JPH1082626A - Fight-coupling apparatus for detection of inclination - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably and highly accurately detect the inclination of an object to be detected. SOLUTION: A light-emitting chip 20 is loaded at a non-receiving area 21z of a photodetecting face 21 of a photodetecting chip 2 so that photodetecting areas 21a-21d are located via an equal distance on a circumference centering an optical axis of the light-emitting chip 20. When a light from the light-emitting chip 20 is reflected at an object to be detected and brought into the photodetecting areas 21a-21d, signals corresponding to an inclination of the object to be detected are output from the photodetecing areas 21a-21d. A detection characteristic to the inclination of the object about an X-axis becomes nearly equal to that to the inclination about a Y-axis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tilt detecting optical coupling device used for a pointing device of a small personal computer.

[0002]

2. Description of the Related Art In recent years, various game machines using computers have been sold. In this type of game machine,
When an operation unit such as a joystick or an input pad is operated, a tilt of the operation unit is detected by a tilt detection sensor, and a character or the like displayed on a display screen is moved based on a detection signal at this time. . As a sensor for detecting the inclination, a contact type sensor that generally involves electrical contact with the operation unit is used. However, since malfunction due to poor contact or the like is likely to occur, there is a problem in reliability. Non-contact (optical) types have been used.

In addition, a mouse is used for moving a cursor, pointing, and the like on a display screen of an output device in a personal computer. This is separate from the personal computer and is used on a flat surface such as an operation panel or a desk. Since it is operated by moving a computer, it cannot be used for a portable small personal computer that has been increasing in demand in recent years. Therefore, some small personal computers have a pointing device arranged between keys in a keyboard. As this pointing device, there is a device in which a hollow stick is placed over an optical tilt detection sensor. By operating the stick, the top surface (reflection surface) of the stick is tilted, and the tilt is detected by the tilt detection sensor. Then, based on the detection signal at this time, cursor movement, pointing, and the like on the display screen are performed.

A conventional optical inclination detecting sensor using a photoelectric conversion element (light receiving / emitting element) is shown in FIGS.
As shown in FIG. 2, a light emitting element (light emitting chip) 1 and a light receiving element (light receiving chip) 2 having four segments of light receiving areas 2a to 2d are die-bonded to a common mounting lead frame 3, and these are connected to a connection lead frame 4. 8 are connected via bonding wires 9 and 10 such as gold wires, and the lens cap 11 covers the light emitting chip 1 and the light receiving chip 2. Each of the lead frames 3 to 8 is embedded in a substrate 12 made of a thermoplastic resin with its surface (the surface on which the chip is mounted and the surface to which the bonding wires 9 and 10 are connected) exposed.

As shown in FIG. 11, the lens cap 11 has a cylindrical side wall 13 and a convex lens 14 closing one end of the side wall 13 integrally formed of a translucent resin. The other open end of the side wall 13 is bonded to the substrate 12 with an adhesive or the like.

The light emitted from the light emitting chip 1 is
The light is condensed by the convex lens 14 of the lens cap 11, is reflected by an operation unit in a game machine or an object S such as a stick in a small personal computer, and is again reflected by the convex lens
The light is condensed at 4 and is incident on each of the light receiving areas 2a to 2d of the light receiving chip 2, and a current proportional to the amount of received light flows from each of the light receiving areas 2a to 2d. The tilt direction and the tilt amount of the detection object S can be detected.

As a method of the arithmetic processing, the current value in the light receiving region 2a is Ia, and the current value in the light receiving region 2b is Ia.
b, current value in light receiving area 2c is Ic, light receiving area 2d
, The X-axis of the object S (FIG. 1)
2) Sx = (Ia + Ic)-(Ib + Id) Similarly, a tilt signal Sy around the Y axis (see FIG. 12) is obtained as Sy = (Ia + Ib)-(Ic + Id). The relationship between the calculation result obtained from the tilt signal Sx at this time and the actual tilt angle around the X axis is shown in FIG.
13A, the relationship between the calculation result obtained from the tilt signal Sy and the actual tilt angle around the Y axis is as shown in FIG. 13B. Therefore, the tilt direction and the tilt amount of the detection target S are obtained from the actual tilt angles in two directions obtained from the calculation results.

In this inclination detecting sensor, the light-emitting chip 1 and the light-receiving areas 2a to 2d of the light-receiving chip 2 are separate and separated from each other, and they are arranged at positions shifted from the optical axis of the optical system. Therefore, as is clear from FIG. 13, the characteristics of the object S around the X-axis and the characteristics around the Y-axis are different, and high-precision tilt detection cannot be performed.

In addition, the above-mentioned difference is related not only to the arrangement of the light emitting / receiving chips 1 and 2 but also to factors such as variations in the distance between the light emitting / receiving chips 1 and 2 and the object S, and lens variations. Even if an attempt was made to make corrections with a processing circuit, the corrections were very difficult. Therefore, it is difficult to apply the present invention to a device that requires high-precision tilt detection, and is poor in versatility.

In order to solve the above problem, Japanese Patent Application Laid-Open No.
In Japanese Patent Application Laid-Open No. 2-69111, as shown in FIG. 14, four light receiving chips 16 are mounted on a substrate 17 so as to be positioned around the light emitting chip 15, and the optical axis of the light emitting chip 15 and the lens There is disclosed an inclination detection sensor in which an optical center is matched. In this structure, each light receiving chip 16 has optical symmetry with respect to the optical axis of the optical system,
The characteristics of the object S around the X-axis and the characteristics around the Y-axis become equal, and the detection accuracy can be improved.

[0011]

However, in the inclination detecting sensor disclosed in JP-A-62-69111,
When the light emitting chip 15 and each light receiving chip 16 are electrically connected to the wiring pattern of the substrate 17 via a bonding wire, light from the light emitting chip 15 is reflected by the bonding wire, and highly accurate tilt detection is performed. There is a fear that they cannot do it.

Since the four light receiving chips 16 are individually arranged around the light emitting chip 15, the light emitting chip 15
However, it is necessary to accurately position each of the light receiving chips 16, and the manufacturing process is complicated and the reliability is poor.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a highly reliable tilt detecting optical coupling device capable of simplifying the manufacturing process and reducing the cost, and capable of stably and accurately detecting a tilt. .

[0014]

According to the present invention, there is provided a light-emitting device, comprising: a light-emitting element; and a light-receiving element having a plurality of light-receiving areas and a non-light-receiving area on a light-receiving surface, and light from the light-emitting element is detected by an object. An optical coupling device that outputs a signal corresponding to the inclination of an object to be detected from each light receiving area when the light is reflected and incident on the light receiving element, wherein the light emitting element is mounted on a non-light receiving area of a light receiving surface of the light receiving element. . Each light receiving area of the light receiving element is arranged at equal intervals on a circumference centered on the optical axis of the light emitting element, and each light receiving area has optical symmetry with respect to the optical axis of the optical system. ing.

Thus, when the object is not tilted, the light emitted from the light emitting element is reflected by the object and uniformly incident on each light receiving area of the light receiving element, and each light receiving area is proportional to the amount of received light. Output a uniform signal. On the other hand, when the detected object is tilted, the amount of light received in each light receiving area changes according to the tilt of the detected object, and a difference occurs in an output signal in each light receiving area. The output signal is calculated by a processing circuit. Then, the actual tilt angle of the object to be detected around the X-axis and the actual tilt angle of the object to be detected around the Y-axis can be obtained, and the tilt direction and the amount of tilt of the object can be detected from these tilt angles.

Further, when the light emitting element is of a constricted type in which light is concentrated and emitted in one direction, or when the light emitting element is arranged in a recess of a light receiving element provided with a light shielding body on a side wall, the light is emitted in a lateral direction from the light emitting element. It is possible to prevent such a problem that the incident light directly enters the light receiving element and is detected as a noise component.

Further, the connection electrode of each light receiving area of the light receiving element is formed at a position most distant from the light emitting element, or the connection electrode of the light emitting element is connected to the non-light receiving area of the light receiving surface of the light receiving element via a bonding wire. When the wiring pattern to be connected is formed, each bonding wire connected to each connection electrode does not straddle the light receiving region, and the length of each bonding wire can be shortened. It can be prevented as much as possible from being reflected by the wire and entering the light receiving region.

[0018]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a tilt detection optical coupling device according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view thereof, FIG. 3 is a plan view of a light emitting chip and a light receiving chip, and FIG. FIG.

With reference to these drawings, the tilt detection sensor (tilt detecting optical coupling device) of the present embodiment is disposed on an operation unit in a game machine or an object S such as a stick in a small personal computer. , A light emitting element (light emitting chip) 20 composed of a light emitting diode, and a light receiving surface 21
A light receiving element (light receiving chip) 22 composed of a four-division photodiode having four segments of light receiving areas 21a to 21d and a non-light receiving area 21z, and a lens cap 23 covering these elements.

As shown in FIGS. 1, 2, and 4, the light receiving chip 22 is bonded to a mounting lead frame 30 with a conductive paste 31 such as an Ag paste. Each light receiving area 21
Reference numerals a to 21d are square and have the same area, are arranged at four diagonal corners of the square light receiving surface 21, and are provided with connection electrodes (pads) 32a to 32d for the respective light receiving regions 21a to 21d.
2d is electrically connected to connection lead frames 34 to 37 via bonding wires 33 such as gold wires.

In the non-light receiving area 21z of the light receiving chip 22 other than the light receiving areas 21a to 21d, a convex aluminum chip mounting wiring pattern 40 and an aluminum relay wiring formed in a rectangular wiring pattern are provided. Pads 41 are provided.

As shown in FIG. 3, the mounting wiring pattern 40 is disposed at the center of the light receiving surface 21 equidistant from each of the light receiving areas 21a to 21d, and the light emitting chip 20 is adhered by the conductive paste 42. Part 40a and wiring part 4 connected to the mounting part 40a and arranged between the light receiving regions 21a and 21b.
0b. The relay pad 41 is disposed between the light receiving regions 21 c and 21 d, and the connection electrode (pad) 20 a of the light emitting chip 20 is electrically connected via the bonding wire 43.

Accordingly, the light emitting chip 20 on the mounting portion 40a of the mounting wiring pattern 40 is provided in each of the light receiving regions 21a to 21a.
It is located at the center of the light receiving surface 21 equidistant from 21d. In other words, each of the light receiving areas 21a to 21d is
Are arranged at equal intervals on a circumference centered on the optical axis.

If the light receiving surface 21 of the light receiving chip 22 is made of only a normal silicon oxide film, a short circuit may occur due to the use of the conductive paste 42. Therefore, as shown in FIG. Except for the regions 21a to 21d and the wiring pattern, a film 44 made of light-shielding polyimide or the like is applied to insulate and shield light. This allows
A short circuit when the light emitting chip 20 is adhered with the conductive paste 42 can be prevented, and the light receiving regions 21a to 2a can be prevented.
It is also possible to prevent such a problem that light hitting other than 1d is detected as a noise component.

The mounting wiring pattern 40 is electrically connected to the mounting lead frame 30 via the bonding wire 45, and the relay pad 41 is electrically connected to the connection lead frame 47 via the bonding wire 46. Have been. Each of the lead frames 30, 34 to
As shown in FIG. 2, reference numerals 37 and 47 denote a substrate 50 made of a thermoplastic resin such as polyphenylsulfite in a state where its surface (the surface on which the chip is mounted and the surface to which the bonding wires 33, 45 and 46 are connected) is exposed. It is in a state embedded in.

In the lens cap 23, a cylindrical side wall 51 and a convex lens 52 for closing one end of the side wall 51 are integrally formed of a translucent resin such as acrylic polycarbonate. Then, the side wall 51 is adjusted so that the optical center of the convex lens 52 and the optical axis of the light emitting chip 20 coincide with each other.
Open end is adhered to the substrate 50 by an adhesive or the like.

With the above-described configuration, each of the light receiving areas 21a to 21d of the light receiving chip 22 maintains optical symmetry with respect to the optical axis of the optical system. It is an ideal arrangement. However, light from the light emitting chip 20 is reflected by the bonding wire and is incident on the light receiving regions 21a to 21d, and some of the light receiving regions 21a
21d, the light from the light emitting chip 20 is directly transmitted to the light receiving area 21a of the light receiving chip 22.
To 21d, and is detected as a noise component. Therefore, in the tilt detection optical coupling device of the present embodiment, various measures are taken to solve these problems.

First, as a measure to prevent the light from the light emitting chip 20 from being reflected by the bonding wires and entering the light receiving areas 21a to 21d, the pads 32a to 32d of the light receiving areas 21a to 21d of the light receiving chip 22 are used. It is formed at the corner of each of the light receiving areas 21a to 21d furthest from the light emitting chip 20. Thereby, each of the pads 32a-32
d is connected to the light receiving region 2
1a to 21d, for example, the pad 32a
The light from the light emitting chip 20 is reflected by each bonding wire 33 and the light receiving regions 21a to 2d are compared with the case where the light receiving regions 21a to 21d are formed near the center of the light receiving regions 21a to 21d.
The ratio of incidence on 1d can be reduced.

As another countermeasure, a relay pad 41 is formed in the non-light receiving area 21z of the light receiving chip 22,
The pad 20a of the light emitting chip 20 and the relay pad 41 are connected via a bonding wire 43, and the relay pad 41 and the connection lead frame 47 are connected via a bonding wire 46. As a result, the bonding wires 43 and 46 do not straddle the light receiving regions 21a to 21d, and the lengths of the bonding wires 43 and 46 can be reduced.
The ratio of the light from the light emitting chip 20 reflected by the bonding wires 43 and 46 and incident on the light receiving regions 21a to 21d is smaller than that in the case where the connection lead frame 47 is connected to the connection lead frame 47 via the bonding wire. can do. In addition, stable assembly properties can be realized.

Next, as a measure for preventing light from the light emitting chip 20 from directly entering the light receiving regions 21a to 21d of the light receiving chip 22, a normal light emitting chip 20A formed by epitaxial growth is used as the light emitting chip 20. Instead, a current confinement type light emitting chip is used. This is because the intensity distribution of the emitted light is completely different between the normal light emitting chip 20A and the current confinement type light emitting chip 20, and the normal light emitting chip 20A emits in the lateral direction as shown in FIG. The amount of light is considerably large, and the light receiving regions 21a-2
While light is likely to be directly incident on 1d, the current confinement type light emitting chip 20 emits light concentrated in one direction in front as shown in FIG. 21
This is because it is unlikely that light is directly incident on a to 21d.

When a normal light emitting chip 20A is used, as shown in FIG. 6, an etching process is performed on the light receiving surface 21 of the light receiving chip 22 at the center of the light receiving surface 21 on which the normal light emitting chip 20A is mounted. The recess 60 is formed in advance, and a light shielding body 61 is provided on the wall surface of the recess 60.
The light-shielding body 61 has a light-emitting chip 20A
It is made by coating a material having a high light reflectance while shielding light from the light source into a thin film. Then, a chip mounting wiring pattern 40 and a relay pad 41 are formed, and the light emitting chip 20A is mounted in the recess 60. As a result, the light emitted laterally from the light emitting chip 20A is reflected forward without passing through the inside of the light receiving chip 22 and reaching the light receiving areas 21a to 21d.
The same effect as when 0 is used can be obtained.

Further, as shown in FIG.
0A may be surrounded by a light shielding wall 70. The light shielding wall 70 is configured to shield light emitted from the light emitting chip 20A in the lateral direction and to reflect the light upward. With this, the same effect as when the current confinement type light emitting chip 20 is used can be obtained.

In the above configuration, when the object S such as the operation unit in the game machine or the stick in the small personal computer is not tilted, the light emitting chip 20 is used.
Is emitted from the convex lens 52 of the lens cap 23.
And is reflected by the object S to be collected again by the convex lens 52. Each of the light receiving areas 21a to 21d of the light receiving chip 22
And a uniform current proportional to the amount of received light flows from each of the light receiving areas 21a to 21d.

On the other hand, when the object S is tilted, the amount of light received by the light receiving chip 22 changes according to the inclination of the object S, and a current proportional to the amount of light flows from each of the light receiving areas 21a to 21d. Each current value is arithmetically processed by a processing circuit provided in a game machine or a small personal computer, so that the direction and amount of inclination of the detection target S can be detected.

As a method of the arithmetic processing, the light receiving area 21a
, The current value in the light receiving area 21b is IB, the current value in the light receiving area 21c is IC, and the current value ID in the light receiving area 21d is X.
SX = (IA + IC)-(IB + ID) Similarly, a tilt signal SY around the Y axis (see FIG. 8) is obtained as SY = (IA + IB)-(IC + ID). . The relationship between the calculation result obtained from the tilt signal SX at this time and the actual tilt angle around the X axis is shown in FIG.
As shown in FIG. 9A, the characteristic changes linearly up to a certain angle range, and the relationship between the calculation result obtained from the inclination signal SY and the actual inclination angle around the Y axis is shown in FIG.
As shown in FIG. 7, as in the case of the X-axis, the characteristic changes linearly up to a certain angle range, and the characteristics in these two directions are almost equal. Then, the inclination direction and the amount of inclination of the detection target S are obtained from the actual two inclination angles obtained from the calculation results.

As described above, in the tilt detecting optical coupling device of the present embodiment, the light emitting chip 20 is mounted on the light receiving chip 22 having the light receiving areas 21a to 21d, so that the light emitting chip and the light receiving chip Compared to the case where each light receiving region is separated from each other, stable and highly accurate tilt detection can be performed. In addition, as compared with the case where a plurality of light receiving chips are individually arranged around the light emitting chip as in the related art, the light receiving areas 21a to 21d of the light emitting chip 20 and the light receiving chip 22 can be accurately positioned with a simple operation. Can be. Therefore, the manufacturing process can be simplified and the cost can be reduced, and a highly reliable tilt detecting optical coupling device can be provided.

Each light receiving area 21a of the light receiving chip 22
21 d are arranged at equal intervals on the circumference around the optical axis of the light emitting chip 20, and the optical axis of the convex lens 52 of the lens cap 23 coincides with the optical axis of the light emitting chip 20. Each light receiving area 21a to 21d of the light receiving chip 22 has optical symmetry with respect to the optical axis of the system, and has a characteristic with respect to the inclination of the detection object S around the X axis and a characteristic with respect to the inclination around the Y axis. Are equivalent to each other, and more stable and accurate tilt detection is possible.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that many modifications and changes can be made to the above-described embodiment within the scope of the present invention. For example, the light receiving chip is not limited to a four-division photodiode,
What is necessary is just to have a some light-receiving area so that the inclination of a to-be-detected object can be detected. In addition, the shape and arrangement of each light receiving region of the light receiving chip are not limited to the above-described embodiment. For example, each light receiving region may be circular and arranged in a cross shape so as to surround the light emitting chip 20.

[0039]

As is apparent from the above description, according to the present invention, since the light-emitting element is mounted on the light-receiving element having the light-receiving area, the light-emitting chip and each light-receiving area of the light-receiving chip are separated from each other as in the prior art. Compared with a case where the user is away from the body, stable and accurate tilt detection can be performed. In addition, the light-emitting element and each light-receiving region of the light-receiving element can be accurately positioned by a simple operation, compared with a case where a plurality of light-receiving chips are individually arranged around the light-emitting chip as in the related art. Can be simplified and the cost can be reduced, and an optical coupling device for tilt detection with high reliability can be provided.

When the light receiving areas of the light receiving element are arranged at equal intervals on a circumference centered on the optical axis of the light emitting element, each light receiving area of the light receiving element is optically symmetric with respect to the optical axis of the optical system. Characteristic of the object with respect to the tilt around the X axis and Y
The characteristics with respect to the inclination around the axis are equivalent, and more stable and accurate inclination detection is possible.

Further, when the light emitting element is of a constricted type in which light is concentrated and emitted in one direction, or when the light emitting element is arranged in a recess of a light receiving element provided with a light shielding body on a side wall, the light emitting element can be moved in a lateral direction from the light emitting element. Can be prevented from being directly incident on each light receiving region of the light receiving element and detected as a noise component, and more stable and accurate tilt detection can be performed.

Further, the connection electrode of each light receiving area of the light receiving element is formed at a position farthest from the light emitting element, or the connection electrode of the light emitting element is connected to the non-light receiving area of the light receiving surface of the light receiving element via a bonding wire. When the wiring pattern to be connected is formed, each bonding wire connected to each connection electrode does not straddle the light receiving region, and the length of each bonding wire can be shortened. Reflection by the wire and incidence on the light receiving region can be prevented as much as possible, and more stable and accurate tilt detection can be performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a tilt detection optical coupling device according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the same.

FIG. 3 is a plan view of a light emitting chip and a light receiving chip.

FIG. 4 is a longitudinal sectional view of a light receiving chip.

5A is a diagram illustrating an intensity distribution of emitted light in a normal light emitting chip, and FIG. 5B is a diagram illustrating an intensity distribution of emitted light in a current confinement type light emitting chip;

FIG. 6 is a longitudinal sectional view of a light receiving chip of an optical coupling device for tilt detection according to another embodiment.

FIG. 7 is a longitudinal sectional view of a light receiving chip of an optical coupler for tilt detection according to another embodiment.

FIG. 8 is a diagram showing a center of inclination of an object to be detected;

9A is a diagram illustrating a relationship between a tilt signal around an X axis and an actual tilt angle, and FIG. 9B is a diagram illustrating a relationship between a tilt signal around a Y axis and an actual tilt angle.

FIG. 10 is a cross-sectional view of a conventional tilt detection optical coupling device.

FIG. 11 is a longitudinal sectional view of the same.

FIG. 12 is a diagram showing a center of inclination of an object to be detected;

13A is a diagram illustrating a relationship between a tilt signal around an X axis and an actual tilt angle, and FIG. 13B is a diagram illustrating a relationship between a tilt signal around a Y axis and an actual tilt angle.

FIG. 14 is a plan view of a light emitting chip and a light receiving chip in another conventional optical coupling device for detecting inclination.

[Explanation of symbols]

 REFERENCE SIGNS LIST 20 light emitting element 20 a light emitting element connection electrode 21 light receiving surface 21 a to 21 d light receiving area 21 z non-light receiving area 22 light receiving element 32 a to 32 d connection electrode 41 for each light receiving area 41 relay pad 43 bonding wire 60 dent 61 light shielding body S detected Stuff

Claims (6)

[Claims] 1. A light-emitting element, comprising: a light-receiving element having a plurality of light-receiving regions and a non-light-receiving region on a light-receiving surface; when light from the light-emitting element is reflected by an object and enters the light-receiving element Wherein the light emitting element is mounted in a non-light receiving area on a light receiving surface of the light receiving element, wherein the light emitting element is mounted on a non-light receiving area of the light receiving surface of the light receiving element. Coupling device. 2. The optical coupling device for tilt detection according to claim 1, wherein the respective light receiving areas of the light receiving element are arranged at equal intervals on a circumference centered on an optical axis of the light emitting element. . 3. The tilt detecting optical coupling device according to claim 1, wherein the light emitting element is of a constriction type that emits light in one direction by concentrating the light in one direction. 4. The light-emitting element is disposed in a recess formed in a non-light-receiving region of a light-receiving surface of the light-receiving element, and a light-shielding body that shields light from the light-emitting element is provided on a side wall of the recess. The optical coupling device for tilt detection according to claim 1 or 2, wherein: 5. The optical coupling for tilt detection according to claim 1, wherein a connection electrode of each light receiving region of the light receiving element is formed at a position farthest from the light emitting element. apparatus. 6. A wiring pattern is formed in a non-light receiving area on a light receiving surface of the light receiving element, and a connection electrode of the light emitting element is connected to the wiring pattern via a bonding wire. 5. The optical coupling device for tilt detection according to any one of 5.