JPH11242926A - Photoelectric key operation array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the influence of reflection by an infrared ray transmission plate and the influence of dispersion of sensitivity caused by the dispersion of a light receiving element or the like. SOLUTION: A light emitting element 1 and a light receiving element 2 which are received in chambers 3a, 3b of a shading body 3, respectively and mounted on a printed circuit board 4 to constitute a photoelectric type key. The light receiving element 2 is installed by being tilted at a predetermined angle with respect to the printed circuit board 4 with its light receiving surface oriented in a direction opposite to the light emitting element 1. When a screening object 9 approaches an infrared ray transmission plate 7, infrared rays from the light emitting element 1 are irregularly reflected and sensed by the light receiving element 2. When the screening object 9 separates from the infrared ray transmission plate 7, the light receiving quantity of the infrared rays which is acutely incident on the infrared ray transmission plate 7 from the light emitting element 1 is reduced, so that the influence of the light directly reflected by the infrared ray transmission plate 7 can be significantly reduced. In particular, although the dispersion of the sensitivity of the light receiving element 2 or the like is increased by increasing the luminance of the light emitting element 1, the influence by the dispersion of the sensitivity can effectively be restrained even in this case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric key operation array, and more particularly, to an infrared light transmitting element, in which an infrared light emitting element and an infrared light receiving element are juxtaposed on a lower surface of an infrared light transmitting plate, and a finger is provided on an upper surface of the infrared light transmitting plate. The present invention relates to a photoelectric key operation array using infrared light which is operated by a shield such as the above.

[0002]

2. Description of the Related Art A flow meter, which is indispensable for measuring and trading petroleum products, chemical liquids, food-grade liquids, etc., for improving plant efficiency and for operation control, etc., is connected to a flow pipe and outputted according to flow velocity. This is a measuring device that detects a flow rate (flow velocity), converts it into an electric quantity, and displays it on an arithmetic unit. Normally, the arithmetic unit (converter) has a visible glass plate, and various key operations including a setting circuit for setting parameters such as meter constants and flow rate settings, and adjusting zero points and the like. It has an array, of which a photoelectric keying array is often used.

The photoelectric key operation array is provided on the lower surface of an infrared transmitting plate that transmits infrared light, and an infrared light emitting element that emits light toward the infrared transmitting plate, and an infrared light emitting element that is juxtaposed on the lower surface of the infrared transmitting plate. An infrared light receiving element for receiving reflected light is provided.When a shield is brought close to the upper surface of the infrared transmission plate, the infrared light emitted from the lower surface of the infrared transmission plate is irregularly reflected by the shield, and the diffused infrared light is reflected by the infrared light. Detected by a light receiving element and output as a photoelectric conversion signal, usually provided with a plurality of keys.

FIG. 3 is a partial sectional view of a conventional photoelectric key operation array. In the figure, 21 is an infrared light emitting element, 22 is an infrared light receiving element, 23 is an infrared impermeable shield, 24 is a light guide, 25 Is an infrared transmitting plate, and 26 is a shield such as a finger.

[0005] The infrared light emitting element 21 and the infrared light receiving element 22 are arranged on the lower surface side of the infrared transmitting plate 25, and an infrared impermeable shield 23 is provided between the infrared light emitting element 21 and the infrared light receiving element 22. The infrared rays radiated from 21 do not directly reach the infrared light receiving element 22. The infrared light emitted from the infrared light emitting element 21 is focused on the infrared transmission plate 25 in the vertical direction.

The infrared light receiving element 22 is accommodated in a cylindrical light guide 24 for shielding infrared light, and considering only the refraction and surface reflection of the infrared transmitting plate 25, only infrared light irregularly reflected by a shield 26 such as a finger is received by the infrared light receiving element. The angle of the light guide 24 with respect to the lower surface of the infrared transmission plate 25 is determined so that the light reaches the infrared light receiving element 22 and the other infrared light does not reach the infrared light receiving element 22.

[0007] The photoelectric key operation array having this configuration has a drawback that it is directly affected by variations in the performance of components, and an invention has been made to improve this disadvantage (Japanese Patent Application No. 9-76).
No. 821). Techniques of the present invention (hereinafter referred to as conventional techniques)
When a finger approaches an upper surface of an infrared transmitting plate that transmits infrared light, a photoelectric key operating array including a plurality of photoelectric keys based on reflected light reflected on the lower surface of the infrared transmitting plate. An infrared light emitting element installed in a first room on the lower surface of the infrared transmitting plate, an infrared light receiving element housed in a second room juxtaposed to the first room and receiving infrared light from the infrared light emitting element, An infrared absorbing plate provided on the inner surface of the first room and an infrared reflecting plate provided on the inner surface of the second room,
An effective luminous flux can be obtained, the efficiency of collecting irregularly reflected infrared rays on the infrared light receiving element is increased, and the detection sensitivity can be improved.

FIG. 4 is a partial sectional view of a conventional photoelectric key operation array. In the figure, reference numeral 31 denotes a photoelectric key operation array, 32 denotes an infrared transmitting plate, 33 denotes an infrared transmitting filter,
34 is a light shielding wall, 35 is an infrared light emitting element, 36 is an infrared light receiving element, 37 is an absorbing plate, 38 is a reflecting plate, and 39 is a shield such as a finger.

In the photoelectric key operation array 31 shown in FIG. 4, infrared rays emitted from the infrared light emitting element 35 pass through the infrared transmission filter 33 and the infrared transmission plate 32,
Shielding object 3 such as a finger which is brought close to the upper surface of infrared transmitting plate 32
At 9, the light flux of the irregularly reflected infrared light again passes through the infrared transmitting plate 32 and the infrared transmitting filter 33, and is condensed as direct light and the reflected light reflected by the reflecting plate 38 in the receivable range of the infrared light receiving element 36.

[0010]

As a result of further studies on the prior art, the present inventor has found that infrared rays from an infrared light emitting element diffuse in all directions upward, so that a glass plate (infrared transmitting plate) is used. The reflected light based on the luminous flux hitting the acute angle eventually reaches the infrared light receiving element, and the luminance of the infrared light emitting element and the sensitivity of the infrared light receiving element are inevitably varied. In particular, since the luminance is proportional to the magnitude of the forward current, It has been found that an error in the forward current affects the luminance, and these factors together cause variations in switch sensitivity.

The present invention has been made in view of the above circumstances, and provides a photoelectric key operation array which is hardly affected by an infrared ray which strikes an infrared transmitting plate at an acute angle and which is not affected by variations in switch sensitivity. Things.

[0012]

According to the first aspect of the present invention, an infrared ray radiated from a lower surface direction of the infrared transmitting plate is irregularly reflected by bringing a shielding object close to an upper surface of the infrared transmitting plate that transmits infrared light. In a photoelectric key operation array including a plurality of photoelectric keys that are operated based on the reflected light of the infrared light that is irregularly reflected, the photoelectric key is provided on a lower surface of the infrared light transmitting plate and faces the infrared light transmitting plate. An infrared light emitting element that emits infrared light, an infrared light receiving element that receives the infrared light that is irregularly reflected by a shield from the upper surface of the infrared light transmitting plate, and a first light emitting element that includes the infrared light emitting element
And a light-shielding body having a second room for installing the infrared light receiving element, wherein the infrared light receiving element faces the light receiving surface in the opposite direction to the infrared light emitting element, and installs the second room. It is characterized by being installed at a predetermined angle with respect to the surface, so that it is hardly affected by a light beam that strikes the infrared transmitting plate at an acute angle, and the influence of variations in switch sensitivity is eliminated.

According to a second aspect of the present invention, in the first aspect, a surface of the inner surface of the second room facing the light receiving surface of the infrared light receiving element is an infrared reflecting surface for reflecting the infrared light. Thus, only the infrared light of the required path light reaches the infrared light receiving element.

According to a third aspect of the present invention, in the first or second aspect of the invention, at least a portion of the upper surface of the light shield between the first room and the second portion is an infrared absorbing surface. Thus, unnecessary reflection of infrared light toward the infrared light receiving element is prevented.

[0015]

FIG. 1 is a cross-sectional view of a photoelectric key portion of a photoelectric key operation array showing one embodiment of the present invention. In the drawing, reference numeral 1 denotes an infrared light emitting element such as an LED, and 2 denotes a photo IC. Etc., 3 is a light shield, 3a and 3b are rooms, 4
Is a printed board, 5 is an upper surface of a light shield, 6 is an infrared reflecting surface of the room 3b, 7 is an infrared transmitting plate, 8 is an infrared transmitting filter, 9 is a shield such as a finger, and L is an optical path.

The photoelectric key operation array includes an infrared transmitting plate 7.
A surface-parallel infrared transmission filter 8 is arranged on the lower surface of the light-transmitting filter 8, and a pair of infrared light-emitting elements 1 and infrared light-receiving elements 2 are juxtaposed in a light shielding body 3 on the lower surface side of the infrared transmission filter 8. These are juxtaposed.

The infrared transmitting plate 7 is a glass plate which satisfies, for example, an explosion-proof standard and has a thickness of, for example, 5 mm or more that can withstand an explosion and an external impact. Has become. The infrared transmission plate 7 blocks light other than infrared light, and prevents malfunction due to sunlight or the like. The infrared transmission filter 8 blocks light other than infrared light and prevents malfunction due to sunlight or the like.

The light-shielding body 3 is, for example, an opaque resin molding material, and has a room 3a in which the infrared light emitting element 1 is installed and a room 3b in which the infrared light receiving element 2 is installed.
Are blocked so that the infrared light receiving element 2 does not directly receive infrared light emitted from the infrared light emitting element 1.
In the room 3a, an infrared light emitting element 1 that emits infrared light such as an LED (Light Emittion Diode) is installed on a printed circuit board 4. In the room 3b, an infrared light receiving element 2 is installed on the printed circuit board 4. The light receiving surface is attached to the infrared light emitting element 1 in a direction opposite to that of the infrared light emitting element 1 and is inclined at a predetermined angle (α) with respect to the printed circuit board 4.

In the photoelectric key operation array having the above-described structure, infrared rays emitted from the infrared light emitting element 1 pass through the infrared light transmitting filter 8 and the infrared light transmitting plate 7 to shield a finger or the like close to the upper surface of the infrared light transmitting plate 7. The irregularly reflected infrared light from the object 9 passes through the infrared transmitting plate 7 and the infrared transmitting filter 8 again, and reaches the infrared light receiving element 2 as infrared light reflected on the reflecting surface 6 of the room 3b.

At this time, since the infrared light receiving element 2 is attached with its light receiving surface directed in the opposite direction to the infrared light emitting element 1 and inclined at a predetermined angle (α) with respect to the printed circuit board 4, it is shielded. When the object 9 is at a distance (position A) that is insensitive to the infrared transmitting plate 7, the infrared light emitted from the infrared light emitting element 1 does not reach the shield 9, and the infrared light reflected irregularly on the lower surface of the infrared transmitting plate 7. Key does not reach the infrared light receiving element 2, the key is in the OFF state. When the shield 9 approaches the sensitive distance (position B) from the infrared transmitting plate 7, the infrared light emitted from the infrared light emitting element 1 is irregularly reflected on the upper surface of the infrared transmitting plate 7, and further reflected on the reflecting surface 6 of the room 3b. The key is turned on by being reflected and reaching the infrared light receiving element 2. In particular, if the reflection surface 6 is white, reflection of infrared rays from the infrared light emitting element 1 is promoted, so that a required light flux can be secured. As a result, it is less likely to be affected by a light beam that strikes the infrared transmitting plate 7 at an acute angle, and it is possible to receive required infrared light that has been re-reflected by the reflecting surface 6 of the room 3b. This is effective when the luminance of the infrared light emitting element 1 is increased. Angle α
Is preferably fixed to the printed circuit board 4 at an acute angle, preferably α = 45 ° to 60 °.

FIG. 2 is a sectional view of a photoelectric key portion of a photoelectric key operation array showing another embodiment of the present invention.
0 is a black tape and 11 is a black tube. The same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The black tape 10 is affixed to the entire upper surface 5 of the light shield 3 or at least between the first room and the second room. The black tube 11 is attached to the room 3 a in which the infrared light emitting element 1 is stored so as to surround the infrared light emitting element 1.

With the configuration shown in FIG. 2, of the infrared light emitted from the infrared light emitting element 1 by the black tape 10, unnecessary reflection of infrared light toward the infrared light receiving element 2 is prevented, and the infrared light emitting element 1 is accommodated by the black tube 11. Of the infrared light emitted from the infrared light emitting element 1 in the room 3a, unnecessary infrared light other than the infrared light transmitting plate 7 is absorbed.

[0023]

According to the first aspect of the present invention, by bringing the shielding object close to the upper surface of the infrared transmitting plate that transmits infrared light, the infrared radiation radiated from the lower surface direction of the infrared transmitting plate is diffused and reflected. In a photoelectric key operation array including a plurality of photoelectric keys operated based on the reflected light of the infrared light, the photoelectric key is provided on a lower surface of the infrared transmission plate, and transmits the infrared light toward the infrared transmission plate. An infrared light emitting element that emits light; an infrared light receiving element that receives the infrared light that is irregularly reflected by a shield from the upper surface of the infrared transmitting plate; a first room in which the infrared light emitting element is installed; and a second room in which the infrared light receiving element is installed. The infrared light receiving element faces the light receiving surface in the opposite direction with respect to the infrared light emitting element, and
Because it is installed at a predetermined angle to the installation surface of the room, it is less susceptible to the luminous flux that strikes the infrared transmitting plate at an acute angle, and receives only the required infrared light that has been re-reflected by the reflection surface of the light-shielding room. can do. For this reason, even if the luminance of the infrared light emitting element is increased, the light is focused on the infrared light receiving element with certainty. Switching operation can be performed.

According to the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, the surface of the inner surface of the second room facing the light receiving surface of the infrared light receiving element is reflected by the infrared light reflecting the infrared light. Since the surface is a surface, unnecessary light can be prevented from entering the infrared light receiving element, and only infrared light of a required light flux can reliably reach the infrared light receiving element.

According to the invention of claim 3, claim 1 or 2
In addition to the effect of the invention, since at least the upper surface of the light shield between the first room and the second room is an infrared absorbing surface, unnecessary reflection of infrared light toward the infrared light receiving element is prevented. can do.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a photoelectric key portion of a photoelectric key operation array showing one embodiment of the present invention.

FIG. 2 is a sectional view of a photoelectric key portion of a photoelectric key operation array showing another embodiment of the present invention.

FIG. 3 is a partial cross-sectional view of a conventional photoelectric key operation array.

FIG. 4 is a partial cross-sectional view of another conventional photoelectric key operation array.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Infrared light emitting element, 2 ... Infrared light receiving element, 3 ... Light shielding body, 3a, 3b ... Room, 4 ... Printed circuit board, 5 ... Upper surface of light shielding body, 6 ... Reflection surface, 7 ... Infrared transmission plate, 8 ... Infrared transmission Filter, 9 ... Shielding material such as finger, 10 ... Black tape,
11: black tube, 21: infrared light emitting element, 22: infrared light receiving element, 23: infrared opaque shield, 24 ...
Light guide, 25: infrared transmitting plate, 26: shield such as finger, 31: photoelectric key operation array, 32: infrared transmitting plate, 33: infrared transmitting filter, 34: light shielding wall, 35 ...
Infrared light emitting element, 36: infrared light receiving element, 37: absorbing plate, 38: reflecting plate, 39: shielding object such as finger, L: optical path.

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[Procedure amendment]

[Submission date] March 8, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

[0012]

According to the first aspect of the present invention, an infrared ray radiated from a lower surface direction of the infrared transmitting plate is irregularly reflected by bringing a shielding object close to an upper surface of the infrared transmitting plate that transmits infrared light. In a photoelectric key operation array including a plurality of photoelectric keys that are operated based on the reflected light of the infrared light that is irregularly reflected, the photoelectric key is provided on a lower surface of the infrared light transmitting plate and faces the infrared light transmitting plate. An infrared light emitting element that emits infrared light, an infrared light receiving element that receives the infrared light that is irregularly reflected by a shield from the upper surface of the infrared light transmitting plate, and a first light emitting element that includes the infrared light emitting element
And a light-shielding body having a second room for installing the infrared light receiving element, wherein the infrared light receiving element faces the light receiving surface in the opposite direction to the infrared light emitting element, and installs the second room. When inclined at a predetermined angle to the surface,
The second room is opposite to a light receiving surface of the infrared light receiving element.
The facing surface is an infrared reflecting surface that reflects the infrared light.
This feature makes it possible to apply an acute angle to the infrared transmitting plate.
Difficult to be affected by dripping light flux, variation in switch sensitivity
And eliminates only the infrared light of the required path light.
It reaches the infrared light receiving element .

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

According to a second aspect of the present invention, in the first aspect of the present invention, at least the first room and the front of the upper surface of the light shield are provided.
The second feature is that an infrared absorbing surface is provided between the room and the room.
Therefore, unnecessary infrared rays are reflected toward the infrared receiving element.
It is designed to prevent shooting.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Deleted

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

[0023]

According to the first aspect of the present invention, a shielding object is brought close to the upper surface of an infrared transmitting plate that transmits infrared light.
In a photoelectric key operation array including a plurality of photoelectric keys for irregularly reflecting infrared light radiated from the lower surface direction of the infrared transmitting plate and operating based on the reflected light of the irregularly reflected infrared light, the photoelectric key operation includes: An infrared light emitting element provided on a lower surface of the infrared transmitting plate, for emitting the infrared light toward the infrared transmitting plate, an infrared light receiving element for receiving the infrared light irregularly reflected by a shield from the upper surface of the infrared transmitting plate, and the infrared light emitting element A light-shielding body having a first room for installing an element and a second room for installing the infrared light-receiving element, wherein the infrared light-receiving element faces the light-receiving surface in a direction opposite to the infrared light-emitting element, and In addition to being inclined at a predetermined angle with respect to the installation surface of the second room,
The room facing the light receiving surface of the infrared light receiving element
Since the infrared reflection surface reflects infrared light,
Being less susceptible to luminous flux that strikes the superplate at an acute angle
In addition, the required infrared light that has been re-reflected by the reflective surface of the light-shielding room
Can only receive light, and therefore infrared
Even if the brightness of the
Therefore, products such as infrared light emitting elements and infrared light receiving elements
When there is variation in switch sensitivity due to variation in
However, accurate switching operation can be performed. Sa
A light receiving surface of an infrared light receiving element on an inner surface of the second room;
The surface facing the surface is an infrared reflecting surface that reflects infrared light
This prevents unnecessary light from entering the infrared light receiving element,
Ensures that only the infrared rays of the light beam reach the infrared receiving element
It has an effect that can be done.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction contents]

According to a second aspect of the present invention, in addition to the effects of the first aspect of the invention , at least a first surface of the upper surface of the light shielding body is provided.
Since the space between the room and the second room was an infrared absorbing surface,
Prevents unnecessary reflection of infrared light toward the infrared light receiving element
be able to

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0025

[Correction method] Deleted

Claims (3)

[Claims] 1. An infrared light radiating from a lower surface direction of the infrared transmitting plate is irregularly reflected by bringing a shielding object close to an upper surface of the infrared transmitting plate transmitting the infrared light, based on the reflected light of the irregularly reflected infrared light. In a photoelectric key operation array including a plurality of photoelectric keys to be operated, the photoelectric key is provided on a lower surface of the infrared transmitting plate, and an infrared light emitting element that emits the infrared light toward the infrared transmitting plate,
An infrared light receiving element for receiving the infrared light irregularly reflected by a shield from the upper surface of the infrared transmitting plate, and a light shield having a first room for installing the infrared light emitting element and a second room for installing the infrared light receiving element. A photoelectric key, wherein the infrared light receiving element is installed such that the light receiving surface is oriented in the opposite direction to the infrared light emitting element and is inclined at a predetermined angle with respect to the installation surface of the second room. Operational array. 2. The photoelectric key operation according to claim 1, wherein a surface of the inner surface of the second room that faces the light receiving surface of the infrared light receiving element is an infrared reflecting surface that reflects the infrared light. array. 3. The method according to claim 1, wherein at least the first portion of the upper surface of the light shielding body is provided.
3. The photoelectric key operation array according to claim 1, wherein an infrared absorbing surface is provided between the room and the second part. 4.