JPH08129600A - Optical information reader - Google Patents

Abstract

PURPOSE: To provide an optical information reader which is small-sized, lightweight, and low in cost by realizing a focusing device and a range finder which are small-sized, lightweight, and low in cost while having an extremely large read range. CONSTITUTION: This optical information reader consists of a light source 2, the focusing device 3, an oscillatory mirror type scanning device 4, a photodetection optical system 5, a photoelectric converter 7, a signal processing part 8, and the range finder 6. The focusing device 3 consists of a focusing lens, a focusing lens position detecting means, a focusing lens moving means, and a focusing lent position servo circuit 34. The focusing lens position servo circuit 34 stops the focusing lens moving means when the position detection signal from the focusing lens position detecting means matches the distance measurement signal from the range finder 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light beam scanning type optical information reader for reading optical information using a light beam. In particular, the present invention relates to a variable focus type light beam scanning optical information reading device for reading optical information accurately from a near point to a far point over a long depth.

[0002]

2. Description of the Related Art In the physical distribution field, for example, the distance between a fixed scanner and a label is generally not constant. For this reason, autofocus fixed scanners have been awarded (July 1992).
Published by Kogyo Kogyo Kenkyukai Co., Ltd., K. Asano, 1st ed., "Future Bar Code Systems", pp. 203-204). FIG. 18 is a diagram showing the principle of operation of such a conventional automatic focusing type fixed scanner. The automatic focus type fixed scanner of that kind includes a casing 1, a laser element 2, a converging optical system 3, a polygon mirror device 4, and a light receiving optical system (not shown).
And a rangefinder 6. The laser element 2, the focusing optical system 3, the polygon mirror device 4, and the light receiving optical system are
It is stored in the housing 1. However, only the rangefinder 6
It is not housed in the housing 1 but is arranged outside.

The converging optical system comprises a converging lens 31, a converging lens moving mechanism (not shown), a converging lens position servo mechanism and the like. Servo potentiometer 3P
Is a part of the convergent lens position servo mechanism. The movable portion of the servo potentiometer 3P is connected to the lens moving mechanism and constitutes the movable portion of the converging optical system together with the converging lens 31 and the lens moving mechanism. The distance signal DS from the distance meter 6 is given to the servo potentiometer 3P. The converging lens position servomechanism adjusts the position of the converging lens 31 to bring its focus to the label surface.

FIG. 19 is a schematic diagram showing an example of a physical distribution sorting system using a conventional automatic focus type fixed scanner. This type of conventional rangefinder 6 is composed of a distance measuring projector 6P and a distance measuring light receiver 6R, and the distance measuring light receiver 6R is
As shown in the figure, it is composed of a plurality of light receiving elements arranged in the vertical direction, and the distance measuring projector 6P is also composed of a plurality of light emitting elements (not shown) arranged in the vertical direction. Each individual article with the bar code symbol p is placed on the conveyor and passes between the distance measuring projector 6P and the distance measuring light receiver 6R. First, the distance meter 6 can detect the height h _X of the object on the conveyor by determining which of the light receiving elements that has detected the light shielding is the highest light receiving element. Since the height H _S of the fixed scanner is known, the distance D _X between the fixed scanner and the bar code symbol p
Can be calculated by the following equation. D _X = H _S −h _X (1) The remaining operation is similar to that of FIG.

[0005]

2. Description of the Related Art The range finder 6 used in the automatic focusing type fixed scanner shown in FIG. 19 has a distance measuring projector 6P, an object T to be read, and a distance measuring light receiver 6R arranged on a straight line. Therefore, since the occupied volume becomes large, it is essentially difficult to reduce the size. Moreover, since the distance-measuring projector 6P and the distance-measuring light-receiving device 6R are essentially fixed, it is impossible to mount them on a light beam scanning type hand-held scanner.
(Furthermore, in the field of TV cameras, which differ from one industrial field to another, a focusing device that utilizes fluctuations in spatial frequency components (in detail, when focusing is achieved, the harmonics in the video signal (spatial frequency signal) are Focusing devices that utilize the phenomenon in which the wave component increases and decreases when it is out of focus are used, but the structure is complicated and large for mounting on a hand-held scanner. As described above, the movable portion in the converging optical system 3 of FIG. 18 includes the movable portion of the servo potentiometer 3P coupled to the outside of the converging lens 31 and the converging lens moving mechanism. It becomes big. Therefore, since the moving speed becomes slower by that amount, it becomes difficult to follow this when the reading distance is suddenly changed. Also, the structure is complicated,
Further miniaturization is difficult.

[0006]

SUMMARY OF THE INVENTION Therefore, the first object of the invention of this application is to accurately read optical information even when the object to be read is at a far point or a near point and the reading distance is not constant. An object is to provide an optical information reading device having an ultra-long reading depth that can be used. In other words, it is to provide an optical information reader having a very large reading range. A second object of the invention of this application is to provide a compact, lightweight and low-cost focusing device and a distance measuring device, thereby providing a compact, lightweight, and low-cost optical information reading device as a whole. To do. A third object of the invention of this application is to provide a hand-held optical information reader equipped with a compact, lightweight, and low-cost focusing device and distance measuring device.

A fourth object of the invention of this application is to prevent the resolution from rising too high at a near point and prevent it from falling too far at a far point by adding a variable diaphragm device. An object of the present invention is to provide an optical information reading device capable of maintaining the resolution at an appropriate value over a long depth. A fifth object of the invention of this application is to control the light quantity of the light source,
An object of the present invention is to provide an optical information reading device capable of maintaining the amount of received light at an appropriate value by controlling based on a distance signal and / or a scanning angle signal. A sixth object of the invention of this application is to compensate for the change in the characteristics of the entire device due to the change in the shape, size, and physical properties of the constituent members due to the change in temperature. A seventh object of the invention of this application is to use a vibrating mirror type scanning device having a scanning mirror on the front surface and a light receiving mirror on the rear surface, that is, by using the light receiving mirror on the rear surface exclusively for light reception, An object of the present invention is to provide an optical information reading device which can be made large and therefore the amount of received light can be made large.

[0008]

[Means for Achieving the Purpose] Solving the above problems,
In order to achieve the above-mentioned various objects, the optical information reading device according to the invention of the present application comprises a light source 2 for emitting a light beam for scanning an object T to be read, and an object for reading the light beam emitted from the light source 2. A focusing device 3 for focusing on T, an oscillating mirror type scanning device 4 for periodically reflecting and deflecting the light beam in a horizontal plane, and a reflected light reflected from an object to be read T by a predetermined amount. A light receiving optical system 5 for converging light at a position, a photoelectric converter 7 arranged at a subsequent stage of the light receiving optical system 5 for converting the reflected light into an electric analog signal, and connected to an output terminal of the photoelectric converter 7. The signal processing unit 8, the distance measuring device 6 for measuring the distance from the vibrating mirror type scanning device 4 to the object T to be read, and the housing 1 for accommodating all or some of these elements,
The distance measuring device 6 and the focusing device 3 are connected so that the distance signal from the distance measuring device 6 is given to the focusing device 3 as a position command signal.

The focusing device 3 includes a focusing lens 31 and
Focusing lens position detecting means 32 and focusing lens moving means 3
3 and a focusing lens position servo circuit 34.
The focusing lens position detecting means 32 does not use mechanical means such as a servo potentiometer but uses optical means such as a focusing lens position detecting position lens 32PL and a focusing lens position detecting light receiver 32PS. It was done. A variable diaphragm device 10 can be added to the focusing device 3. As the vibrating mirror type scanning device 4 described above, one in which the vibrating mirror 41 and the driving means are integrally configured can be used. The above distance measuring device 6 does not use a projector for exclusive use of distance measurement but is composed of a distance measuring light receiving lens, a distance measuring photoelectric converter, and an arithmetic circuit. The light source 2 may be provided with an automatic brightness control device for compensating the fluctuation of the received light amount due to the fluctuation of the distance between the vibrating mirror type scanning device 4 and the object T to be read. A temperature compensating device can be added to the focusing device 3, the variable aperture device 10, and the automatic light source brightness control device.

[0010]

The light beam emitted from the light source 2 is periodically reflected and deflected by the oscillating scanning mirror device 4 so that the object T to be read is repeatedly scanned. The reflected light from the object T to be read reaches the photoelectric converter 7 via the light receiving optical system 5 and is converted into an electrical analog signal. The electrical analog signal is converted into a digital signal in the signal processing section 8 and below, and the optical information is decoded. The distance measuring device 6 uses the distance measuring light receiving lens 6L, the distance measuring photoelectric converter 6S, and the distance measuring arithmetic circuit 6C, and uses only the reflected light derived from the scanning light from the object to be read T. The distance from the vibrating mirror type scanning device 4 to the object to be read T is directly measured and a distance measurement signal is output. The distance measuring device 6 is small and lightweight because it does not use a projector for exclusive use of distance measuring and the distance measuring arithmetic circuit 6C is simple.

Focusing lens position detecting means 32 of the focusing device 3
Detects the position of the focusing lens 31 during, for example, one scanning cycle of the light beam, and gives a focusing lens position detection signal to the focusing lens position servo circuit 34. The focusing lens position servo circuit 34 of the focusing device 3 is constant when the difference between the focusing lens position command signal based on the distance measurement signal from the distance measuring device 6 and the focus lens position detecting means 32 becomes zero. A desired output current is applied to the focusing lens moving means 33. The focusing lens moving means 33 of the focusing device 3 moves the focus lens 31 along the optical axis on the basis of the difference signal from the focusing lens position servo circuit 34 to focus the scanning light beam. It can be moved from the near point to the far point over an extremely long depth. The focus of the light beam is made to coincide with the object T to be read. Since the focusing device 3 does not use mechanical means such as a servo potentiometer, it is small and lightweight.

The variable diaphragm device 10 makes the aperture diameter of the variable diaphragm I relatively small when the object T to be read is at a near point (thus, when the focusing lens is focused on the near point). , By relatively reducing ω _d of the light beam diameter 2 at the time of emission from the variable diaphragm, the beam waist diameter at the near point is relatively thickened, and the beam diameter 2ω _ZC before and after the near point.
To prevent sudden changes in. As a result, the variable diaphragm device 10 causes the beam waist diameter 2ω _OC when the light beam is focused on the near point to be too thin and the beam diameter 2ω before and after the near point.
It is possible to prevent a rapid increase in _ZC and prevent a decrease in S / N ratio. In addition, the variable diaphragm device 10 is provided with an object T to be read.
Is at a far point (hence, when the focusing lens is focused at the far point), the aperture diameter of the variable diaphragm I is relatively increased, and the light beam diameter 2ω _d at the time of emission from the variable diaphragm is set relatively. Beam waist diameter at the far point 2
Make ω _OF relatively small. As a result, the variable diaphragm device 10 prevents the beam waist diameter 2ω _OF from becoming too thick when the light beam is focused on the far point, and thus the S / N ratio is increased.
It is possible to prevent the ratio from decreasing.

[0013]

【Example】

(First Embodiment) A first embodiment of the optical information reader according to the invention of this application will be described. First, the overall configuration will be generally described. FIG. 1 is a diagram showing the overall configuration of a first embodiment of the invention of this application. In FIG. 1, 2 is a light source (for example, laser diode), 2D is a light source drive circuit, 3 is a focusing device, 4 is a vibrating mirror type scanning device, 5 is a light receiving optical system, 6 is a distance measuring device, and 7 is a photoelectric converter. (Light receiver), 8 is a signal processing unit, 9 is a centralized control device (for example, a microprocessor unit), TS is a temperature sensor,
T is an object to be read. The description of the housing 1 is omitted.

In summary, the light emitted from the light source 2 is focused by the focusing device 3, the first mirror (scanning mirror) 41 _{1 of} the vibrating mirror type scanning device 4, the object T to be read, and the light receiving optical system. 5
Focusing / deflecting means 5CP and vibrating mirror type scanning device 4
Via a second mirror (receiving mirror) 41 _2, a photoelectric converter so as to reach the (receiver) 7 are arranged.
The signal processing unit 8 is provided at the output terminal of the photoelectric converter (light receiver) 7.
Is connected. The distance measuring light receiving lens 6L of the distance measuring device 6 is
From the scanning mirror 41 ₁ of the oscillating mirror type scanner 4 in the transverse direction by a distance d is disposed spaced positions. Distance measuring device 6
Measures the distance between the scanning mirror 41 ₁ and the reading object T (or the distance between the object to be read object T and ranging light lenses 6L), and outputs a distance signal DS. The focusing device 3 moves the focusing lens 31 in the optical axis direction on the basis of the distance signal DS, and thus changes the distance between the light source 2 and the focusing lens 31 so that the focus is on the object T to be read. Match. During this time,
The temperature characteristics of the entire system are compensated based on the output signal of the temperature sensor TS. The brightness of the light source 2 is controlled based on the output of the photoelectric converter 7 (or the distance measuring photoelectric converter 6S) or based on the scanning angle signal. Thus,
The bar code symbol p on the object T to be read is read.

Next, the partial structure and partial operation of the first embodiment will be described. (Focusing Device of First Embodiment) FIG. 2 is a diagram showing the operating principle of the focusing device 3 used in the first embodiment, and FIG. It is a figure which shows the optical focusing unit 3U which comprises a part. In FIG. 2, 31 is a focusing lens, 3H is a cylindrical focusing lens holder, 32 is a focusing lens position detecting means, 33 is a focusing lens moving means, 34 is a focusing lens position servo circuit (error amplifier), Reference numeral 35 is an electronic voltage divider. The focusing lens 31 is made of a transparent material such as glass or synthetic resin. Focusing lens position detecting means 32
Includes a focusing lens position detecting position lens 32PL, a focusing lens position detecting photoelectric converter 32PS, and a focusing lens position calculating circuit 32PC.

The cylindrical focusing lens holder 3H has a side wall of light penetrating the peripheral wall thereof in a slightly oblique direction as shown in the drawing (ie, a direction slightly inclined forward from the radial direction (radial direction)). A side path of light passing therethrough is formed, and the focusing lens position detecting position lens 32PL is embedded therein. Focusing lens position detection position lens 32P
A focusing lens position detecting photoelectric converter 32PS is disposed at a light condensing point by L, and a focusing lens position calculating circuit 32P is provided at an output terminal of the focusing lens position detecting photoelectric converter 32PS.
C is connected. Focusing lens position detection photoelectric converter 32
The output of PS, that is, the output of the focusing lens position detecting means 32 becomes a focusing lens position detection signal. The magnitude of the focus lens position detection signal is a function of the position of the focus lens holder 3H, and thus also the position of the focus lens 31.

The focusing lens moving means 33 comprises a movable coil drive circuit 33CD, a movable coil 33C and the like. The movable line wheel 33C is connected to the focusing lens holder 3H. The focusing lens position servo circuit (error amplifier) 34 is configured by using, for example, an operational amplifier, and outputs a constant desired output in a state where the combined voltage of the input voltage to the + terminal and the feedback voltage to the − terminal is substantially zero. It becomes an electric current. Focusing lens position servo circuit 34 +
A focusing lens position command signal is given to the terminal directly from the distance measuring device 6 or via a centralized control device (for example, a microprocessor unit) 9. In addition, a focusing lens position detection signal is given to the-terminal from the focusing lens position detection photoelectric converter 32PS via the focusing lens position calculation circuit 32PC. (The electronic voltage divider 35 will be described later.) The output (current) of the focusing lens position servo circuit 34 is given to the movable coil drive circuit 33CD, and the movable coil drive circuit 3 is driven.
The output (current) of 3CD is given to the movable coil 33C. When the signal of the difference between the focus lens position command signal and the focus lens position detection signal becomes zero, the movable coil wheel 33C stops (stops).

FIG. 3A is a vertical sectional view of an optical focusing unit 3U which is a main part of the focusing device 3 used in the first embodiment, and FIG. 3B is used for this. Support spring 3S
A front view of P and the same figure (c) are operation principle diagrams of the photodetector for detecting the focusing lens position. In FIG. 3A, 2 is a light source (for example, a laser), 31 is a focusing lens, 3H is a focusing lens holder, 3SP and 3SP are a pair of support springs, 3B is a lens barrel (barrel), and 32PL is focusing. Position lens for lens position detection, 32PS is a photodetector for focus lens position detection,
33C is a movable coil, 33M is a permanent magnet, and 33Y is a yoke.

The focusing lens 31 is held by a focusing lens holder 3H, the focusing lens holder 3H is supported and pinched by a pair of support springs 3SP and 3SP, and both support springs 3SP and 3SP are, for example, a lens barrel 3B. Each of them is fixed by a step provided on the inner peripheral wall of the. The focusing lens holder 3H and the pair of support springs 3SP and 3SP work together to
The focusing lens support means 39 is configured. Support spring 3SP
Is composed of an outer ring, an inner ring, and several connecting portions (for example, three connecting portions) that connect both rings, as shown in FIG. 3B. The spring action of the support spring 3SP is carried by, for example, three connecting portions. An appropriate length is given to each connecting portion according to the required spring force. The focusing lens holder 3H includes a pair of support springs 3SP,
Since it is sandwiched by 3SP, it can be moved only in the optical axis direction. Therefore, the focusing lens 31 can also be completely moved only in the optical axis direction.

The ring-shaped movable line wheel 33C is connected in series to the light source side of the focusing lens holder 3H. Among the above-mentioned elements, the focusing lens 31, the focusing lens holder 3H, the focusing lens position detecting position lens 32PL, and the movable coil 33C jointly constitute a movable portion. An annular permanent magnet 33M is coaxially arranged on the outer side of the movable coil 33C, and a substantially annular or perforated plate-like shape (hereinafter, simply referred to as “annular”) on the outer side of the annular permanent magnet 33M. No Yoke 3
3Y is provided. The substantially annular yoke 33Y is fixed to the inner peripheral wall of the lens barrel 3B.

The annular permanent magnet 33M is magnetized, for example, in the radial direction (radial direction). Since the yoke 33Y is made of iron or other ferromagnetic material, it efficiently guides the magnetic flux of the permanent magnet 33M to the movable coil 33C of the movable portion. Movable line 33C
Receives a positive or negative force in the axial direction by energization. The force received is proportional to the product of the magnitude of the drive current and the magnitude of the magnetic field that intersects the drive current. Therefore, the movable wire 33
C moves forward or backward in the axial direction. That is, the movable line 3
When a drive current is supplied to 3C, the focusing lens 31
Will move forward or backward in the axial direction depending on whether the drive current is positive or negative.

Focusing lens position detecting position lens 3
The 2PL is embedded in the peripheral wall of the focusing lens holder 3H forming a part of the movable portion. The position of the inner surface of the focusing lens position detection position lens 32PL is closer to the light source than the focusing lens 31, and its optical axis is, as shown in the drawing, more than the radial direction (radial direction) of the focusing lens holder 3H. It is tilted slightly forward. (However, the presence or absence of inclination is not an essential matter.) The peripheral wall portion of the lens barrel 3B, which intersects the optical axis of the focusing lens position detection position lens 32PL (extension line thereof), is penetrated as shown in the figure. A hole is bored, and a focusing lens position detecting photoelectric converter 32PS is arranged near the outer peripheral wall of the lens barrel 3B.

The cross-sectional shape of the through hole of the lens barrel 3B and the light-receiving surface shape of the focusing lens position detecting photoelectric converter 32PS are both vertically long, and their longitudinal dimension is the focusing lens position detecting position. It should be large enough to completely cover the range of movement of the lens 32PL. (However, the focusing lens position detection photoelectric converter 32P
S is the position lens 32PL for focusing lens position detection
Does not need to be parallel to the moving direction (direction of the optical axis of the focusing lens 31). The laser light (side light) that has reached the inner surface of the focusing lens position detecting position lens 32PL is guided to the outside of the focusing lens holder 3H, like the focusing lens position detecting laser light 3LL in FIG. , Focusing lens position detection light receiver 3
It is made incident on the light receiving surface of 2PS. The focusing lens position detecting position lens 32PL is designed such that the focal point of the laser light 3LL coincides with the light receiving surface of the focusing lens position detecting photoelectric converter 32PS.

Among the above-mentioned elements, the lens barrel 3B, the focusing lens position detection light receiver 32PS, the permanent magnet 33M, and the yoke (yoke) 33Y jointly constitute a fixed portion.
Then, the fixed part, the movable part, and the support spring 3SP together form an optical focusing unit 3U. In this embodiment, the light source 2 is arranged inside the lens barrel 3B and in the inner space of the movable ring 33C, and is supported by a yoke 33Y, as shown in the figure. This reduces the axial dimension.

The position of the focusing lens 31 and the focusing lens 31
The functional relationship with the light condensing position due to is described. FIG. 14 is a diagram showing a light focusing position of the focusing lens 31. When the focusing lens 31 having the focal length f ₀ is placed at the position of the distance f ₀ from the light source 2 as shown in the figure, the light emitted from the focusing lens 31 becomes parallel light. Therefore, this position can be set as a reference position for the focusing lens 31. Alternatively, the x-axis can be set according to the optical axis direction of the focusing lens 31, and this position can be the origin (x = 0). When the focusing lens 31 moves away from the reference position (x = 0) to the side opposite to the light source (the object T side to be read) by Δf, the laser light is focused from the focusing lens to the position f ₂ (x = f ₂ ). .

If f ₀ + Δf = f ₁ is set for easy viewing, the above relationship is well known as the lens formula (1 / f ₀ ) = (1 / f ₁ ) + (1 / f ₂ ). ing. By modifying the above equation, the following equation is obtained. f ₂ = (1 / Δf) f ₀ ² + f ₀ (2) That is, f ₂ is proportional to (1 / Δf). Focusing lens 31
When the internal optical path length from the distance measurement origin to the distance measurement origin is L and the distance from the distance measurement origin to the barcode is D _x , f ₂ is given by the following equation. f ₂ = D _x + L (3) From the equations (2) and (3), the following equation is obtained. Δf = f ₀ ² / (f ₂ −f ₀ ) = f ₀ ² / (D _x + L−f ₀ ) (4) Δf in the formula (4) is a focusing lens position command signal based on the distance signal D _x. I can understand. Hereinafter, such Δf will be referred to as Δf _c .

Focusing lens position detecting photoelectric converter 32PS
The focusing lens position control circuit 34 will be described. FIG. 15 is a side view of the focusing lens position detecting photoelectric converter 32PS and a block diagram of the focusing lens position control circuit 34. In FIG. 15, reference numeral 32PS designates a focusing lens position detecting photoelectric converter, 34 designates a focusing lens position control circuit, and 33C.
Is a movable wheel, 33CD is a movable wheel drive circuit, and 9 is a centralized control device (for example, a microprocessor unit).
The operation characteristics of the focusing lens position detecting photoelectric converter 32PS are as follows. When the spot light arrives at the light receiving surface of the focusing lens position detecting photoelectric converter 32PS,
A current I _a is generated at the A end and _a current I _b is generated at the B end. Current I
The size of _a and I _b will vary depending on the position where the spot light strikes. Focusing lens position detection photoelectric converter 32PS
The x'axis is taken along the longitudinal direction of the and the A end is the origin (x '=
0), B end is x '= W, and the intensity of the spot light is constant for simplicity, the magnitudes of the currents I _a and I _b are as follows. I _a = p (W−x ′), I _b = px ′ (5) where p is a proportional constant.

Focusing lens position detecting photoelectric converter 32PS
3 is fixed to the lens barrel 3B of the optical focusing unit 3U as shown in FIG. 3A, it does not move. On the other hand, the focusing lens position detecting position lens 32PL
Is connected to the movable portion (for example, the movable line 33C) of the optical focusing unit 3U as described above, and therefore moves as the focusing lens 31 moves. As shown in FIG. 3A, the focusing lens position detecting position lens 32PL takes in unnecessary light of the laser light source 2 (side light that does not enter the focusing lens 31) and condenses the focused lens position. The detection laser light 3LL is formed. The spot (or striation) is
The light is applied to the light receiving surface of the focusing lens position detecting photoelectric converter 32PS. Thus, the light spot (or striation) condensed by the focusing lens position detecting position lens 32PL
Moves on the focusing lens position detecting photoelectric converter 32PS as the focusing lens 31 moves. Focusing lens 31
Is Δf, and the moving distance of the light spot (or striation) is Δ
If f ′, the following equation is approximately established. Δf ′ = aΔf (6) where a is a proportional constant. The above-mentioned proportionality constant a is shown in FIG.
As is clear from the above, the value is close to 1.

Now, when Δf = 0 (hence x = 0),
Let x '= g. That is, the focusing lens 31 moves to the reference position (x
= 0), the light spot of the focusing lens position detecting laser beam 3LL focused by the focusing lens position detecting position lens 32PL strikes the focusing lens position detecting photoelectric converter 32PS (position (position)). ), X '= g.
Then, when x = Δf, x ′ = g + Δf ′. That is, the focusing lens 31 moves from the reference position by Δf to the object T to be read.
When moving to the side, the point (position) at which the light point of the focusing lens position detecting laser beam 3LL focused by the focusing lens position detecting position lens 32PL strikes the focusing lens position detecting photoelectric converter 32PS. Is x ′ = g + Δf ′ as shown in FIG. Then, equation (5),
The following equation is obtained based on (6). I _b / (I _a + I _b ) = x ′ / W = (Δf ′ + g) / W = (aΔf + g) / W (7) where W is the total light receiving width of the focusing lens position detecting photoelectric converter 32PS. This equation holds even if the amount of incident light changes.

By modifying the equation (7), the following equation is obtained. Δf = [{WI _b / (I _a + I _b )}-g] / a (8) Δf according to the equation (8) is a focusing lens position measurement signal. In this case, Δf will be referred to as Δf _m . In principle, the focusing lens position command signal Δf _c according to equation (4)
It is possible to apply the focusing lens position measurement signal Δf _m according to Expression (8) to each input terminal of the differential amplifier (error amplifier) in the focusing lens position servo circuit 34 of FIG. 2. When the focusing operation starts, Δf increases, and therefore Δf
_{Although m} increases, the focusing lens 31 stops when Δf _m matches Δf _c . Then, the focusing operation ends.

Returning to FIG. 15, the electronic voltage divider 35 and the error amplifier E (that is, the focusing lens position servo circuit 34) will be described. The current signal I _a from the A terminal and the current signal I _b from the B terminal are respectively converted into voltage signals, and V
_a and V _b . The voltage signal V _a from the A terminal is applied to the adder A, and the voltage signal V _b from the B terminal is applied to the adder A and − of the error amplifier E. The adder A produces the sum signal V _a + V _b . The sum signal V _a + V _b is applied to the first input terminal of the electronic voltage divider VD. Equation (7) is
It is rewritten as follows using the voltage signals V _a , V _{b and} V _a + V _b . V _b / (V _a + V _b ) = (aΔf _c + g) / W (9) V _b = (V _a + V _b ) (aΔf _c + g) / W (10) In the expression (10), the incident light amount changes. Is also true. The central control unit (e.g. microprocessor unit) 9 sends the voltage division control signal DCS to the second input terminal of the electronic voltage divider VD. The voltage division ratio by the voltage division control signal DCS is (aΔ
f _c + g) / W. The electronic voltage divider VD has a sum signal V
_The value obtained by multiplying _a + V _b by the voltage division ratio (aΔf _c + g) / W is output.

The output of the electronic voltage divider VD and the actual _Vb are compared with the error amplifier E (that is, the focusing lens position servo circuit 3).
4), and the output is applied to the movable coil wheel 33C.
When the focusing operation starts, Δf ′ increases as Δf increases, and thus the actual V _b increases, but V _b becomes (V _a
+ V _b ) (aΔf _c + g) / W, the focusing lens 31 stops. Then, the focusing operation ends. Thus, the focusing lens 31 is moved to the position (x = Δf) instructed by the central control unit (for example, the microprocessor unit) 9.
_It can be held in _c ). The focusing operation based on equations (4) and (8) (see FIG. 2) and the focusing operation based on equation (10) (FIG. 15) are essentially equivalent. However, the latter requires less number of calculations. Electronic voltage divider VD of FIG.
Include digital-to-analog converter A / D and E ² PO
You can use T (psychone). A dedicated light source for focus lens position detection is not required.

(Distance Measuring Device of First Embodiment) The first distance measuring device used in the first embodiment will be described. FIG.
It is a principle explanatory drawing of the 1st range finder used for the example. In FIG. 4A, 2 is a light source, 41 is a vibrating mirror, T is an object to be read, 6 L is a distance measuring light receiving lens, 6 s is a small-diameter distance measuring photoelectric conversion element, and a is a scanning center of the vibrating mirror 41. A line (that is, a center line in the reading direction), b ₂ is a light receiving center line of the distance measuring light receiving lens 6L. A projection light source dedicated to distance measurement is not required.

For convenience of explanation, the distance between the scanning center line a ₁ and the light receiving center line b ₂ is e, the distance between the vibrating mirror 41 and the object T to be read (or the distance measuring light receiving lens 6L). (Distance between the object to be read T) D _x , the scanning center line a ₁ and the object to be read T
Is A, the intersection of the light receiving center line b ₂ and the object T to be read is B, the reflected light beam from the point A to the distance measuring light receiving lens 6L is a ₂ , and the light beam from the vibrating mirror 41 to the point B is b. _1. Angle of line segment AB from the center point of oscillating mirror 41 (angle between scanning center line a ₁ and ray b ₁ toward point B = swing angle)
Be θ. For simplicity, the scanning center line a ₁ and the object to be read T
Are orthogonal to each other (that is, the reading center line a ₁ and the object T to be read are orthogonal to each other). Since the value of e is given, if the swing angle θ can be measured, the distance D _X to the object T to be read is given by the following equation. D _X = e / tan θ (11)

Since the distance-measuring photoelectric conversion element 6s has a small diameter, a light ray arriving outside the light-receiving center line b ₂ (for example, the light ray a ₂ arriving from the point A) has the distance-measuring photoelectric conversion element as shown in the figure. It will be removed from the conversion element 6s and will not be received. Therefore, the light rays received by the distance measuring photoelectric conversion element 6s are only the light rays that arrive along the light receiving center line b ₂ .
The time t _A at which the scanning beam passes the point _A can be determined based on the scanning synchronization signal. Scanning beam is point B
Since the time point t _B at which the output of the distance measuring photoelectric conversion element 6s reaches its maximum, it can be detected by detecting the output maximum time. Well-known means are used for detecting the maximum output time.

Assuming that the time difference between the time points t _A and t _B is t _d , the angle (swing angle) θ at which the line segment AB is seen from the center point of the vibrating mirror 41 is proportional to the time difference t _d . That is, θ = kt _d (12) where k is a proportional constant determined by the scanning speed. Therefore,
The distance D _x to the object to be read T is given by the following equation. D _X = e / tan (kt _d ) = e cot (kt _d ) (13) FIG. 4 (b) shows the object T to be read in FIG.
Shown is the case of rotating counterclockwise by an angle ψ with respect to. The broken line T'indicates the current position of the object to be read after rotation. The rotation of the angle ψ causes an error D _X ′. D _X ′ is given by the following equation. D _X ′ = e tan ψ (14) If the angle ψ (radian) is minute, D _X ′ ≈e ψ≈0
Therefore, there is no fear (fear) of impairing the focus adjustment.

(Vibration mirror type scanning device of the first embodiment)
The vibrating mirror type scanning device 4 used in the first embodiment will be described. 6A and 6B are a horizontal sectional view and a vertical sectional view of the same oscillating mirror type scanning device. Figure 6
In (a) and (b), 41 ₁ is a first reflecting mirror (scanning mirror), 41 ₂ is a second reflecting mirror (light receiving mirror), 42 is a movable part, 46 is a holder, and 47 is a fixed joint. Iron (yoke) 49 is a drive winding. The movable part 42 is
The movable part main body includes the movable part main body and the rotating shaft 425.
Two movable magnets 42, which are plate-shaped, rod-shaped, or three-dimensional
1, 421 and a movable yoke 422. The first reflection mirror 41 ₁ , the movable part main body, and the second reflection mirror 41 ₂
And are integrally configured.

When the drive winding 49 is not energized, the movable body stands still at the position shown. When the movable body is rotated by an appropriate angle from the stationary position and released, an attractive force (magnetic spring force) is generated between the movable magnet 421 and the yoke 47, so that the movable body 42 starts free reciprocating vibration. . When the drive winding 49 is energized, the drive current intersects the magnetic field of the movable magnet 421, so that a positive or negative couple acts on the movable magnet 421. As a result, the movable body 42 starts forced vibration. First
Reflecting mirrors 41 ₁ of the light beam coming from the focusing device 2, it is periodically reflected and deflected. Second reflection mirror 41
_2, the reflected light coming through the light collecting and deflecting means 5CP from flying spot on the reading object T (moving point of light), and periodically to reflect deflected towards the photoelectric converter 7 injection To do. The condenser / deflector 5CP may have a condenser lens and a reflection prism integrally formed as shown in the figure, or may have the condenser lens and the reflection prism separated from each other. (Note that, regarding the above-mentioned vibrating mirror type scanning device 4,
It is described in detail in the specification and drawings of Japanese Patent Application No. 6-87157 filed by the applicant of the present invention. )

(Light receiving optical system of the first embodiment) The light receiving optical system 5 used in the first embodiment will be described. Returning to FIG. 1, 5CP is a light collecting and deflecting means that has both light collecting and deflecting functions. Condensing and deflecting means 5
The CP and the second reflecting mirror 42 ₂ (see FIG. 6A) jointly form the light receiving optical system 5. The condensing / deflecting means 5CP condenses the reflected light coming from the flying point (light moving point) on the object T to be read, converts the traveling direction of the condensed reflected light, and performs the second reflection. to emitted toward the mirror 41 _2. The second reflecting mirror 41 _2, the incoming reflected light,
The light is periodically reflected and deflected and is incident on the photoelectric converter 7.
In this embodiment, the amount of received light can be increased by enlarging the light receiving aperture of the condenser / deflector 5CP.

(Light Source of First Embodiment) In FIG. 1, 2
Is a light source. As the light source 2, for example, a visible light semiconductor laser that emits a visible light beam, or a surface emitting type LED using a mesa structure with an extremely small diameter is used. A condenser lens can be incorporated in the light source 2. However,
The condenser lens must preserve the side light.

(Light Source Driving Circuit of First Embodiment) The light source driving circuit of the first embodiment will be described. Since the light emitted from the light source 2 is a beam-like light beam, the light power incident on the bar code does not change even if the distance between the bar code and the scanning device changes. The reflected light from the barcode surface incident on the light receiving lens changes depending on the distance, and when the light receiving aperture is constant, the amount of received light is inversely proportional to the square of the distance from the barcode. By controlling the projected light output based on the distance data obtained by distance measurement, the received light amount can be kept constant even if the distance from the bar code changes. (However, the maximum output power may be limited by the optical radiation safety standards, etc.)

FIG. 17 is a block diagram of the light source drive circuit 2D. This figure shows the case where a laser diode is used as the light source. A part of the light emitted from the laser diode LD is a monitoring photodiode MP for observing the optical output.
It is incident on D. The monitor photodiode MPD generates a monitor current proportional to the light emission output of the laser diode LD. The monitor current is converted into a voltage signal EC by the resistor R and input to the-terminal of the error amplifier E. The light output control voltage LPCS is input to the + terminal of the error amplifier E. The monitor voltage EC is compared with the light output control voltage LPCS by the error amplifier E, and the light emission output of the laser is controlled so as to have the same voltage. Light output control voltage LP
The CS is, for example, an optical output control signal (logical value) sent from a centralized control device (for example, a microprocessor unit) 9 converted into an analog amount by a DA converter D / A.

(Temperature Compensation Device of First Embodiment) In FIG. 1, TS is a temperature sensor. The temperature measurement signal of the temperature sensor TS can be used to perform temperature compensation of the focusing device 3 and the light source drive circuit 2D. As the temperature sensor TS, a temperature sensitive element having a known temperature characteristic (for example, a thermistor or a diode) can be used. Since the thermistor is an element whose resistance value changes with temperature, the resistance value is converted into a voltage value by a resistance-voltage conversion circuit, and the voltage value is converted to A
The signal is converted into a digital signal by the / D converter and then input to the centralized control device (eg, microprocessor unit) 9. For example, a signal proportional to the temperature measurement signal can be added (subtracted) to the focusing lens position servo circuit 34 of the focusing device 3. This makes it possible to prevent the focus from fluctuating due to temperature fluctuations. As a result, a plastic lens can be used as the focusing lens. Further, for example, another signal proportional to the temperature measurement signal can be added (subtracted) to the light source drive circuit 2D. This eliminates the influence of temperature fluctuations on the amount of received light.

(Second Embodiment) A second embodiment of the optical information reading device according to the invention of this application will be described. The second embodiment corresponds to the first embodiment to which a variable diaphragm device is added. FIG. 7A is a principle diagram of the operation of the first variable diaphragm device used in the second embodiment. FIG. 7 (a)
2 is a light source, 31 is a focusing lens, I ₁ is a variable circular diaphragm, and IC is a diaphragm control circuit. The variable circular aperture I ₁ , the aperture control circuit IC, and a circular aperture drive mechanism (not shown) cooperate to form a first variable aperture device 10. The structures and functions of the variable circular diaphragm I ₁ and the circular diaphragm driving mechanism are similar to those known in the field of cameras, for example. The shape of the aperture (aperture) of the variable circular diaphragm I ₁ does not change even if the aperture diameter changes, and is always circular.
The aperture control circuit IC receives the distance signal from the distance measuring device 6 directly or via the microprocessor 9, converts it into an aperture control signal, and applies it to the circular aperture drive mechanism. The circular diaphragm driving mechanism, based on the diaphragm control signal, controls the variable circular diaphragm I.
Adjust the opening diameter of ₁ . Variable circular aperture I after rotation adjustment
₁ of the opening diameter is a linear function of the distance signal.

FIG. 7 (b) is a diagram showing the operating principle of the second variable diaphragm device used in the second embodiment. In FIG. 7B, 2 is a light source, 31 is a focusing lens, I ₂ is a variable parallelogram diaphragm, and IC is a variable parallelogram diaphragm control circuit.
Variable parallelogram diaphragm I ₂ and diaphragm control circuit IC
And a parallelogram diaphragm driving mechanism (not shown) constitute the second variable diaphragm device 10. The structures and functions of the variable parallelogram diaphragm I ₂ and the parallelogram diaphragm driving mechanism are similar to those known in the field of cameras, for example. Only the lateral width (short side length) of the aperture of the variable parallelogram diaphragm I ₂ changes. The aperture control circuit IC receives the distance signal from the distance measuring device 6 directly or via the microprocessor 9, converts it into an aperture command signal, and applies it to the parallelogram aperture drive mechanism. The parallelogram diaphragm driving mechanism adjusts only the lateral width (short side length) of the opening of the variable parallelogram diaphragm I ₂ based on the diaphragm command signal. The aperture diameter of the variable circular diaphragm I ₂ after the rotation adjustment is a linear function of the distance signal.

The usefulness of the variable diaphragm device will be described in more detail. FIG. 9 is a vertical cross-sectional view of the laser beam after passing through the focusing lens. However, the laser light has a Gaussian distribution. In FIG. 9, 31 is a focusing lens, ω _d is the radius of the laser beam at the exit point of the focusing lens 31 (= radius of the focusing lens), ω _O is the beam waist radius, and Z _O is the focusing lens 31. Is the distance from the exit point to the beam waist position. At this time, the beam waist radius ω _O and the diameter 2ω _O are expressed by the following equations. _{ω O = λZ O / (πω} d) (15) 2ω o = 2λZ O / (πω d) (15 ') However, λ is the wavelength of the laser light.

Assuming that the laser beam has a constant radius ω _d and a wavelength λ at the exit point of the focusing lens 31, the beam waist radius ω _o (and diameter 2ω _O ) is
It is a linear function of the beam waist distance Z _O. Expression (1
If 5 ') is made into a graph, it becomes like the straight line 1 of FIG. However, in FIG. 10, for convenience, because are described three coordinate system, the curve 1, the distance Z _O of the horizontal axis, the coordinate system to a longitudinal axis of the beam waist diameter 2ω _O (Z _O -2ω _O Note that it is a straight line on the coordinate system. As is clear from the straight line 1 in FIG. 10, the beam waist position is the far point Z.
When it is in _OF , beam waist diameter 2ω _OF is thick,
When the beam waist position is at the near point Z _OC , the beam diameter 2ω _OC is thin.

The beam waist radius ω _O is determined by selection of the wavelength λ of the laser light source, the lens aperture (2ω _d ), and the beam waist position Z _O , as is apparent from the equation (8). Generally, when a predetermined far point Z _OF is automatically focused,
Ω _d is selected so that the beam waist radius ω _O has a desired value ω _OF . Then, when the focal point Z _OC is automatically focused, the beam waist diameter 2ω _OC ends up being much smaller (thinner) than the desired beam waist diameter, as is clear from the straight line 1 in FIG. That is, (Z _OF
/ Z _OC ) and end. As a result, near point Z _OC
If the optical resolution in (1) is excessively increased, even soys other than the read data (paper stains, uneven printing, etc.) may be detected and the signal S / N may be deteriorated.

However, in the second embodiment, since the variable diaphragm I is arranged in front of or behind the focusing lens 31, as shown in FIG. 7, the focusing lens 31 is focused on the near point Z _OC . When adjusting, the variable diaphragm I is automatically adjusted in parallel,
By reducing _d , the beam waist radius ω
By increasing the _OC , it is possible to prevent the above deterioration of the S / N ratio. Figure 11 is a variable throttle is a graph showing the waist position and diameter of the laser beam after passing through the minimum value of the curve 2 of the drawing, i.e. the focusing lens 31 near point Z _OC
It can be seen that the beam waist diameter 2ω _OC when focused on is much larger (thicker) than that of the curve 2 in FIG. 10 and is close to the desired value (request value) 2ω _OF .

Returning to FIG. 9, ω _Z is the radius of the laser beam at a point Z away from the beam waist position. The radius ω _Z and the diameter 2ω _Z of the above laser beam are
It is given by the following formula. ω _Z ² = ω _O ² {1+ (λ / (πω _O ² )) ² Z ² } (16) (2ω _Z ) ² = 4ω _O ² {1+ (λ / (πω _O ² )) ² Z ² } ( 16 ') When the beam waist is located at an arbitrary near point Z _OC , a graph of the equation (9') is as shown by the curve 2 in FIG. As described above, three coordinate systems are described in FIG. 10 for convenience. In the curve 2, the near point Z _OC is the origin, the distance Z from the near point Z _OC is the horizontal axis, and the laser beam A coordinate system with the diameter 2ω _Z as the vertical axis (that is, Z-2
ω _Z coordinate system).

Further, when the beam waist is located at an arbitrary far point Z _OF , the graph of the equation (16 ') is as shown by the curve 3 in FIG. The curve 3 is a straight line on the coordinate system (that is, Z-2ω _Z coordinate system) having the far point Z _OF as the origin, the distance Z from the far point Z _OF as the horizontal axis, and the laser beam diameter 2ω _Z as the vertical axis. is there. (Furthermore, when it is desired to express the diameter 2ω _{Z of the} laser beam as a function of the spatial coordinate z with the emission point of the focusing lens 31 as the origin, Equation (1
For example, the following equation may be substituted for 6 '). (When the beam waist is at the near point Z _OC ) Z = z−Z _OC (17) (When the beam waist is at the far point Z _OF ) Z = z−Z _OF (17 ′) where z = 0 (origin ) Is the exit point of the focusing lens 31, z =
Z _OC is a near point and z = Z _OF is a far point. )

As is clear from the curve 2 in FIG. 10, when the focusing lens is automatically focused on the near point Z _OC , the beam diameter is 2ω.
_{Since Z} rapidly increases (becomes thicker) before and after the near point Z _OC , it is necessary to improve the accuracy of automatic focus control. However, the distance from the focusing lens 31 to the object to be read z (Z _OC
+ Z) changes with a fast cycle as the scanning beam is deflected, and also with a fast cycle when the surface of the object to be read is curved, it is difficult to make the automatic focus control operation follow such a change. Is. Therefore, the optical resolution is likely to change.

However, in the second embodiment, as described above, as shown in FIG.
Since the variable diaphragm I is provided, the focusing lens 31 is moved to the near point Z.
When focusing on _OC , the variable aperture I is also automatically adjusted in parallel, and the beam waist radius ω _OC is relatively increased (thickened) by reducing ω _d. Therefore, equation (9) and The coefficient (λ / (πω _OC ² )) ² of the variable Z ² in each curly bracket {} on the right side of (9 ′) becomes small, so that the change of ω Z ² before and after the near point Z _OC becomes slow, The change (rise) of the beam radius ω _Z also becomes slow. According to FIG. 11, it can be seen that the curvature of the curve 2 is much smaller than that of the curve 2 of FIG. In short, the second embodiment avoids a situation in which the beam waist diameter at the near point becomes too thin with the use of the automatic focusing device, and the optical path length caused by the beam scanning or the curvature of the surface of the object to be read is reduced. It is possible to reduce the change in the optical resolution due to the change. The other matters of the second embodiment are the same as those of the first embodiment.

(Third Embodiment) A third embodiment of the optical information reader according to the invention of this application will be described. The third embodiment corresponds to the one in which the focusing device in the first embodiment is replaced with the following one and the following variable diaphragm device is added. FIG. 8 is an operation principle diagram of the focusing device 3 and the variable diaphragm device used in the third embodiment. In FIG. 8, 2 is a light source, 3H is a cylindrical focusing lens holder, FS is a feed screw, g ₁ is a first gear, g ₂ is a second gear, M is an electric motor, and 33 is a focusing lens position movement. Means, I ₃ is a rotatable rectangular diaphragm, and MC is a focusing lens position control circuit and rectangular diaphragm rotation angle control circuit.

The feed screw FS is formed as a male screw on the outer peripheral surface of the cylindrical focusing lens holder 3H, and is screwed to a female screw formed on the inner peripheral surface of the lens barrel 3B (not shown). (Or,
By reversing this relationship, a female screw may be formed on the focusing lens holder 3H side and a male screw may be formed on the lens barrel 3B side. ) Both screws together form the feed mechanism FM.
The first gear g ₁ is fast-coupled to the electric motor M via a rotary shaft, and the second gear g ₂ is a cylindrical focusing lens holder 3H.
Is coaxially coupled to one end surface (or outer peripheral surface) of the.
The second gear g ₂ is provided with a through hole for passing the light beam. The two gears g ₁ and g ₂ together form a gear mechanism (g ₁ and g ₂ ). (The second gear g ₂ and the cylindrical focusing lens holder 3H can be formed integrally or separately.)

The feed screw mechanism FM and the gear mechanism (g ₁ , g
₂ ), the electric motor M, and the focusing lens position control circuit / rectangle diaphragm rotation angle control circuit MC jointly configure the focusing lens position moving means 33. The focusing lens position control circuit / rectangle diaphragm rotation angle control circuit MC receives the distance signal from the distance measuring device 6 directly or via the microprocessor 9, and determines the focusing lens position command signal / rectangle diaphragm rotation angle. It is converted into a command signal and applied to the electric motor M. The focusing lens position control command signal and the rectangular aperture rotation angle control signal are linear functions of the distance signal. The electric motor M rotates according to the focusing lens position control signal. The rotational movement of the electric motor M is transmitted to the cylindrical focusing lens holder 3H via the gear mechanism (g ₁ , g ₂ ) and converted into a linear movement in the axial direction by the feed mechanism FM. Focusing lens 3 after movement adjustment
The position of 1 is a linear function of the distance signal. (The tooth ratio of the gear mechanism (g ₁ , g ₂ ) and the pitch of the feed screw FS are reflected in the proportional coefficient of the distance signal.)

The rotatable rectangular diaphragm I ₃ is composed of a rotatable plate body and has a rectangular opening in the center thereof. The rotatable rectangular diaphragm I ₃ includes the second gear g ₂ or the focusing lens holder 3
Combined concentrically with H. (The three are constructed as one body or separate bodies). The rotatable rectangular diaphragm I ₃ , the gear mechanism (g ₁ , g ₂ ), the electric motor M, and the focusing lens position control circuit / rectangular diaphragm rotation angle control circuit MC jointly rotate. The rectangular diaphragm device 10 is configured. Since the semiconductor light beams from the laser light source is a cross-sectional shape based on the original portrait, the cross-sectional geometry of the incident light beam to the rotatable rectangular aperture I _3, same as opening geometry of the rotatable rectangular aperture I ₃ It can be a degree.

At this time, the cross-sectional shape and size of the light beam passing through the rotatable rectangular diaphragm I ₃ is as follows.
Depending on the rotation angle of ₃ , the rectangular aperture is minimum when horizontal and maximum when vertical. That is, the rotatable rectangular diaphragm I
The cross-sectional shape of the light beam that has passed through ₃ is the same as the shape of the common portion (overlapping portion) of the light beam cross section and the aperture cross section. The rotatable rectangular diaphragm I ₃ has a gear mechanism (g
₁ and g ₂ ), the lens rotates in accordance with the lens position control signal / rectangle diaphragm rotation angle control signal from the focusing lens position control circuit / rectangle diaphragm rotation angle control circuit MC. The position (angle) of the rectangular opening after the rotation adjustment is a linear function of the distance signal. (The gear ratio of the gear mechanism (g ₁ , g ₂ ) is reflected in the proportional constant of the distance signal.) The usefulness of the variable throttle device used in the third embodiment is different from that in the second embodiment. It is the same. The other matters of the third embodiment are the same as those of the first embodiment.

(Fourth Embodiment) A fourth embodiment of the optical information reader according to the invention of this application will be described. The fourth embodiment is equivalent to the one obtained by replacing the vibrating mirror type scanning device and the light receiving optical system in the first embodiment with the following. FIG. 12 is a diagram showing the overall configuration of the fourth embodiment. In FIG. 12, 4 is a vibrating mirror type scanning device, and 5 is a light receiving optical system. Other elements 2-3, 6-
9 is the same as the element of FIG.

(Vibration mirror type scanning device of the fourth embodiment)
3A and 3B are views showing a vibrating mirror type scanning device used in the fourth embodiment, wherein FIG. 3A is a horizontal sectional view, FIG.
(C) is a side view. 13, 41 ₁ the reflection mirror 42 is movable unit, 46 holder, the 47 fixing yoke, 49 is a drive winding. The difference in configuration between the first embodiment and the fourth embodiment will be described. The fixed yoke 47 has a substantially U shape. The substantially U-shape is a shape in which one side of the substantially U-shape is deleted. A pair of opposite sides to 47 _1, 47 ₂ of the stationary yoke 7, which is typically a linear, can be a gentle curved shape.

The movable part 42 includes a movable part body and a rotary shaft 425.
Contains and. Movable body, while the opposite sides ₄₇ 1, 47 ₂ of the pair of fixed yoke 47 are disposed on且前surface closer (open end closer). The movable part main body and the fixed yoke 47 constitute a magnetic circuit having a substantially square V shape. The rotating shaft 425 is a fixed yoke 4.
It is arranged perpendicular to a plane including 7. Drive winding 4
9 and 49 are a pair of opposite sides 4 of the fixed yoke 47, respectively.
7 _1, 47 is wound _second winding on the front closer. Only the reflection mirror (scanning mirror) 41 ₁ is fixed to the front surface of the movable portion 42. The remaining structure of the fourth embodiment is the same as that of the first embodiment.

(Light receiving optical system of the fourth embodiment) A light receiving optical system used in the fourth embodiment will be described. Returning to FIG. 12, the light receiving optical system 5 is composed of a conventional condenser lens. The reflected light that has passed through the condenser lens 5 directly enters the photoelectric converter 7 without mediation. The other matters of the fourth embodiment are the same as those of the first embodiment.

(Fifth Embodiment) A fifth embodiment of the optical information reader according to the invention of this application will be described. In the fifth embodiment, the light receiving optical system 5 in the fourth embodiment is
This is equivalent to one in which the reflecting mirror of the vibrating mirror type scanning device is also used as a light receiving mirror while being moved to the vicinity of the focusing device 3. The fifth embodiment is the first to the fourth.
Compared with the embodiment described above, the amount of received light is slightly reduced. The other matters of the fifth embodiment are the same as those of the fourth embodiment.

(Sixth Embodiment) A sixth embodiment of the invention of this application will be described. The sixth embodiment of the invention of this application corresponds to the one in which the distance measuring device in the first embodiment is replaced with the following distance measuring device. FIG. 5 is an explanatory view of the principle of the distance measuring device 6 used in the sixth embodiment of the invention of this application. FIG. 5 (a) is its plan view (a view from above the device), FIG. (B) is a side view (viewed from the side of the device), and (C) is a diagram showing a distance measuring photoelectric converter 6S used in the distance measuring device 6 and its connection relationship.

5A to 5C, 2 is a light source for reading optical information, 41 is a vibrating mirror, 6L is a light receiving lens for distance measurement, 6S is a photoelectric converter for distance measurement, and 6A is a differential amplifier. is there. The symbol u attached to the distance measuring photoelectric converter 6S indicates the upward direction of the distance measuring photoelectric converter 6S. Reference numerals 1 _T , 2 _T , and 3 _T indicate typical positions of the object T to be read (not shown), and reference numerals 1 _S , 2 _S , and 3 _S indicate reflected light beams corresponding to these positions. The position of the scanning line (trajectory of the flying point) is shown. When the read object T moves from 2 _T to 3 _T (that is,
When approaching), the locus of the scanning line composed of the reflected light moves from 2 _S to 3 _S (that is, moves downward). This can be easily understood by referring to FIG. On the contrary, when the object T to be read moves from 2 _T to 1 _T (removes), the locus of the scanning line moves from 2 _S to 1 _S (moves upward). This can be similarly understood.

The distance measuring photoelectric converter 6S comprises two light receiving areas A and B. The shapes of the light receiving areas A and B are shown in FIG.
As shown in (C), it has a shape obtained by dividing a square or a rectangle into two equal parts by one diagonal line. When a square or a rectangle is divided along a diagonal line, the shapes of the areas A and B are right angles 3
Square, otherwise trapezoidal. The two areas A and B are electrically insulated. The photocurrent outputs I _A and I _{B in} both regions are proportional to the time (distance) that the scanning line (flying spot) passes through the surface. The vertical length of the distance measuring photoelectric converter 6S is 2c, and the distance from the center to the locus of the scanning line is d.
If (−c ≦ d ≦ c), the time for the scanning line (flying point) to pass through the area A is proportional to (c−d), and the time for passing through the area B is proportional to (c + d). _{A = p (c-d)} I B = p (c + d)

It becomes However, p is a proportional constant (depending on the intensity of light). One area A is connected to the + terminal of the differential amplifier 6A, and the other area B is connected to the-terminal of the differential amplifier 6A. The difference voltage signal V _X is obtained at the output terminal. V _X = −2 Apd (18) where A is the gain of the differential amplifier 6A. The scanning line is shown in Figure 5 (c).
The output V _A of the area _A and the output V _{B of the} area B are the same when passing through the line 2 _{S of the} above, the output V _X of the differential amplifier 6A becomes zero. When the scanning line passes over the line 3 _S (when the object T to be read is near the near point), the output V _A of the area _A becomes smaller than the output V _{B of the} area B, so the differential amplifier 6A The output V _X of V is a negative value. Scan line is line 1 _S
When passing over (when the object to be read T is near the far point)
, The output V _A of the area _A becomes larger than the output V _{B of the} area B, so that the output V _X of the differential amplifier 6A has a positive value.
At this time, the sign of d becomes negative and d = − | d |. By rewriting the above equation, the following equation is obtained. d = -V _X / 2Ap (18 ')

In order to utilize the theory of triangulation, consider a base line BL that crosses the distance measuring light receiving lens 6S (see FIG. 5B). Then, the distance from the base line BL (light receiving lens 6L for distance measurement) to the object T to be read is D _X , the distance on the base line BL from the scanning center line to the light receiving lens 6L for distance measurement is e, and the base line BL.
The distance from the (distance measuring light receiving lens 6L) to the distance measuring photoelectric converter 6S is f, and from the optical axis of the distance measuring light receiving lens 6L to one end (u side end portion) of the distance measuring photoelectric converter 6S. Let b be the distance. When the received light amount is controlled to a substantially constant value, the distance D _X to be read object T is given by the following equation. _{D X = ef / (b +} c-V X / 2Ap) (19)

The process of deriving the above equation (19) is as follows. According to FIG. 5B, the height is D _X and the base is e.
It is possible to consider a right triangle having a height of f and a base of (b + c + d). Both are clearly similar because their hypotenuses are on the same line segment 3 '. According to the theory of similarity, D _X / e = f / (b + c + d) ∴D _X = ef / (b + c + d) (20) Substituting the formula (18 ′) into the formula (20), the above formula (19) Is obtained. When the connection polarity from the distance measuring photoelectric converter 6S to the differential amplifier 6A is reversed, the following equation is used instead of the equation (19). D _X = ef / (b + c + V _X / 2Ap) (19 ′)

If the brightness of the light source is constant without being controlled, the amount of received light is inversely proportional to the square of the distance. The photocurrents I _A and I _{B in} this case are as follows. I _A = p (c−d) (D _O / D _X ) ² I _B = p (c + d) (D _O / D _X ) ² ∴V _A = _A p (c−d) (D _O / D _X ) ² V _B = Ap (c + d) (D _O / D _X ) ² where A is the gain of the amplifier. When the sum and difference of V _A and V _B are calculated, V _A −V _B = −2 Apd (D _O / D _X ) ² V _A + V _B = 2 Apc (D _O / D _X ) The ^two sides are divided to perform the division. , Ap and (D _O / D _X ) are erased, (V _A −V _B ) / (V _A + V _B ) = V _X / (V _A + V _B ) = − d / c ∴d = −cV _X / (V _A + V _B ) (21) By substituting the above equation into the equation (20), the following equation is obtained. D _X = ef / {b + c−cV _X / (V _A + V _B )} (22) (By the way, when the received light amount is controlled to a substantially constant value, V _A + V _B = 2 Apc, and the formula (22) is satisfied. Matches Equation (19).)

(Seventh Embodiment) A seventh embodiment of the invention of this application will be described. The seventh embodiment of the invention of this application corresponds to the one in which the distance measuring device in the first embodiment is replaced with the following distance measuring device. FIG. 16 is a block diagram of the input circuit of the distance measuring device used in the seventh embodiment. FIG.
In FIG. 6, 2 is a light source for bar code reading and scanning, 2D is a light source drive circuit, 6S is a photoelectric converter for distance measurement, and 9 is a centralized control device (for example, a microprocessor unit).
Also in the seventh embodiment, the light source (for example, laser) 2 for reading and scanning the bar code is used as the projection light source for distance measurement.

In principle, the distance measuring photoelectric converter 6S used in the seventh embodiment is the focusing lens position detecting photoelectric converter 32PS (FIG. 2, FIG. 2) used in the first embodiment. 3, 1
5)) and has an elongated light receiving surface, a first photocurrent output terminal t ₁ , a second photocurrent output terminal t _2, and a common electrode as shown in the figure. The first and second photocurrent outputs differ depending on the incident position of the light spot on the light receiving surface. Assuming that the length of the light receiving surface is 2c and the distance from the center position of the light receiving surface to the incident position of the light spot is d, the ratio of both currents is as follows. Process derivation of _{I 2 / I 1 = (c} + d) / (c-d) = (1 + d / c) / (1-d / c) (23) Equation (23) is as follows. First photocurrent I ₁ from the first output terminal t ₁ is proportional to the distance from the incident position of the light spot to the second output terminal t _2. Since this distance is (C / 2−d), I ₁ = p (C−d) (24) where p is a proportional constant (however, it depends on the amount of received light).
Similarly, the second photocurrent I ₂ changes from the incident position of the light spot to the first
Is proportional to the distance to the output terminal t ₁ . This distance is
Since (C / 2 + d), I ₂ = p (C + d) (25) Equation (23) is obtained by dividing equation (25) by equation (24) and eliminating proportional constant p.

Also in the seventh embodiment, the vibrating mirror type scanning device 4, the object T to be read, and the distance measuring light receiving lens 6L are used, but they are the same as those in the first embodiment. Seventh
The distance-measuring photoelectric converter 6S of this embodiment is different from that of the first and sixth embodiments as described above, but the arrangement relationship thereof is the sixth embodiment (see FIG. 5B). ) Is the same. That is, the distance measuring light-receiving lens 6L and the distance measuring photoelectric converter 6S of the seventh embodiment are arranged on the base line D. (Illustration is omitted.) At the time of distance measurement according to the seventh embodiment, the vibrating mirror 41 is stopped and light is projected in a direction perpendicular to the base line D (scanning center direction, θ = 0 ° direction). In the meantime, various control devices are operated so that the projection beam is parallel light, the aperture is opened, and the light emission output is maximized in order to increase the light receiving sensitivity of the distance measuring device 6. (However, the light emission output must be stopped within the range limited by the safety standard of light emission.) The reflected light L from the object T to be read is condensed by the distance measuring light receiving lens 6L to measure the distance. An image is formed on the light receiving surface of the photoelectric conversion device 6S. The first photocurrent _{I 1} to the first output terminal _{t 1,} the second photocurrent to the second output terminal _{t 2 I 2}
Generate.

The first and second photocurrents I ₁ and I ₂ are respectively converted into voltage signals V ₁ and V ₂ by the current-voltage converter I-V.
Is converted to. The voltage signals V ₁ and V ₂ are respectively amplified by the variable amplifier AMP, and the sample hold circuit S
Input to / H. The light projecting light source 2 is driven by the light source driving circuit 2D. The amount of light is the light output control signal LP from the centralized control device (eg, microprocessor unit) 9.
Controlled by CS. Turning on / off the light source 2
Is controlled by a turn-on (turn-off) command signal LOS.
During the distance measuring operation, in order to eliminate the influence of ambient light, the light source 2
Is pulsed. The actual lighting time is about 10 to 1000 microseconds per measurement. This time is determined to be an optimum value depending on the pulse response speed characteristics of the light projecting light source 2 and the light receiving circuit.

At the first and second output terminals, the currents I _1of and I _{2of are generated} by the ambient light even when the light projecting light source 2 is turned off.
Occurs. Current components I _1of , I derived from ambient light
_In order to eliminate the influence of _2of , the voltages V _1of and V _2of when the _light is turned off are AD-converted by the AD converter A / D, respectively, and are input as digital data to the centralized control device (eg, microprocessor unit) 9. It Immediately after that, the centralized control device (for example, a microprocessor unit) 9 issues a lighting command signal LOS to turn on the projection light source 2. The first and second sample and hold circuits S / H and S / H are respectively provided with a lighting command signal L
Voltage signals V _1ON and V _2ON at the time of lighting in synchronization with the OS
Sample and hold. The voltage signals V _1ON and V _2ON are respectively A / D converted by the AD converter A / D and input to the centralized control device (for example, a microprocessor unit) 9 as digital data.

Since each voltage data is stored as a logical value inside the centralized control device (for example, a microprocessor unit) 9, the following calculation can be easily executed. The true distance measurement data V _1t and V _2t are calculated by subtracting the voltage data V _1of and V _2of when the light is turned off from the voltage data V _1ON and V _2ON when the light is turned on. That is, V _1t = V _1ON −V _1of V _2t = V _2ON −V _2of V _2t / V _1t is calculated from both equations. _{That, V 2t / V 1t = (} V 2ON -V 2of) / (V 2ON -V 2of) (26) V 2t / V 1t is equivalent to _I 2 / _{I 1} in the above formula (23). Therefore, the above equation (26) is replaced by the above equation (23).
The distance measurement value D _X can be calculated by substituting it into I ₂ / I ₁ . _{(V 2ON -V 2of) / (} V 2ON -V 2of) = (1 + d / c) / (1-d / c) (27)

The above calculation inside the centralized control unit (microprocessor unit) 9 is usually 100 μsec.
You can do the following: In order to improve the measurement accuracy, the above measurement sequence is repeated and the average value is output. The number of repetitions is usually 10 to 20 times. Therefore, the measurement time per measurement is usually 1 msec or less. In order to improve the measurement accuracy, it is necessary to increase the projected light amount, but there is a limit as described above.

In order to improve the quantization accuracy of the A / D converter, when the lighting data V _1ON and V _2ON are both small values, the centralized control unit (microprocessor unit) 9 uses the amplification factor switching signal ACS. , Increase the amplification factor to obtain the optimum input value, and then repeat the measurement sequence. On the contrary, when the lighting data V _1ON or V _2ON exceeds the maximum input value of the A / D converter, the centralized control device (microprocessor unit)
9 reduces the amplification factor by the amplification factor switching signal ACS and then repeats the measurement sequence. These are distance measuring distance D
_This is because the intensity of reflected light that can be received changes when _X changes greatly.

(Eighth Embodiment) An eighth embodiment of the invention of this application will be described. The eighth embodiment of the invention of this application corresponds to the focusing lens position detecting means 32 in the focusing device 3 of the first embodiment being replaced by the following focusing lens position detecting means. The intensity of light (that is, side light) in a direction away from the optical axis of the light source (for example, laser) 2 by an angle φ is
It is a decreasing function of the angle φ. Therefore, if the light receiving surface of the focusing lens position detecting position lens 32PL moves forward (the x coordinate of the focusing lens 31 increases), the received light amount increases, and if it moves backward (the focusing lens 31). If the x-coordinate of) decreases, the amount of received light decreases. That is, when the focusing lens 31 moves forward, the output of the focusing lens position detecting photoelectric conversion element 32PS increases, and when the focusing lens 31 moves backward, the output of the photoelectric conversion element 32PS decreases. . That is, the output (position detection signal) of the focusing lens position detecting means 32 is a monotonically increasing function of the x coordinate of the focusing lens 31. Therefore, the x-coordinate of the focusing lens 31 can be obtained by obtaining the inverse function of the monotonically increasing function.

(Other Embodiments) Other embodiments will be described. Other examples, by combining the matters in the above-mentioned examples and the following matters,
Is generated. (A) The focusing lens position detecting photoelectric converter 3 in the focusing lens position detecting means 32 of the focusing device 3 of the first embodiment.
The 2PS can be composed of a large number of photoelectric conversion elements and a position detecting arithmetic circuit. (B) The driving means in the vibrating mirror type scanning device 4 of the first embodiment can be composed of a piezoelectric electromechanical converter. (C) The focusing lens moving means 33 in the focusing device 3 of the first embodiment can be constructed as a movable iron piece. (D) The centralized control device 9 can be composed of an ASIC. (E) The electronic circuit portion in each embodiment can be integrated with the centralized control device 9 into an IC to form a system-on-chip.

[0081]

Since the invention of this application is constituted as described above, it is possible to exert remarkable effects as described in (a) to (1) below. (A) An optical information reading device with an ultra-long reading depth that can accurately read optical information even when the reading distance is not constant because the object to be read is at a far point or a near point Can be realized. In other words, it is possible to realize an optical information reading device having a very large reading range. (B) A compact, lightweight, low-cost focusing device and distance measuring device can be realized. As a result, it is possible to realize an optical information reading device which is small, lightweight and low cost as a whole. (C) It is possible to realize a hand-held optical information reader equipped with a compact, lightweight, and low-cost focusing device and distance measuring device.

(D) By adding a variable diaphragm device to the focusing device, when the object T to be read is at a near point,
Prevents the resolution from rising too high due to the beam waist becoming too thin, and prevents the resolution from decreasing too much due to the beam waist becoming too thick when the object T to be read is at the far point.
Therefore, the resolution is maintained in an appropriate range over the ultra-long depth, and when the object T to be read is at the near point, a sharp increase in the beam diameter before and after the near point is prevented, thereby performing scanning. It is possible to realize an optical information reading apparatus in which the variation of the resolution due to the deflection of the beam is prevented and the S / N ratio is greatly improved. (E) Optically controlling the brightness (and therefore the light amount) of the light source based on the linear function of the distance measurement signal and / or the scanning angle signal to maintain the received light amount of the photoelectric converter 7 in an appropriate range. An information reading device can be realized. (F) By using an oscillating mirror type scanning device having a scanning mirror on the front surface and a light receiving mirror on the rear surface, that is, by using the light receiving mirror on the rear surface exclusively for light reception, the light receiving aperture is increased, and thus the amount of received light is increased. It is possible to realize the optical information reading device.

(G) By adjusting the scanning angle using the distance measurement data, it is possible to secure the necessary reading width at both the near point and the far point. (H) By controlling the laser light power using the distance measurement data, it is possible to stabilize the light receiving gain and the visibility. (I) It is possible to contribute to stabilization of the light receiving gain by controlling the light receiving gain using the distance measurement data. (J) The frequency band of the electrical analog signal can be controlled by adjusting the scanning speed using the distance measurement data. (K) By adjusting the laser light power or the light receiving gain using the scanning angle data, it is possible to compensate for the decrease in the amount of received light on both sides of the scanning. (1) Using the scanning angle data, it is possible to correct the shift of the focused object due to the optical path difference between the scanning center and both sides.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a first embodiment of an optical information reading device according to the invention of this application.

FIG. 2 is an operation principle diagram of the automatic focusing device used in the first embodiment.

FIG. 3 is a vertical cross-sectional view of an optical focusing unit forming a main part of the automatic focusing device.

FIG. 4 is a principle explanatory view of a first distance measuring device used in the first embodiment.

FIG. 5 is a principle explanatory view of a second distance measuring device used in the first embodiment.

FIG. 6 is a horizontal sectional view and a vertical sectional view of a vibrating mirror type scanning device used in the first embodiment.

FIG. 7 is an operation principle diagram of a variable aperture device used in a second embodiment of the optical information reading device according to the invention of this application.

FIG. 8 is an operation principle diagram of a focusing device and a variable aperture device used in a third embodiment of the optical information reading device according to the invention of this application.

FIG. 9 is a vertical cross-sectional view of a laser beam after passing through a focusing lens.

FIG. 10 is a graph showing a waist position and a diameter of a laser beam after passing through a fixed diaphragm.

FIG. 11 is a graph showing a waist position and a diameter of a laser beam after passing through a variable diaphragm.

FIG. 12 is a diagram showing the overall configuration of a fourth embodiment of the optical information reading device according to the invention of this application.

FIG. 13 is a diagram showing a scanning vibrating mirror type scanning device used in the fourth embodiment.

FIG. 14 is a diagram showing a light focusing position of a focusing lens.

FIG. 15 is a block diagram of a focusing lens position control circuit.

FIG. 16 is a block diagram of an input circuit of a distance measuring device used in a seventh embodiment of the invention of this application.

FIG. 17 is a block diagram of a light source drive circuit.

FIG. 18 is a diagram illustrating the operating principle of a conventional autofocus scanner.

FIG. 19 is a perspective view of a physical distribution sorting system using a conventional autofocus scanner.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 case 2 light source 2D light source drive device 3 automatic focusing device (automatic focusing system) 31 focusing lens 32 focusing lens position detecting means 32PL focusing lens position detecting position lens 32PS focusing lens position detecting photoelectric converter ( Element) 32PC Focusing lens position calculation circuit 33 Focusing lens moving means 33C Movable wire ring (excitation wire ring) 33CD Focusing lens position drive circuit 33M Permanent magnet 33Y Yoke 34 Focusing lens position servo circuit 35 Electronic Voltage divider 3B Lens barrel (barrel) 3H Focusing lens holder 3LL Focusing lens position detecting laser light 3SP Support spring 3U Optical focusing unit 4 Vibrating mirror type scanning device 41 ₁ First vibrating mirror (scanning mirror) 41 ₂ second vibrating mirror (light receiving mirror) 42 movable portion 421 movable magnet 422 movable yoke (yoke) 42 Magnetic 425 pivot shaft 46 holder 47 fixed yoke 47 ₁ opposite sides 48 fixed magnet 49 driving line wheels 5 receiving optical system 6 ranging apparatus across flats 47 ₂ fixed yoke fixed yoke (rangefinder) 6A differential amplifier 6C Distance-measuring means 6L Distance-receiving lens 6P Distance-measuring projector 6R Distance-measuring photoelectric converter 6s Distance-measuring photoelectric conversion element 6S Distance-measuring photoelectric converter 7 Photoelectric converter (photoelectric converter) 8 Signal processing unit 9 Centralized control device (eg, microprocessor unit) 10 Variable aperture device DS Distance signal I Variable aperture IC Variable aperture control circuit LB Laser beam M Electric motor MC Focusing lens position and aperture rotation angle control circuit MS Laser diode monitoring signal p Optical information pattern (eg bar code symbol) SB Scanning beam T Object to be read (eg label) TS Temperature sensor VD Electronic partial pressure vessel

Claims (43)

[Claims] 1. A light source (2) which emits a light beam for scanning an object (T) to be read, and a focus for focusing the light beam emitted from the light source (2) on the object (T) to be read. A focusing device (3), an oscillating mirror type scanning device (4) for periodically reflecting and deflecting the light beam in a horizontal plane, and a reflected light reflected from the object to be read (T) are predetermined. A light receiving optical system (5) for collecting light, a photoelectric converter (7) arranged at the predetermined position for converting the reflected light into an electric analog signal, and the photoelectric converter (7). A signal processing unit (8) connected to the output terminal of the device, a distance measuring device (6) for measuring the distance from the vibrating mirror type scanning device (4) to the object to be read (T), and these elements. And a housing (1) for accommodating all of the above, and the distance measuring device (6) and the focusing device (3) are The distance signal from the distance measuring device (6) to provide a position command signal to the focusing device (3), a hand-held optical information reading device formed by connecting. 2. The handheld optical information reader according to claim 1, wherein the light source (2) is a visible light semiconductor laser that emits a visible light beam. 3. The light source (2) is a surface-emitting type LE.
2. The handheld optical information reader according to claim 1, wherein D has a mesa structure having an extremely small diameter. 4. The focusing device (3) includes a focusing lens (31) for focusing the light beam emitted from the light source (2) on the object to be read (T), and the focusing lens (31). Focusing lens support means (39) for supporting the focusing lens (31) so as to be displaceable only in the optical axis direction, and a focusing lens capable of moving the focusing lens (31) in the optical axis direction. The focusing lens position servo circuit (34) includes a moving unit (33) and a focusing lens position servo circuit (34), and the focusing lens position servo circuit (34) receives the position command signal and converts the position command signal into a position control signal, 2. The handheld optical information reading device according to claim 1, wherein the optical information reading device is configured to be provided to the lens moving means (33). 5. The handheld optical information reader according to claim 4, wherein the focusing lens (31) is made of a plastic material. 6. The handheld optical information reader according to claim 4, wherein the focusing lens support means (39) includes a cylindrical or annular focusing lens holder 3H. 7. The handheld optical information reading device according to claim 6, wherein the focusing lens supporting means (39) further includes a plate-shaped supporting spring. 8. The support springs are a pair of support springs 3S.
P, 3SP, and the support springs 3SP, 3SP are
The handheld optical information reading device according to claim 7, wherein the focusing lens holder 3H is arranged so as to be sandwiched from the front and rear. 9. The focusing device (3) comprises a lens barrel (barrel).
The hand-held optical system according to claim 7, further comprising: 3B, said focusing lens supporting means (39) is housed in said lens barrel 3B, and a peripheral edge portion of said support spring is fixed to an inner wall of said lens barrel 3B. Information reader. 10. The focusing lens moving means (33) includes an electromagnetic drive mechanism, and the electromagnetic drive mechanism includes an excitation coil 33C, a permanent magnet 33M, and a yoke 33Y. The handheld optical information reader according to claim 4. 11. The excitation coil 33C and the permanent magnet 3
3M and the yoke 33Y are both formed in a ring shape,
Moreover, they are coaxially arranged in this order from the inside, and the permanent magnet 33M and the yoke 33Y are fixed sides,
11. The handheld optical information reading device according to claim 10, wherein the excitation coil 33C is a movable side, and the movable coil 33C is connected in series to a focusing lens support means (39). 12. The focusing device (3) is a lens barrel (barrel).
The handheld optical information reading device according to claim 10, further comprising: 3B, the electromagnetic drive mechanism is housed in the lens barrel 3B, and a peripheral portion of the yoke 33Y is fixed to an inner wall of the lens barrel 3B. apparatus. 13. The focusing device (3) further includes a focusing lens position detecting means (32), and the focusing lens position detecting means (32) emits light from the focusing lens (31). The focusing lens position servo circuit (34) is configured to detect a position in the axial direction and output a position detection signal, and the focus lens position servo circuit (34) receives the position command signal and the position detection signal to form a position control signal. 5. The hand-held type according to claim 4, wherein the focusing lens moving means (33) is applied to the focusing lens moving means (33) and the focusing lens moving means (33) is stopped when the difference between the two signals becomes zero. Optical information reader. 14. The focusing lens position detecting means (32)
Is the position lens for focusing lens position detection (32P
L) and a photoelectric converter (32PS) for detecting the focusing lens position
And a focusing lens position calculation circuit (32PC), according to claim 13. 15. The focusing device (3) includes a focusing lens holder 3H and a lens barrel 3B, and the focusing lens position detecting position lens (32P).
L) is embedded in the peripheral wall portion of the focusing lens holder 3H in order to guide it to the outside through a corresponding peripheral wall portion, in order to guide the ambient light that has reached a predetermined location on the inner peripheral portion of the focusing lens holder 3H to the outside. 32PL) has a through hole at a position where the optical axis (extension line) of the lens barrel 3B intersects the peripheral wall portion of the lens barrel 3B, and the focusing lens position detecting photoelectric converter (32PS) is arranged in the through hole. 15. The handheld optical information reading device according to claim 14, wherein the position converging point of the position lens (32PL) and the light receiving surface of the photoelectric converter (32PS) are aligned with each other. 16. The cross-sectional shape of the focusing lens position detecting position lens (32PL) and the sectional shape of the focusing lens position detecting light receiver are both vertically long.
The handheld optical information reader according to claim 14. 17. A variable aperture means (10) is further included,
The variable aperture means (10) includes a variable aperture (I) and an aperture control circuit (IC), and the variable aperture (I) is arranged in front of or behind the focusing device (3). The diaphragm control circuit (IC) and the distance measuring device (6) are
The handheld optical information reader according to claim 4, wherein the distance signal from the distance measuring device (6) is connected to the diaphragm control circuit (IC) so as to be supplied as a diaphragm command signal. 18. The aperture shape of the variable aperture (I) is
18. The handheld optical information reader according to claim 17, which is circular. 19. The aperture shape of the variable aperture (I) is
18. The handheld optical information reader according to claim 17, which is in the shape of a parallelogram. 20. The aperture shape of the variable aperture (I) is
18. The handheld optical information reader according to claim 17, which is in the shape of a quadrangle. 21. The aperture shape of the variable aperture (I) is
18. A shape in which the lateral width in the upper part and / or the lower part is expanded stepwise from the lateral width in the central part.
The handheld optical information reader described. 22. A diaphragm hole shape of the variable diaphragm (I) is
18. The shape in which the lateral width in the upper part and / or the lower part is continuously enlarged as compared with the lateral width in the central part.
The handheld optical information reader described. 23. The aperture shape of the variable aperture (I) is
The lateral width in the upper part and / or the lower part is intermittently larger than the lateral width in the central part.
The handheld optical information reader described. 24. The focusing lens moving means (33) comprises:
Feed screw mechanism (FM) and feed screw mechanism driving means (F
The handheld optical information reader according to claim 4, comprising D) and a focusing lens position control circuit (MC). 25. The feed screw mechanism (FM) includes a feed screw (FS), and the feed screw (FS) is provided on an outer peripheral portion of the focusing lens holder (3H).
The handheld optical information reader described. 26. The feed screw mechanism driving means (FD)
Includes a gear mechanism (g ₁ , g ₂ ) and an electric motor (M), and the gear mechanism (g ₁ , g ₂ ) is a first gear (g ₁ ) and a second gear (g ₂ ). And the first gear (g ₁ ) is connected to the electric motor (M), and the second gear (g ₂ ) is connected to the outer periphery of the focusing lens holder (3H). The handheld optical information reader according to claim 24. 27. Further, the variable throttle (I ₃₎ containing, the variable throttle (I _3), the feed screw mechanism handheld optical of claim 24, wherein formed by connecting to work with (FM) Information reader. 28. The oscillating mirror scanning device (4) comprises:
A vibrating mirror (41 ₁ ) for reflecting and deflecting the light beam emitted from the light source (2), and the vibrating mirror (41)
₁ ) An electromagnetic drive means for vibrating the electromagnetic drive means, the electromagnetic drive means includes a fixed portion and a movable portion, and the vibrating mirror (41 ₁ ) and the movable portion are integrally configured. Item 1. The handheld optical information reader according to Item 1. 29. The handheld optical information reading device according to claim 28, wherein the drive means is an electromagnetic drive means. 30. The vibrating mirror type scanning device (4) includes a first vibrating mirror (41 ₁ ) for reflecting and deflecting a light beam emitted from the light source (2), and the first vibrating mirror (4 ₁ ). 41 ₁ ) 2nd fixed on the rear surface
Vibrating mirror (41 ₂ ), and an electromagnetic driving unit that vibrates the first vibrating mirror (41 ₁ ) and the second vibrating mirror (41 ₂ ), and the light receiving optical system (5) The so-called demand-held optical information reading device according to claim 1, which comprises a deflecting means (5CP) and the second vibrating mirror (41 ₂ ). 31. The distance measuring device (6) includes a distance-measuring light receiving lens (6L) for receiving reflected light from the object to be read (T), and a measuring device for converting the reflected light into an electrical analog signal. 2. The handheld optical information reader according to claim 1, further comprising a distance photoelectric converter and a distance measuring calculation means (6C). 32. The distance-measuring photoelectric converter comprises a photoelectric conversion element (6s) having a small horizontal light-receiving area size, and the distance-measuring calculation means (6C) determines a maximum point of received light amount, The object to be read (T) is based on the maximum time of the received light amount.
The handheld optical information reading device according to claim 31, wherein the distance to is calculated. 33. The distance measuring photoelectric converter includes two areas (A) and (B) formed by dividing a square or rectangular light receiving area into two by oblique lines. The arithmetic means (6C) includes a differential amplifier (6A), and the two light receiving regions (A) and (B) are respectively connected to the first and second input terminals of the differential amplifier (6A). 32. The handheld optical information reader according to claim 31. 34. A light source (2) for emitting a light beam for scanning an object (T) to be read, and a light source (2) for focusing the light beam emitted from the light source (2) on the object (T) to be read. A focusing device (3), an oscillating mirror type scanning device (4) for periodically reflecting and deflecting the light beam in a horizontal plane, and a reflected light reflected from the object to be read (T) are predetermined. A light receiving optical system (5) for condensing light, a photoelectric converter (7) arranged at the predetermined position for converting the reflected light into an electric analog signal, and the photoelectric converter (7). A signal processing unit (8) connected to the output terminal of, and a distance measuring device (6) for measuring the distance from the vibrating mirror type scanning device (4) to the object to be read (T). The focusing device (3) focuses the light beam emitted from the light source (2) on the object to be read (T). ) A focusing lens (31) for tying up the lens, a focusing lens support means (39) for supporting the focusing lens (31) so that it can be displaced only in the optical axis direction, and the focusing lens. A focusing lens moving means (33) capable of moving (31) in the optical axis direction and a focusing lens position servo circuit (34) are included, and the distance measuring device (6) and the focusing device are included. (3) is the focusing lens position servo circuit (34) connected so that the distance signal from the distance measuring device (6) is given to the focusing device (3) as a position command signal. Is an optical information reading device configured to receive the position command signal, convert the position control signal into a position control signal, and apply the position control signal to the focusing lens moving means (33). 35. The focusing lens moving means (33) includes an electromagnetic drive mechanism, and the electromagnetic drive mechanism includes an excitation coil 33C, a permanent magnet 33M, and a yoke 33Y. The optical information reader according to claim 34. 36. The focusing device (3) further includes focusing lens position detecting means (32), and the focusing lens position detecting means (32) is configured to detect the light of the focusing lens (31). The focusing lens position servo circuit (34) is configured to detect a position in the axial direction and output a position detection signal, and the focusing lens position servo circuit (34) receives the position command signal and the position detection signal, and outputs a difference signal between the two signals. 35. The optical information reading device according to claim 34, wherein the difference signal is provided to the focusing lens moving means (33) as a position control signal. 37. Further comprising variable aperture means (10),
The variable aperture means (10) includes a variable aperture (I) and an aperture control circuit (IC), and the variable aperture (I) is arranged in front of or behind the focusing device (3). The diaphragm control circuit (IC) and the distance measuring device (6) are
The optical information reader according to claim 34, wherein the distance information from the distance measuring device (6) is connected to the diaphragm control circuit (IC) so as to be supplied as a diaphragm command signal. 38. The focusing lens moving means (33) comprises:
Feed screw mechanism (FM) and feed screw mechanism driving means (F
The optical information reading device according to claim 34, which comprises D) and a focusing lens position control circuit (MC). 39. A focusing lens (31) for focusing a light beam emitted from a light source (2) on the object (T) to be read, and the focusing lens (31), Focusing lens support means (39) for movably supporting only the direction, focusing lens moving means (33) for moving the focusing lens (31) in the optical axis direction, and focusing lens A position servo circuit (34), the focusing lens position servo circuit (34) receives the position command signal, converts the position command signal into a position control signal, and supplies the position control signal to the focusing lens moving means (33). , A focusing device for an optical information reader, which is configured. 40. The focusing device (3) further includes a focusing lens position detecting means (32), and the focusing lens position detecting means (32) emits light from the focusing lens (31). The focusing lens position servo circuit (34) is configured to detect a position in the axial direction and output a position detection signal, and the focusing lens position servo circuit (34) receives the position command signal and the position detection signal, and outputs a difference signal between the two signals. 40. The focusing device for an optical information reading device according to claim 39, wherein the focusing signal is provided to the focusing lens moving means (33) as a position control signal. 41. A distance-measuring light-receiving lens (6L) for receiving reflected light from the object to be read (T), a distance-measuring photoelectric converter for converting the reflected light into an electrical analog signal, and a distance-measuring device. Distance measuring device for an optical information reading device, including: 42. The distance measuring photoelectric converter is composed of a photoelectric conversion element (6s) having a small horizontal light receiving area size, and the distance measuring arithmetic means determines a received light amount maximum point, and the received light amount is determined. The distance measuring device for an optical information reading device according to claim 41, wherein the distance to the object to be read (T) is calculated based on the maximum time point. 43. The distance measuring photoelectric converter includes two light receiving areas (A) and (B) which are formed by dividing a square or rectangular light receiving area into two diagonal lines. The calculation means for use includes a differential amplifier (6A), and the two light receiving regions (A) and (B) are respectively connected to the first and second input terminals of the differential amplifier (6A). 42. The distance measuring device for an optical information reading device according to claim 41, wherein said distance measuring operation means multiplies the output of said differential amplifier (6A) by a proportional constant.