JP2002365045A - Range finding sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a range finding sensor having a smaller size and a high accuracy as a constitution in which an IC package of a sensor for an auto- focusing camera is reexamined, reduced in size and weight and influenced by an environmental change. SOLUTION: In this range finding sensor, an image of an object focused through two photodetecting lenses 31a and 31b is detected on photodetecting surfaces 25a and 25b on an IC chip 25. The chip 25 is sealed together with leadless conductive parts 26a and 26b, electrodes 26c and 26d by glass members 27a and 27b. A flexible substrate 28 electrically connected to the electrodes 26c and 26d is disposed on the member 27b. An opening 28a is formed on the substrate 28 so that light beams from the lenses 31a and 31b can be guided on the photodetecting surface of the chip 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring sensor, and more particularly, to an improvement in an image sensor for an autofocus camera.

[0002]

2. Description of the Related Art Autofocus systems for cameras can be classified into an active system that receives light projected from the camera side to perform focus control, and a passive system that uses an image signal of a subject. Among them, the improvement regarding the configuration of the sensor for detecting the image signal for the passive system is as follows.
For example, Japanese Patent No. 3018846 is known.

[0003]

In recent years, as cameras have become smaller and lighter, focus control sensors have also been made smaller and lighter, and optical systems, ICs, and packages have been reviewed. .

However, the aforementioned Japanese Patent No. 3018846
In the configuration based on a flat package with leads, which was used in Japanese Patent Application Publication No. 2000-163, there was a limit to downsizing of the sensor.

The present invention has been made in view of the above situation, and has been reconsidered from the level of a package for enclosing and protecting the IC portion of the focus control sensor, enabling a reduction in size and weight, and a change in the environment in which the camera is used. Regardless of the above, an object of the present invention is to provide a distance measuring sensor capable of performing stable focusing.

[0006]

That is, the present invention provides a method of
A semiconductor chip having a light receiving surface for detecting an image of an object formed through two lenses, a transparent package with leadless electrodes for enclosing the semiconductor chip, and a package arranged on the transparent package A flexible substrate electrically connected to an electrode of the transparent package, wherein the flexible substrate has an opening formed on a light receiving surface of the semiconductor chip so that light from the lens can be guided. It is characterized by the following.

Further, the present invention provides a sensor chip having a light receiving surface and an electrode pad on the same surface, a transparent package enclosing the sensor chip except for at least the electrode pad, and a flexible package electrically connected to the electrode pad. A substrate and a transparent package that is bonded on the transparent package;
A lens holding member for guiding light from the image of the object formed through the two lenses to the light receiving surface.

In the distance measuring sensor according to the present invention, the image of the object formed through the two lenses is detected on the light receiving surface of the semiconductor chip, and the semiconductor chip is formed by a leadless transparent package with electrodes. Enclosed. Then, a flexible substrate that is electrically connected to the electrodes of the transparent package is disposed on the transparent package. here,
The flexible substrate has an opening formed on a light receiving surface of the semiconductor chip so that light from the lens can be guided.

In the distance measuring sensor according to the present invention, a light receiving surface and an electrode pad are arranged on the same surface of the sensor chip.
The sensor chip is sealed in a transparent package except for at least the electrode pads. A flexible substrate is electrically connected to the electrode pads. And
A lens holding member that guides light from the image of the object formed through the two lenses to the light receiving surface is bonded onto the transparent package.

The point when downsizing the distance measuring sensor is as follows.
In addition to simply reducing the configuration, consideration is given to obtaining a stable image detection characteristic without being affected by changes in temperature and humidity, changes over time, and the like. These are made possible by enclosing in the package and limiting the bonding points.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

First, a general distance measuring sensor will be described with reference to FIG.

In FIG. 2, a chip-like sensor IC 1 is shown.
Are mounted on a lead frame 3a mounted on the flexible substrate 2. One end of a wire 5 serving as a signal line is connected to a bonding pad on the sensor IC 1, and a lead frame 3 b different from the lead frame 3 a is connected to the other end of the wire 5. I have. The lead frame 3b is also attached to the flexible board 5 like the lead frame 3a. The leads 3a and 3b are connected to the flexible substrate 2
, Communication with a control circuit (not shown) is performed.

The sensor IC 1 and the lead frame 3a
And 3b, the wire 5 is protected by being covered with a transparent resin package 6. A holding member 8 to which a lens 7 for guiding an image signal to the sensor IC 1 is attached is adhered on the resin package 6.
The holding member 8 holds the lens 7.

[0015] In the distance measuring sensor of such a configuration, as shown in FIG. 2, from the edge of the lead frame to the edge it takes magnitude of Y _p. This is in fact than the size Y _c of the sensor IC1 have important functions not contained within the camera that there is no large space much.

FIG. 3 is a diagram for explaining the principle of distance measurement of a passive type distance measuring device for a camera.

Referring to FIG. 3, the AF camera is
A distance measuring sensor 12 for measuring a distance L to the camera, a CPU 14 as an arithmetic control unit for focusing the photographing lens 13 on the obtained distance L, and a driving unit for driving the photographing lens. It has a lens driver 15.

The distance measuring sensor 12 is divided into lenses 18a and 18b for receiving light from the subject 11 to detect an image signal of the subject 11 and an intensity distribution of the obtained light. Sensor arrays 19a and 19
needs b. The sensor IC 1 provided with these sensor arrays 19a and 19b is enclosed in a package 20 for protecting the sensor surface and preventing corrosion of chip electrodes and the like. The distance measuring sensor 12 is used to hold the lenses 18a and 18b.
I need one.

Here, the detection of the distance L is based on the relative image position difference x obtained by the two lenses 18a and 18b having the parallax B and the lens focal length f.
The relational expression of L = B · f / x is used. However,
This relational expression assumes that the positional relationship between the lens and the sensor array is constant. Therefore, if this relationship is disturbed by a change in the environment or a change with time, correct distance detection cannot be performed, and correct focusing cannot be performed.

Therefore, in the present invention, the structure is simplified as much as possible, and the bonding points are limited so as to be hardly affected by the temperature change of the adhesive. Further, by eliminating the lead frame and adopting a package having substantially the same size as the IC chip, a reduction in size and weight can be achieved.

As for a package having substantially the same size as an IC chip, a chip size package has been commercialized by ShellCASE of Israel.
If this technology is applied, the above-mentioned package can be easily commercialized.

FIG. 1 shows a first embodiment of the present invention, in which (a) is a sectional view showing the configuration of a distance measuring sensor.
FIG. 2B is an exploded view of the sensor unit of the distance measuring sensor.

A bonding pad is provided at an end on one surface of the IC chip 25 serving as a distance measuring IC.
Conductive portions 26a and 26b for exchanging electric signals are provided on the bonding pads. The IC chip 25 and the conductive portions 26a and 26b are sandwiched between glass members 27a and 27b.

Further, along the outer surface of the glass member 27b, there are formed electrode portions 26c and 26d, one ends of which are electrically connected to the conductive portions 26a and 26b, respectively.

The electrode portions 26c and 26d are further electrically connected to the flexible substrate 28. The flexible substrate 28 is provided with the CPU shown in FIG.
14 enables communication with the sensor IC.

Further, an opening 28a is formed in the flexible substrate 28. In this opening 28a,
A projection 30b formed at the end of the lens holding member 30 is fitted. Then, the lens holding member 30 and the glass member 27b are bonded to each other by an adhesive or the like applied to the bonding portion 30a provided on the end surface of the protrusion 30b. The lens holding member 30 has a light receiving lens 31 on its end face so as to be arranged at a predetermined distance from the IC chip 25.
(31a, 31b) are held.

As described above, the light receiving lenses 31a and 31a
The lens holding member 30 having the protrusion 1b is provided with the IC chip 25 by the glass members 27a and 27b through the opening 28a formed in the flexible substrate 28.
Is connected to the package 27 in which the components are sealed. On the surface of the package 27 facing the lens holding member 30, the light receiving lens 31a,
On-chip light receiving surfaces 25a and 25b are provided so that an optical signal from a subject through 31b is incident.

By configuring the distance measuring sensor in this manner, a much smaller and lighter focus controlling sensor configuration can be realized than the configuration of the distance measuring sensor as shown in FIG.

In addition, such a package applies a microfabrication technology such as glass deposition, etching, and dining at the IC wafer level, and is attracting attention in recent years of the technical improvement of image sensors. Is what it is.

FIG. 4 is a sectional view showing a configuration of a distance measuring sensor according to a second embodiment of the present invention.

In the above-described first embodiment, the projection 3b of the lens holding member 30 is inserted into the opening 28a of the flexible substrate 28, but in the second embodiment, the light-receiving lens holding No projection is provided on the lens holding member 32, and the glass member 27b 'on the conductive portions 26a and 26b is provided.
Through the opening 28a of the flexible substrate 28.

That is, the glass member 27b 'on the light receiving side constituting the package 27' is formed thicker than the glass member 27b shown in FIG. Further, the electrode section 26
The height direction of c 'and 26d' is reduced so that the surface of the glass member 27b 'is exposed from the opening 28a when connecting to the flexible substrate 28. Then, the lens holding member 32 is bonded to the exposed surface of the glass member 27b '.

Also in the second embodiment, the lens holding member 32 is bonded by the bonding portion 30a provided on the surface of the glass member 27b 'to limit the bonding points. Therefore, the effects of environmental changes can be eliminated by a simple structure that minimizes the effects of other members such as the flexible substrate 28.

Next, a third embodiment of the present invention will be described.

FIG. 5 is an exploded view showing the configuration of a distance measuring sensor according to the third embodiment.

In the first and second embodiments described above,
The projection 30b of the lens holding member 30 and the glass member 27b 'are fitted into the opening 28a of the flexible substrate 28, but in the third embodiment, the opening 28a is used only for guiding light to the sensor surface. It is configured to be used.

That is, the lens holding member 34 for holding the light receiving lenses 31a, 31b is provided with protrusions 34b, 34b at the sensor-side end. And these projections 34
The package 27 and the flexible board 28 in which the opening 28a is formed are sandwiched between b and 34b. In this case, the side portion 27 of the package 27
c, 27c are protrusions 34b, 34b of the lens holding portion 34
Are adhered to the adhesive surfaces 34a, 34a provided on the inner side surface.

As described above, the opening 28a of the flexible substrate 28 is used only for guiding light between the light receiving lenses 31a and 31b and the light receiving surfaces 25a and 25b on the chip. In such a distance measuring sensor, an optical signal other than the image from the light receiving lens
If it is incident on C, accurate distance measurement cannot be performed.

Therefore, after the members shown in FIG. 5 are assembled as shown in FIG.
As shown in (2), the flexible substrate 28 is bent forward (toward the lens). Then, from behind (on the sensor side), a light-shielding light member 35 is attached so as to cover the package 27 from above and below in FIG. An excellent and compact distance measuring sensor can be configured.
Note that the left and right direction of the package 27 is the lens holding member 34.
Are shielded by the projections 34b, 34b.

As described above, according to the third embodiment, it is possible to provide a distance measuring sensor which is excellent in light-shielding properties and which is small and lightweight.

In the above-described first to third embodiments, the lens holding member is directly bonded on the package in order to minimize the influence of the temperature and humidity changes of the adhesive or the like. It is not limited.

In the fourth embodiment described below, a glass sealing portion is used to protect the sensor surface and prevent the adhesive from adversely affecting the IC chip, and the flexible substrate is directly mounted on the flip chip. This is an example of connecting by a method.

In FIG. 7A, a glass protective film 41 is formed only on the light receiving surfaces 25a and 25b on the IC chip 40 and on the portion where the lens holding member 38 is bonded by vapor deposition or the like. In addition, the bonding electrode portions 40a and 40b are not sealed, but are exposed on the IC chip, and are electrically connected to the flexible substrate 39 by solder bumps or the like.

The flexible substrate 39 has a notch 39
The glass protective film 41 is inserted into the notch 39a. This allows
Light from the light receiving lenses 31a and 31b is guided to the light receiving surfaces 25a and 25b without being interrupted.

FIG. 7B is a view showing a state where the distance measuring sensor having such a configuration is assembled.

The lens holding member 38 is formed on the glass protective film 41.
Are bonded, and the electrode portions 40b (40
FIG. 7A shows that the flexible substrate 39 is electrically connected.

As described above, according to the fourth embodiment, the mold made directly on the glass sealing portion on the chip,
Since the lens holding member is bonded, it is possible to reduce the influence of the adhesive and to prevent the adverse effects on the chip surface due to components such as moisture contained in the adhesive, thereby forming a small and lightweight distance measuring sensor. it can.

According to the above embodiment of the present invention,
The following configuration can be obtained. (1) A semiconductor chip having a light receiving surface for detecting an image of an object formed through two lenses, a transparent package with leadless electrodes for enclosing the semiconductor chip, In a distance measuring sensor having a flexible substrate electrically connected to an electrode, the flexible substrate has an opening, and light from the lens can be guided to a light receiving surface of the semiconductor chip. A distance measuring sensor characterized by the above-mentioned.

(2) The method according to (1), wherein the holding member has a projection having a thickness greater than the thickness of the flexible substrate for directly bonding the package and the holding member for holding the two lenses. The distance measuring sensor as described.

(3) A sensor chip having a light receiving surface and an electrode pad on the same surface, a transparent package for enclosing the sensor chip, and a flexible substrate electrically connected to an electrode portion provided on the package. A light receiving sensor, wherein a lens holding member for guiding light to the light receiving surface is adhered to a surface other than the electrode portion and the light receiving portion.

[0051]

As described above, according to the present invention,
Review the configuration from the level of the package that encapsulates and protects the IC part of the focus control sensor, and provides a distance measurement sensor that enables downsizing and weight reduction and enables stable focusing regardless of changes in the camera usage environment. can do.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention;
FIG. 2A is a cross-sectional view illustrating a configuration of a distance measuring sensor, and FIG. 2B is an exploded view illustrating a sensor unit of the distance measuring sensor.

FIG. 2 is a diagram illustrating a general distance measurement sensor.

FIG. 3 is a diagram for explaining a principle of distance measurement of a passive type distance measuring device of a camera.

FIG. 4 is a cross-sectional view illustrating a configuration of a distance measuring sensor according to a second embodiment of the present invention.

FIG. 5 is an exploded view showing a configuration of a distance measuring sensor according to a third embodiment of the present invention.

FIG. 6 is a view showing a process of assembling a distance measuring sensor according to a third embodiment.

FIG. 7 is an exploded view showing a configuration of a distance measuring sensor according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sensor IC, 2, 28 flexible board, 3a, 3b lead frame, 5 wires, 6 resin package, 7, 18a, 18b lens, 8 holding member, 11 subject, 12 distance measuring sensor, 13 photographing lens, 14 CPU, 15 lens driver, 19a, 19b sensor array, 20, 27 'package, 21 lens holder, 25 IC chip, 25a, 25b light receiving surface on chip, 26a, 26b conductive part, 26c, 26d, 26c', 26d 'electrode part 27 package, 27a, 27b glass member, 28a opening, 30, 32 lens holding member, 30a bonding part, 30b projection, 31, 31a, 31b light receiving lens.

Claims (3)

[Claims] 1. A semiconductor chip having a light receiving surface for detecting an image of an object formed via two lenses, a transparent package with leadless electrodes enclosing the semiconductor chip, and the transparent package. And a flexible substrate electrically connected to the electrode of the transparent package, wherein the flexible substrate is configured to guide light from the lens to a light receiving surface of the semiconductor chip. A distance measuring sensor having an opening formed therein. And a holding member for holding the two lenses, wherein the holding member has a protrusion having a thickness equal to or greater than the thickness of the flexible substrate for directly bonding to the package. The distance measuring sensor according to claim 1, wherein 3. A sensor chip having a light receiving surface and an electrode pad on the same surface, a transparent package enclosing the sensor chip except at least the electrode pad, a flexible substrate electrically connected to the electrode pad, A lens holding member that is adhered on the transparent package and guides light from the image of the object formed through two lenses to the light receiving surface. Distance sensor.