric power by way of terminals 7.

(8) FIG. 1 shows a circuit carrier 1 equipped with six SMD-LEDs 2. It is possible to see two reference points 3 which on the one hand serve to ascertain the deviation of the target positions for the SMD-LEDs 2 on the circuit carrier 1 and which on the other hand can also be used for fixing an optical system (not shown) for the SMD-LEDs 2. The optical system is oriented by way of separate reference points which are not shown in this Figure.

(9) In FIG. 1 the mounting operation was effected with a Pick & Place and Reflow soldering process in accordance with the state of the art. In themselves the SMD-LEDs 2 are oriented by means of their outside contours relative to the reference points 3. The Reflow soldering process involves blurring of the position of the SMD-LEDs 2 so that the situation no longer involves an ordered orientation of the outside contours of the SMD-LEDs 2. Orientation in relation to the light-emitting regions 4 of the SMD-LEDs 2 has not occurred at all.

(10) FIG. 2 shows a circuit carrier 1 equipped with six SMD-LEDs 2, the difference in relation to FIG. 1 being that the SMD-LEDs 2 are mounted on the circuit carrier 1 in the correct position in relation to the outside contour, but no mounting is effected in dependence on the light-emitting regions 4 of the SMD-LEDs 2. This circuit carrier 1 also does not meet the requirements in regard to positioning accuracy of the light-emitting regions 4.

(11) FIG. 3 in contrast shows an embodiment by way of example of the invention in which the SMD-LEDs 2 are mounted in the correct position relative to the reference points 3 of the circuit carrier 1, on the circuit carrier 1, in regard to their light-emitting regions 4. This circuit carrier 1 meets the requirements in regard to positioning accuracy of the light-emitting regions 4.

(12) FIGS. 4a, 4b and 4c show a process according to the invention including the steps: ascertaining the deviation in relation to the target position in the X-direction and the Y-direction of the reference point 3 i for all reference points 3 i (FIG. 4a), ascertaining the deviation in relation to the target position in the X,Y-direction and an angular position of the light-emitting region 4 of the SMD-LED 2 to be removed and in the Z-direction of the SMD-LED 2 to be removed (FIG. 4b), and mounting of the SMD-LED 2 to the circuit carrier 1 in the correct position relative to the reference points 3 i of the circuit carrier 1 (FIG. 4c).