JPH10307251A - Focus detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive focus detector where an inexpensive clear mold package type image sensor is used and a low viscosity adhesive is used to stick the image sensor to a holding member. SOLUTION: This detector is provided with bank parts 93a and 93b protruded from adhesive areas 91a and 91b between a luminous flux passing area and the areas 91a and 91b on the clear mold package type image sensor 90. Thus, the adhesive is prevented from flowing into the luminous flux passing area when the sensor 90 is stuck to an optical system unit 10. Or the detector is provided with a mask for preventing harmful stray light from entering a sensor chip 96, and the mask is also used to perform a function for preventing the adhesive from flowing into the luminous flux passing area on the clear mold package type image sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus detection device such as a camera.

[0002]

2. Description of the Related Art Conventionally, there are various types of focus detecting devices which detect a light flux from a subject by an image sensor to detect a focus adjustment state of the photographing lens with respect to the subject, and most of them include an image sensor and a holding member for holding the image sensor. It is fixed by bonding. This is because the focus detection device is suitable for reducing the size and cost, and for fixing the holding member and the image sensor after adjusting their positions.

[0003] Above all, the cost can be further reduced by using a clear mold package type image sensor. In this case, the surface on the light receiving part side of the image sensor needs to be a mirror surface for optical reasons. Therefore, considering manufacturing a mold for making the image sensor, the surface on the light receiving part side of the image sensor is concave. It is preferable to polish the top of the convex part of the mold corresponding to the above. And
The periphery of the concave portion of the image sensor is adhesively fixed to the holding member.

The adhesive used for bonding and fixing the image sensor of the clear mold package type and the holding member is a low-viscosity adhesive such as a cyanoacrylate-based instant adhesive which improves the efficiency of the bonding work because of its quick curing time. Is preferred. However, if bonding is performed using a low-viscosity adhesive, if the surface on the light receiving section side of the clear mold package type image sensor is concave, the low-viscosity adhesive flows into the concave portion and blocks the light beam used for focus detection. Alternatively, the luminous flux may be disturbed by the catadioptric action of the adhesive, which may adversely affect focus detection. Therefore, a low-viscosity adhesive cannot be used in practice. That is, the adhesive that can be used is limited due to various factors such as work convenience and adhesive strength.

Here, in order to prevent the adhesive from flowing into the surface on the light receiving portion side, the surface on the light receiving portion side of the image sensor is formed in a convex shape, and the bottom of the corresponding concave portion of the mold is polished. It is also possible. Also, JP-A-7-318
No. 790 discloses that the surface on the light receiving portion side of the image sensor is made convex, the surfaces are polished one by one, and the peripheral portion is bonded and fixed to a holding member.

On the other hand, in Japanese Patent Application Laid-Open No. 6-88931, a glass plate is adhered to the surface on the light receiving portion side of the image sensor.
It is disclosed that an adhesive is fixed to a holding member at a peripheral portion so that the adhesive does not flow into the surface on the light receiving section side.

[0007]

If the surface on the light receiving portion side of the image sensor is made convex, there is no fear that the low-viscosity adhesive flows into the surface. However, in order to make a region through which a light beam passes on the surface on the light receiving portion side of the image sensor convex, a corresponding portion of a mold for producing the region must be concave. Therefore, it is necessary to polish the bottom of the concave portion corresponding to the mirror surface in manufacturing the mold, which is difficult in operation. Further, in the invention disclosed in Japanese Patent Application Laid-Open No. 7-318790, it is considered that the above-mentioned difficulties in manufacturing the molds can be avoided, but the cost is increased by each polishing process.

On the other hand, according to the invention disclosed in Japanese Patent Application Laid-Open No. 6-88931, there is no danger of the adhesive flowing in by bonding a glass plate to the surface of the image sensor on the light receiving portion side. However, it is costly to add a glass plate only to prevent the adhesive from flowing. The present invention solves these problems, and provides an inexpensive focus detection device that can use an inexpensive clear mold package type image sensor and use a low-viscosity adhesive to bond it to a holding member. With the goal.

[0009]

FIG. 1 shows an embodiment of the present invention.
6 will be described in association with FIG. According to the first aspect of the present invention, in the focus detection device including the image sensor 90 having the sensor chip 96 and the optical system unit 10 for guiding the light beam to the light receiving unit of the sensor chip 96, the image sensor 90 is provided with the light receiving unit of the image sensor 90. Adhesion areas 91a, 9 for adhering the optical system unit 10, which are provided on at least a part of the side surface outside the light beam passage area.
1b, and step regions 93a and 93b provided between the bonding regions 91a and 91b and the light beam passage region.

According to the second aspect of the present invention, the adhesive regions 91a, 91
1b and a predetermined interval between the step regions 93a and 93b. According to the third aspect of the present invention, in the focus detection device including the image sensor 290 having the sensor chip 96 and the optical system unit 10 for guiding the light beam to the light receiving portion of the sensor chip 96, a part of the area on the image sensor 290 is covered. The image sensor 290 includes a mask 280, and is provided with bonding regions 91a and 91b for bonding the optical system unit 10, which are provided on at least a part of the surface on the light receiving unit side of the image sensor 290 outside the light beam passing region. And the end 28 of the mask 280
1a and 281b are brought into contact between the adhesive regions 91a and 91b and the light beam passage region.

According to a fourth aspect of the present invention, the image sensor 9
0 is a clear mold package type.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 is an exploded perspective view of the focus detection device according to the first embodiment. FIG. 2 is an XZ plane showing a clear mold package type image sensor 90 in a state where the focus detection device shown in FIG. 1 is assembled. It is sectional drawing which cut | disconnected. The holding member 50 incorporates optical elements such as a lens, a mirror 120, and a field mask 70 therein. Here, these are referred to as an optical system unit 10 as a whole. The clear mold package type image sensor 90 detects a light quantity distribution due to a light beam incident through the photographing lens of the camera (not shown) and the optical system unit 10 and performs an arithmetic processing on the output by a CPU (not shown) to perform photographing. Detect the focus adjustment state of the lens.

FIG. 1 shows an optical system unit 10 for convenience of explanation.
And clear mold package type image sensor 90
Are drawn apart from each other, but in reality both are bonded and fixed. First, the relative position in the XY plane in FIG. 1 is adjusted while pressing the clear mold package type image sensor 90 against the holding member 50 on the adjusting device, and then the adhesive is applied on the adjusting device as it is. Done.

At this time, a cyanoacrylate-based instant adhesive is used. The adhesive is dropped onto portions indicated by arrows B1 and B2 in FIG. 2 so that the adhesive is attached to the holding member 50 and the clear mold package type image sensor. 90, that is, 5
It penetrates and solidifies between 1a and 91a and between 51b and 91b by capillary action. The focus detection device must be removed from the adjustment device after the adhesive has hardened to a considerable extent, but since the instant adhesive hardens quickly, it can be removed quickly and efficiently. However, since the adhesive has a low viscosity, a part of the adhesive may protrude from the contact portion when dropped, and may further flow in the direction of the light-passing area of the clear mold package type image sensor 90. Here, without the levee portions 93a and 93b, the protruding adhesive may flow into the mirror-shaped concave portion 94 and disturb the light flux incident on the sensor chip 96 therefrom.

However, the dikes 93a and 93b prevent the adhesive from flowing in the direction of the light beam passing area of the clear mold package type image sensor 90.
Therefore, the light beam incident on the sensor chip 96 is not disturbed, and the accuracy of focus detection is not disturbed.
Further, since an inexpensive clear mold package type image sensor can be used and a low-viscosity adhesive can be used for adhesion between the image sensor and the holding member 50, an assembling workability is good, and an overall inexpensive focus detection device is obtained. be able to. Further, the embankments 93a, 93b and the bonding areas 91a,
By providing gaps 95a and 95b between the image sensor 9b and the image sensor 9 of a clear mold package type,
Since the adhesive that has protruded from the contact portion when the 0 is adhered to the holding member 50 can be stored in the gaps 95a and 95b, the adhesive flows into the light beam passage area beyond the embankments 93a and 93b. Disappears. Here, the embankments 93a and 93b are integrally formed on the surface of the image sensor 90 in the form of a clear mold package.

In the first embodiment of the present invention, the surface on the light receiving portion side of the image sensor of the clear mold package type is left concave, so that the surface of the clear mold package type image sensor is more convex than the convex surface. It is easy to produce molds required for manufacturing image sensors. That is, as shown in FIG. 3, the convex portion 98 of the mold 901 is polished to a mirror surface,
Since it is sufficient to form the groove 99 around the periphery, there is no need to polish the bottom of the concave portion, and there is no difficulty in manufacturing the mold.

A second embodiment of the present invention will be described with reference to FIGS. What is common to FIGS. 1 and 2 is
The same reference numerals are given and the description is omitted. FIG. 4 is an exploded perspective view of a focus detection device according to a second embodiment of the present invention. FIG. 5 shows a clear mold package type image sensor 190 in an assembled state of the focus detection device shown in FIG. It is sectional drawing cut | disconnected by the XZ plane. In the above-described first embodiment, the embankments 93a and 93b are around the mirror-shaped concave portion 94. In the second embodiment, however, a relatively peripheral portion in the mirror-shaped concave portion 194 is used. There are embankments 193a and 193b. This embankment part 193
With a and 193b, the same effect as in the first embodiment can be obtained.

In the first and second embodiments, the dikes 93a, 93b are provided to prevent the adhesive from flowing.
b, 193a, 193b, but the embankment 93a, 9
A configuration in which a groove is provided instead of 3b, 193a, and 193b may be adopted. In this case, when the clear mold package type image sensor is adhered to the holding member 50, the adhesive that protrudes from the contact portion flows into the groove, so that the adhesive flows into the light flux passage area of the clear mold package type image sensor. Disappears. However, if an attempt is made to form a clear mold package type image sensor only by resin molding, unlike the first and second embodiments, it becomes difficult to polish a mirror surface near the center of the mold. Therefore, the grooves may be formed by first forming a shape having no grooves, and then machining the individual packages later. Even in such a case, the aforementioned Japanese Patent Laid-Open No. 7-31
The cost is lower than in the case of the 8790 prior art. This is because the mirror surface must be formed by post-processing in the above-described conventional technology, whereas the surface roughness of the groove may be rough and the dimensional accuracy is not so required in the present invention. In addition, since it is not necessary to provide the gaps 95a and 95b by providing the groove, it is possible to narrow a portion of the surface on the light receiving portion side of the clear mold package type image sensor that is outside the light beam passage region. That is, the size of the clear mold package type image sensor can be reduced.

A third embodiment of the present invention will be described with reference to FIGS. What is common to FIGS. 1 and 2 is
The same reference numerals are given and the description is omitted. FIG. 6 is an exploded perspective view of a focus detection device according to a third embodiment of the present invention. FIG. 7 shows a clear mold package type image sensor 290 in an assembled state of the focus detection device shown in FIG. It is sectional drawing cut | disconnected by the XZ plane. A mask 280 disposed immediately before a clear mold package type image sensor 290 having no dike or groove.
Is a light-shielding plate having an opening in the center thereof for transmitting an effective light beam used for focus detection. Mask 280
The ends 281a and 281b at both ends of the image sensor 290 are bent as shown in FIG. 6, and the ends of the ends 281a and 281b are adhered to the surface of the clear mold package type image sensor 290. Thereby, the mask 280 is attached to the holding member 5.
0 and clear mold package type image sensor 2
When adhering to the image sensor 90, the adhesive sticks out of the contact portion, and serves to prevent the adhesive from flowing into the light flux passage area of the image sensor 290 of the clear mold package type. The mask 280 also prevents harmful stray light from being incident on the sensor chip 96, and also has a role of not disturbing the accuracy of focus detection.

As described above, the use of the mask 280 prevents the adhesive from flowing into the light beam passage area of the image sensor 290 of the clear mold package type. Therefore, while using an inexpensive clear mold package type image sensor, the
Since a low-viscosity adhesive can be used for bonding to the substrate, assembly workability is also good. In addition, since harmful stray light can be prevented from being incident on the sensor chip 96, the accuracy of focus detection is not disturbed.

According to the third embodiment, the embankments 93a, 93a as in the first and second embodiments described above.
b, 193a, 193b or grooves are not required,
The mold required for manufacturing the clear mold package type image sensor is easier to manufacture, and the part of the surface on the light receiving part side of the clear mold package type image sensor that is outside the light passage area is further narrowed. Can be. Therefore, even if the light receiving portion of the light beam has the same size, the clear mold package type image sensor can be made smaller in the third embodiment than in the first and second embodiments.

According to FIG. 7, the end portions 281a and 281b of the mask 280 are located on the surface of the mirror-shaped recess 294, but not on the surface of the mirror-shaped recess 294 but on the periphery of the bonding regions 91a and 91b. It may be. In the first to third embodiments, the image sensor is described as a clear mold package type, but an image sensor other than a clear mold package type may be used.

In the above embodiment of the present invention, the embankments 93a, 93b, 193a, 193b or the grooves constitute the step region, and the gaps 95a, 95b constitute the predetermined intervals.

[0024]

As described above, according to the first aspect of the present invention,
In the invention of the above, the step region is provided in the image sensor, so that the adhesive flows into the light passage area of the surface on the light receiving portion side of the image sensor when the image sensor and the optical system unit are bonded. Disappears.

According to the second aspect of the present invention, since a predetermined distance is provided between the bonding area and the step area, a place where the overflowing adhesive collects when the image sensor and the optical system unit are bonded is determined. As a result, the adhesive does not flow into the light passage area of the surface of the image sensor on the light receiving section side beyond the step area. According to the third aspect of the present invention, by using the mask, the adhesive can be prevented from flowing into the light passage area of the light receiving portion side surface of the image sensor, and the stray light can be prevented from being incident on the sensor chip. Therefore, the accuracy of focus detection is not disturbed.

According to the fourth aspect of the present invention, an inexpensive focus detection device can be provided by using an inexpensive clear mold package type image sensor.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a focus detection device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the image sensor in a state where the focus detection device shown in FIG. 1 is assembled and a portion near the image sensor cut along an XZ plane.

FIG. 3 is a cross-sectional view illustrating a mold for manufacturing the image sensor shown in FIG.

FIG. 4 is an exploded perspective view showing a focus detection device according to a second embodiment of the present invention.

5 is a cross-sectional view of the image sensor in a state where the focus detection device shown in FIG. 4 is assembled and a portion near the image sensor cut along an XZ plane.

FIG. 6 is an exploded perspective view showing a focus detection device according to a third embodiment of the present invention.

7 is a cross-sectional view of the image sensor in a state where the focus detection device shown in FIG. 6 is assembled and a portion near the image sensor cut along an XZ plane.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Optical system unit 50 Holding member 51a, 51b Contact surface with image sensor 70 View mask 90, 190, 290 Image sensor 91a, 91b Contact surface with holding member 93a, 93b, 193a, 193b Embankment 94, 194, 294 Recess 95a, 95b gap 96 sensor chip 120 mirror 280 mask 281a, 281b end

Claims (4)

[Claims] 1. A focus detection device comprising: an image sensor having a sensor chip; and an optical system unit for guiding a light beam to a light receiving portion of the sensor chip, wherein the image sensor has a surface on a light receiving portion side of the image sensor. A bonding area for bonding the optical system unit, which is provided on at least a part of the outside of the light beam passing area, and a stepped area provided between the bonding area and the light beam passing area. A focus detection device. 2. The focus detection device according to claim 1, wherein the image sensor has a predetermined distance between the adhesive region and the step region. 3. A focus detection device comprising: an image sensor having a sensor chip; and an optical system unit for guiding a light beam to a light receiving portion of the sensor chip, comprising: a mask covering a partial area on the image sensor; The image sensor has a bonding area for bonding the optical system unit, which is provided on at least a part of a surface on a light receiving unit side of the image sensor outside the light beam passage area, and has an end of the mask. A focus unit that abuts a portion between the bonding area and the light flux passage area. 4. The focus detection device according to claim 1, wherein the image sensor is a clear mold package type.