JPH0743112A - Light emitting point detecting method and positioning device for luminous element - Google Patents

Abstract

PURPOSE:To precisely and simply detect the position and direction of the light emitting point of a luminous element with directivity such as a semiconductor laser beam. CONSTITUTION:Light from a semiconductor laser chip l is received with a lens 30 and the image thereof is projected on a CCD image pick-up element 31. This element 31 is positioned off the image point B of the chip 1 and as a result, what is called out-of-focus image is projected on the element 31. In this case, scattered light incident on the lens 30 is projected as a spread circular image, but the beam thereof is projected as one point, even if positioned off the image point B, because the light is not spread. Also, the required computation is undertaken, on the basis of a positional relationship among three of the optical axis of the lens 30, the center of the circular image and the beam image, thereby enabling the deviation (d) and inclination gamma of the chip l from the optical axis to be obtained through a calculation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting point detecting method and a positioning device for accurately attaching a light emitting element such as a semiconductor laser chip to a mounting position such as a stem.

[0002]

2. Description of the Related Art Since a semiconductor laser is used in an extremely high-accuracy device such as a CD player, it is necessary to determine the light-emitting point position with high accuracy when the chip is attached to the main body.
For this reason, conventionally, the shape of the divided chips is image-recognized by a CCD camera or the like, and the carrying posture is corrected based on the image recognition for die bonding.

A device for the above positioning is shown in FIG.
This device has an intermediate station 103 for positioning and correction. The divided semiconductor laser chip 100 is conveyed to the intermediate station 103. The semiconductor laser chip 100 is transported from the tray 101 by the first suction nozzle 102. A CCD camera 104 is provided above the intermediate station 103, and its position is recognized based on the outer shape and electrode pattern of the semiconductor laser chip 100 set on the intermediate station 103. If the position is deviated, the position correction tab 105 provided around the intermediate station 103 is used.
Correct the position of. After correction, the second suction nozzle 10
The semiconductor laser chip 100 is adsorbed by using 6 and conveyed to the die bonder.

[0004]

However, the positioning device shown in FIG. 8 has the following drawbacks.

First, the positioning is performed based on the external shape and electrode position of the semiconductor chip. However, the light emitting point of the semiconductor laser chip is not always located at the same position with respect to its outer shape, and there are variations within a certain range. However, if the positioning is performed based on the outer shape of the chip, this variation cannot be compensated.

The semiconductor laser chip is set in the intermediate station, its position is corrected, and the semiconductor laser chip is again sucked by the suction nozzle and conveyed to the die bond device. However, when the semiconductor laser chip is sucked by the second suction nozzle, a slight positional deviation occurs. In some cases, the positioning accuracy was not improved.

It is an object of the present invention to provide a light emitting element detecting method and a positioning device for a light emitting element, which can eliminate the variation of the light emitting points in the light emitting element and can prevent the positional deviation during transportation.

[0008]

A light emitting point detecting method according to claim 1 of the present application is characterized in that a light emitting element having directivity is caused to emit light,
This light is received by a lens, projected on a light receiving surface provided at a position deviated from the image point, and based on the projected image of the light emitting element, from the optical axis of the lens of the light emitting point of the light emitting element. It is characterized by detecting the deviation and the inclination.

A positioning device according to a second aspect of the present application has a carrying mechanism for adsorbing the divided light emitting element chips and carrying them to a mounting position, and causing the light emitting element chips to emit light during the carrying and receives the light. A light emitting point detecting means for detecting the position and the direction of the light emitting point of the light emitting element chip, and a correcting means for correcting the carrying posture of the light emitting element chip based on the detection result of the light emitting point detecting means. It is characterized by that.

According to a third aspect of the present application, in the invention of the second aspect, the light emitting point detecting means detects the position and the direction of the light emitting point a plurality of times and the average value thereof is used as the detection result. Is characterized by.

According to a fourth aspect of the present invention, in the positioning device according to the second and third aspects, the correcting means and the light emitting point detecting means are provided until the detection result of the light emitting point detecting means reaches a value within a certain range. Is repeatedly executed.

[0012]

A light emitting element having directivity such as a semiconductor laser emits strong light (beam light) that does not spread and weak light (diffused light) that spreads. When these lights are received by the lens, the beam light does not spread and is projected as a point even if received at a position deviating from the image point, but the diffused light is focused by the lens at the image point and the beam light is Is projected as a point that coincides with, but at a position outside the image point,
It does not converge and is projected on the lens shape (circular shape). At a position deviated from the image point, the relationship between the optical axis of the lens and the center position of the projected image of this diffused light and the projected position of the beam light is as follows. Direction) corresponds to the inclination from the optical axis. Therefore, by measuring the distance between the optical axis of the lens, the center position of the projected image, and the projected position of the beam light, and performing a predetermined calculation based on the distance of the light emitting element-lens-light receiving surface, the light of the lens at the light emitting point is measured. It is possible to detect the deviation from the axis and the inclination.

According to a second aspect of the present invention, there is provided light emitting point detecting means for detecting the position and direction of the light emitting point of the light emitting element based on the deviation and the inclination from the optical axis of the lens by the above method. This operation is performed during the transportation of the transportation mechanism that sucks the light emitting element chips and transports them to the mounting position. Further, the attitude of the light emitting element chip conveyed is corrected based on the detection result. As a result, the transport element chip transported to the mounting position is accurately positioned, and the mounting accuracy of die bonding or the like can be increased. In this case, since the positioning is determined based on the position of the light emitting point itself, the deviation between the outer shape and the light emitting point does not affect the positioning accuracy. Furthermore, since the transport mechanism does not re-suck the light-emitting element chip after correcting the position of the light-emitting element chip, there is no room for displacement of the suction value.

According to the third aspect of the invention, the detection variation can be eliminated by performing the light emitting point detection means a plurality of times.

Further, in the invention of claim 4, the correcting means and the light emitting point detecting means are repeatedly executed until the detection result of the light emitting point detecting means reaches a value within a certain range, whereby the positioning accuracy can be further enhanced. . In this case,
By correcting the posture, noise and the like can be canceled and the detection accuracy can be improved.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a semiconductor laser carrying device to which an embodiment of the present invention is applied. The semiconductor laser carrying device is incorporated in a semiconductor laser device manufacturing apparatus, and is a device for carrying the semiconductor laser chip 1 from the tray 10 to a die bonding device (not shown).
During the transportation (position shown in the figure), the transportation attitude is corrected to make the light emitting point constant during die bonding.

In FIG. 1, a plurality of divided semiconductor laser chips 1 are arranged and mounted on a tray 10. The suction nozzle 2 sucks one of them and conveys it to the die bonder. A conductor laser positioning device as shown in the figure is installed in the middle of the transport path. When the suction nozzle 2 sucks the semiconductor laser chip 1 and reaches the position of this positioning device, it temporarily stops. A movable electrode terminal 4 is provided below the stopped suction nozzle 2, and the movable electrode terminal 4 moves upward to move the semiconductor laser chip 1.
To contact. On the other hand, the suction nozzle 2 also serves as the other electrode terminal, and a current is supplied from the controller 5 to the semiconductor laser chip 1 via the suction nozzle 2 and the movable electrode terminal 4. As a result, the semiconductor laser chip 1 emits light. In addition, C facing the light emitting portion of the semiconductor laser chip 1
A CD camera 3 is provided. The CCD camera 3 receives the light of the semiconductor laser chip 1 and inputs the image to the control unit 5. The control unit 5 detects the position and orientation of the semiconductor laser chip 1 based on the image of the CCD camera 3, and controls the suction nozzle 2 based on the data to correct the posture. The distance between the light emitting point of the semiconductor laser chip 1 and the lens of the CCD camera 3 is a.

Here, the CCD camera 3 is provided with a lens 30 (see FIG. 2), a lens barrel and a CCD image pickup device 31, but the CCD image pickup device is a light emitting point of the semiconductor laser chip 1 (hereinafter, simply in this description). "Semiconductor laser chip 1") is provided at a position deviated from the image point. Semiconductor laser chip 1 projected on CCD image sensor
2 to 5 show images of the light emitting points of.

As described above, the semiconductor laser chip 1 stops at the position of the distance a with respect to the lens 30. Lens 30
Has a focal length of f. The image point of the semiconductor laser chip 1 is the distance b from the lens 30. Furthermore, CCD
The image sensor 31 is provided at a distance L from the lens 30. This L is represented by L = b + c. That is, CC
The D image pickup device 31 is provided so as to be separated from the image point by c. Therefore, the image projected on the CCD image pickup device 31 is in a so-called out-of-focus state. As mentioned above,
A light emitting element having directivity such as the semiconductor laser chip 1 emits a beam of light and a diffused light, but since the beam of light is light that does not spread, even if the CCD image pickup device 31 is provided outside the image point, The image appears as a dot. on the other hand,
The diffused light enters the entire aperture of the lens 30 and is focused on the image point B. However, since the CCD image pickup device 31 is provided off the image point B, the image has the same circular shape as the aperture of the lens. Become.

In FIG. 2, the semiconductor laser chip 1 has a lens 3
It shows a state in which the orientation is set on the optical axis of 0 so as to match the optical axis of the lens 30. In this state, the optical axis of the lens 30 and the center of the image of the light beam projected on the CCD image pickup device 31 and the center of the circular image (circular image) formed by the diffused light coincide with each other. In the figure, a long ellipse drawn at the center of the circular image shows the image of the light beam emitted from the light emitting point of the semiconductor laser chip 1. Since the semiconductor laser chip has a wide active layer, the beam light is horizontally long.

In FIG. 3, the semiconductor laser chip 1 has a lens 3
It is placed on the optical axis of 0, and the direction is inclined by θ from the optical axis. Even in this state, the diffused light enters as in the case of FIG. 2, so the circular image projected on the CCD image pickup device 31 is shown in FIG.
Is the same as. However, since the light beam is obliquely incident, it passes through the image point B and is projected at a position separated by r from the center of the circular image. This r is determined by the inclination θ of the light beam and the distance a between the semiconductor laser chip 1 and the lens 30.
That is, the deviation e of the light beam from the optical axis in the lens 30 is represented by e = a tan θ, and the relationship between e and r is e / b = r / c. Therefore, if r is obtained, then e = r · b / c and tan θ = (r · b) / (c · a). Therefore, the inclination θ of the semiconductor laser chip 1 is obtained by θ = tan ⁻¹ ((r · b) / (c · a)). If the direction of the semiconductor laser chip 1 is rotationally corrected by this θ, the semiconductor laser chip will be in the correct posture.

Here, the suction nozzle 2 not only operates in the direction in which the semiconductor laser chip is conveyed from the tray 10 to the die bonding apparatus, but also can move with high accuracy in the vertical direction and the rotation direction thereof ( (See FIG. 1). The control of the attitude of the suction nozzle 2 is performed by the controller 5.

FIG. 4 shows a semiconductor laser chip 1 (beam light).
The direction of is parallel to the optical axis of the lens 30, but shows the projection image when the position of the semiconductor laser chip 1 is displaced by b from the optical axis. In this case, the circular image projected on the CCD image pickup device 31 is shifted by s from the optical axis. This s is s = (L / a) d: L = b + c, and therefore d is calculated by d = (a / L) s. In this case, the semiconductor laser chip 1 can be moved to the correct position by shifting it by d.

Further, even in this case, since the beam light does not enter the center of the lens 30, it is projected at a position further displaced from the optical axis than the center of the circular image. The deviation t between the center of the circular image and the image of the light beam is expressed by t = (c / b) d, and by substituting the above equation, t = (c / b) (a / L) s. Becomes That is, d is obtained by s, and this d and t
If the relationship is expressed by the equation, it is understood that the direction of the semiconductor laser chip 1 is parallel to the optical axis.

In FIG. 5, the semiconductor laser chip 1 has a lens 30.
2 is a projection view in the case where it is set off the optical axis and the direction is also tilted from the optical axis. The deviation of the semiconductor laser chip 1 is d and the inclination is θ. In this case, by using the same calculation (expression) as in FIG. 4, d based on the deviation s from the optical axis of the center of the circular image
Can be asked. Although t is obtained by using an equation based on d thus obtained, this t and the center of the circular image in this figure and the deviation u of the image of the light beam do not match. This is because u = r + t. Therefore, the value obtained by subtracting t from u is the deviation r due to the inclination θ of the semiconductor laser chip 1. The inclination θ can be obtained by using an equation based on this value r.

D and θ obtained by the above calculation
By only correcting the position, the position of the light emitting point of the semiconductor laser chip 1 conveyed to the die bonding apparatus can be always made the same.

Thus, in this CCD camera 3, CC
By providing the D image pickup device 31 at a position deviated from the image point B of the semiconductor laser chip 1, the image of the beam light and the circular image of the diffused light can be separately projected, and the chip based on the positional relationship between them. It is possible to detect the position and orientation of the at the same time.

In the above description of FIGS. 2 to 5, it is assumed that the distance a between the semiconductor laser chip 1 and the lens 30 is always constant. Based on this, a can be calculated and the above calculation can be performed. That is, when a changes, the position of the image point B changes, so the ratio of b and c changes. If the ratio of b and c changes, the size of the circular image φ2
(See FIG. 2) changes in size. Since φ2 has a relationship of φ2 = (c / b) φ1 with the aperture φ1 of the lens 30,
Based on this, a can be calculated.

FIG. 6 is a flow chart showing the operation of the control section 5. First, the suction nozzle 2 is driven to drive the tray 1.
Pick up one semiconductor laser chip from 0,
The CD is conveyed to the position of the CD camera 3 (first half conveyance: n
1). Next, the position and orientation of the semiconductor laser chip 1 are detected by the method described in FIGS. This position and orientation are detected as a shift and a tilt with respect to the optical axis of the lens 30 of the CCD camera 3. This is repeated N times. The reason for repeating is to cancel the variation at the time of detection. A detection result is obtained by averaging the detection values of N times. If it is determined from this detection result that the posture is correct, that is, if the position and orientation of the semiconductor laser chip 1 match the optical axis of the lens 30, the second half conveyance (conveyance to the die bonding apparatus) is performed (as it is). n4). On the other hand, when the detection result does not match the optical axis, the posture is corrected (n6), and the detection work of n2 is performed again. If the position cannot be corrected correctly even after performing this M times, the device is either faulty or the semiconductor laser chip is defective, so the device is temporarily stopped (n
5).

By repeating the detection operation N times as described above and calculating the average, it is possible to cancel the variation in each time and obtain an accurate detection result. further,
When the detection result deviates from the optical axis, the posture is corrected and the detection is performed again, whereby the posture can be corrected with high accuracy. Further, since the position and the direction of shooting are changed by this correction, the shooting position is closer to the optical axis, so that the shooting error due to noise is canceled and the detection accuracy can be further improved.

Further, in the CCD camera 3 of the above embodiment,
Although the CCD image pickup device 31 is installed farther from the lens 30 than the image point B, the same effect can be obtained by installing the CCD image pickup device 31 closer to the lens 30 than the image point 31. FIG. 7 shows the light propagation state of the CCD camera configured as described above. In this case, the direction in which the image shifts when the incident point of the light beam is shifted is opposite to that in the case of FIGS.

[0032]

As described above, according to the present invention, a light emitting element such as a semiconductor laser having directivity is received by a lens and projected on a light receiving surface at a position deviating from the image point, Since the image at the center of directivity and the image of the diffused light that has entered the entire aperture of the lens are projected in a distinguishable manner, the position and orientation of the light-emitting element can be determined according to the positional relationship between these and the optical axis of the lens. It can be detected at the same time. As a result, it is possible to accurately perform the positional accuracy based on the light emitting point of the light emitting element in one step.

Further, in the case of detecting the position and direction of the light emitting point of the light emitting element chip by using the above method, it is carried out during the transportation of the light emitting element chip from the tray or the like to the mounting position. Therefore, it is possible to save the labor of setting the light emitting element chip, and to eliminate the possibility of the displacement of the position at the time of adsorption. Further, by detecting the position and orientation of the light emitting point a plurality of times and calculating the average value thereof, it is possible to cancel the variation in the detected value at each time. Furthermore, the correction of the posture of the light emitting element chip and the detection of the position and the direction of the light emitting point are repeatedly executed by the correction means, whereby the position can be corrected with higher accuracy.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a semiconductor laser carrying device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a state of light entering a CCD camera 3 of the semiconductor laser carrying device.

FIG. 3 is a diagram showing a state of light entering a CCD camera 3 of the semiconductor laser transport device.

FIG. 4 is a diagram showing a state of light entering a CCD camera 3 of the semiconductor laser transport device.

FIG. 5 is a diagram showing a state of light entering a CCD camera 3 of the semiconductor laser transport device.

FIG. 6 is a flowchart showing an operation of a control unit of the semiconductor laser carrying device.

FIG. 7 is a view showing another embodiment of the CCD camera 3 used in the semiconductor laser carrying device.

FIG. 8 is a diagram showing a configuration of a conventional semiconductor laser positioning device.

[Explanation of symbols]

 1-Semiconductor laser chip 2-Suction nozzle 3-CCD camera 4-Movable electrode terminal 30-Lens 31-CCD image sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumio Torimatsu 22-22 Nagaike-cho, Abeno-ku, Osaka, Osaka

Claims (4)

[Claims] 1. A light emitting element having directivity is caused to emit light, this light is received by a lens, and projected on a light receiving surface provided at a position deviating from the image point, and an image of the projected light emitting element is obtained. A method for detecting a light emitting point of a light emitting element, characterized in that the deviation and the inclination of the light emitting point of the light emitting element from the optical axis of the lens are detected based on the light emitting point. 2. A transport mechanism for adsorbing the divided light-emitting element chips to a mounting position, and causing the light-emitting element chips to emit light during the transportation and receiving the light to emit light from the light-emitting element chips. Of the light emitting element, which is provided with a light emitting point detecting means for detecting the position and direction of the light emitting element, and a correcting means for correcting the carrying attitude of the light emitting element chip based on the detection result of the light emitting point detecting means. Positioning device. 3. The light emitting element positioning device according to claim 2, wherein said light emitting point detecting means detects the position and direction of said light emitting point a plurality of times and uses the average value as the detection result. 4. The light emitting element positioning device according to claim 2, wherein the correcting means and the light emitting point detecting means are repeatedly executed until the detection result of the light emitting point detecting means reaches a value within a certain range. .