JPH05233862A - Optical scanning device and method therefor - Google Patents

Abstract

PURPOSE:To simplify target matching, to improve read efficiency and to shorten read time by irradiating a symbol with laser light generated from a head so as not to be visually easily identified, and condensing laser light reflected from the symbol so as not to be easily identified concerning the angle of view. CONSTITUTION:The part of incidental laser light passed through an opening iris is deflected to a scanning mirror 66 by an optical assembly along an optical axis 102 in a head 10, and the scanning mirror 66 passes the laser light colliding there forward through a window 68 along an optical axis 104 and reflects it on the symbol. When the scanning mirror 66 is activated by a trigger switch 32, oscillating motion is executed and in the case of linear scanning, the incidental laser light is swept across all the bars of the symbols in a lengthwise direction. The returned part of the reflected laser light is condensed by a spherical condensing mirror 76 and reflected to a photosensor 80. The photosensor 80 detects the variable luminance of the condensed laser light over the view extending beyond a linear scanning area and generates an electric signal showing variable light intensity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device for reading symbols such as bar code symbols, and more particularly in a laser scanning system which is user-held and capable of aiming at each symbol being read. You can
Lightweight, multi-component portable laser diode scanning head. More specifically, the present invention visually searches each symbol that is read when the head emits or receives light that is virtually invisible to the user and is virtually invisible, and in some cases Is a light aiming device for tracking, a trigger for controlling the light aiming device,
Laser diode optics assembly, optics that reflects aiming light, but transmits light that is not easily visually recognizable, scanning, focusing and focusing mirror system, and single or multiple components as required Can be housed in a single handle on the head, or in a replaceable handle that is removable from the head, with a replaceable component design and selected transparent area of the head that allows light to pass through it. And a light-shielding cover for preventing this.

[0002]

BACKGROUND OF THE INVENTION Various optical readers and optical scanning systems optically detect a bar code symbol applied to an object to identify the object by optically reading the symbol on the object. To read. The bar code symbol itself is a coded pattern consisting of a series of bars of different widths, separated from each other by spaces and having different widths, and the bars and spaces having different light reflection properties. Optical readers and optical scanning systems decode the coded patterns into multiple alphanumeric representations that describe the object. This general type scanning system is disclosed, for example, in U.S. Pat. Nos. 4,251,798, 4,360,798, 4,369,361, and US Pat.
4,387,297, 4,409,470, and 4,
No. 460,120.

As disclosed therein, the particular advantages of such a scanning system are, among other things, the fact that a handheld, portable laser scanning head held by the user emits laser light to the symbol to be read. Directing the laser light, repeatedly scanning the laser light in a series of scans across the symbol, detecting the laser light reflected from the symbol in the scanned laser light, and decoding the reflected light detected. There was The laser light is usually, but not always, emitted by a helium-neon gas laser which emits red laser light at a wavelength of about 6328 angstroms. Since this red laser light is visible to the user, the user can easily aim and aim the head and position and hold the emitted red laser light on and across the symbol during scanning.

However, laser light is used, for example, in US Pat. No. 4,38.
7,297, 4,409,480 and 4,460,12
In the technique of emitting a laser beam from a semiconductor laser diode, as described in No. 0, when the laser beam emitted from the laser diode cannot be easily visually recognized by the user, it is more difficult to aim the head on the symbol. become. In some types of laser diodes, the laser light is emitted at a wavelength of about 7800 angstroms,
It is very close to the infrared and lies on the border between visible and invisible light. This laser diode light is visible to the user in a dark room, but invisible in a bright environment where ambient light blocks the laser diode light. Furthermore, when the laser diode light is moved, for example, by being swept across a symbol, the laser diode light is swept at multiple times per second, for example at a high velocity of 40 times per second, so that the laser diode light is in a dark room. Even, it was invisible to the user. Therefore, one or several factors such as the wavelength of the laser light, the intensity of the laser light, the intensity of ambient light in the environment in which the laser light is emitted, the scanning speed and other factors may cause the laser diode to Light is effectively "invisible" or "not easily visually recognizable."

However, this laser diode light is not easily visually recognizable, so that the user can easily aim the laser diode light at the symbol, at least without considerable difficulty and practical effort. There wasn't. The user expects, by trial and error, to aim and scan the laser diode light to be correctly positioned on and across the symbol, and the scanning system will typically turn on the indicator lamp, Or, the sound signal (buzzer) was sounded, and it was necessary to wait until the symbol was successfully decoded and the signal was read. This search method has been an inefficient and time consuming symbol reading technique, especially for applications where a large number of symbols need to be read every hour, every day.

However, in the circumstance of a laser scanning head, which is desired to be as light, compact, efficient, inexpensive and easy to use as possible, the laser diode light is not easily visually recognizable. Despite their properties, laser diodes were an advantage over helium-neon gas lasers. This is because the laser diode is smaller and lighter than such a gas laser, consumes less electric power (DC supply voltage is 12 V or less), and has a large synchronous detection and signal / noise ratio (S / N ratio). This is because it can be directly modulated in order to do so.

[0007]

However, in spite of the above-mentioned advantages, in addition to the invisibleness, the laser diode light has a certain optical property, so that the laser diode light can be provided outside the head at a predetermined level. Focus on a desired spot size (eg, a 6-12 mil circular spot) on the reference plane, and use this spot size with a given tolerance on both sides of the reference plane for a given depth of focus, or depth of field, ie, within the field of view. It was not easy to successfully decode the symbol at the position and keep it within a readable effective distance. For example, since the wavelength of the laser diode light is long compared to the case of a helium-neon gas laser,
For the same spot size, the effective distance becomes shorter. The laser diode light is more divergent, the divergence is different on different planes, and it is not radially symmetrical. Thus, gas laser light has the same small divergence angle of about 1 milliradian in all planes perpendicular to the longitudinal direction of light propagation, whereas laser diode light has diode p-n
It has a large divergence angle of about 200 milliradians in the plane parallel to the joint surface, and about 6 in the plane perpendicular to the pn joint surface.
It has a larger divergence angle of 00 milliradians. In the single transverse mode (TEMOO), the gas laser light has a radially symmetrical, generally circular cross section, whereas the laser diode light has a radially asymmetric, substantially elliptical cross section. is doing.

For example, in a so-called geometrical method for solving the above-mentioned focusing problem and overcoming the radially asymmetric nature of the laser diode light, located at a distance of about 31/2 inches from the head. When the beam spot was focused so that it had a spot diameter of about 9.5 mils at the reference plane, an optical power greater than 80 times was obtained. However, at such high magnifications, the use of a single optical focusing element would have to be manufactured, positioned and adjusted very precisely (see, eg, US Pat. No. 4,409,470). As pointed out in U.S. Pat.No. 4,387,297, to employ highly divergent laser diode light and to distribute the magnification between the elements,
When using multiple optical focusing elements in a lens system designed to have a large numerical aperture, i.e., an aperture of 0.25, the mechanical tolerances of each element become more lenient and the positioning And the adjustment procedure becomes easier. However, multiple optical elements occupy more space in the head compared to a single element, adding weight and cost.

In addition, in some cases, during scanning across the symbol, to avoid voids within the symbol and dust on the symbol, and to make the light-dark transition more abrupt, the spot of the elliptical laser diode light must be This was sometimes desirable over a circular spot of gas laser light, but such an advantage would be obtained if a longer dimension elliptical spot was positioned along the height of the symbol. It was Therefore, in order to obtain such desirable features, the laser diode light had to be properly positioned in a particular orientation with respect to the symbol. If the symbols are randomly oriented with respect to the laser diode light, the head has to be manipulated frequently in order to orient the laser diode light with respect to the head. By this,
The procedure for reading symbols with laser diode light is no longer efficient, especially in the case of large-scale processing, and the time-consuming situation is exacerbated. It is possible to use an anamorphic collimator to make the elliptical laser diode light spot circular, but this has further increased the number of optical elements, space, weight and cost.

Furthermore, another problem with both conventional gas laser and laser diode laser scanning heads has been the difficulty in adapting to different applications. There are different applications for different end users. For some users, the reflected light detected is decoded into data that describes the symbol, and some electronics want the electronics to control this decoding to be implemented in the head, which is then placed away from the head. Some users want to be done. Furthermore, user requirements may be different regarding whether to place the rechargeable power supply or data storage device in the head or away from the head. Therefore, conventional laser scanning systems must be more or less customized for each user, which is not desirable for both manufacture and sale. Furthermore, if the user wanted to change the standards of the system, the user had to either give up the change or obtain another system.

Yet another problem with conventional laser scanning heads is that each has a separate light transmitting window. The individual windows are separate pieces that must be glued in place, so that over time, the glued parts of the windows may come apart, especially if the head is subjected to mechanical shock or abuse. It was Once the window is removed, moisture, dust and other contaminants can easily enter the inside of the head, which may cover the internal optical and electronic components and interfere with intended operation.

The basic object of the invention is to solve the above-mentioned problems in conventional laser scanning systems.

Yet another object of the present invention is to allow the user to easily aim the head, and more particularly to direct the visually indistinguishable laser light emitted from the head to the symbol, or to the symbol. The purpose is to be able to collect reflected laser light that is reflected from and cannot be easily visually identified.

Yet another object of the present invention is that the user can easily see laser light emitted from a semiconductor laser diode before and during scanning of a symbol that is not easily visually identifiable by a user over and across the symbol. Is to be able to aim at.

Still another object of the present invention is to eliminate the need for trial-and-error search operation when aiming semiconductor laser diode light on a symbol, especially when the effective distance is long.

Still another object of the present invention is to increase the efficiency and the time required for optically reading a symbol with semiconductor laser diode light.

Still another object of the present invention is to accurately locate a symbol with a semiconductor laser diode-based scanner before scanning and to accurately track a symbol with a semiconductor laser diode-based scanner during scanning. Is.

Another object of the present invention is to produce a single high precision, high magnification optical focusing element or to precisely align with respect to a diode, and to provide a plurality of optical focusing elements. A semiconductor laser diode with a substantially elliptically shaped cross-section, high divergence, radial asymmetry, and long wavelength without the need to use an element to occupy more space in the head. , To easily focus to a desired spot size on a predetermined reference surface outside the head, and to keep within the spot size with a predetermined tolerance on both sides of the reference surface within a predetermined depth of field.

Another object of the present invention is a fixed reflection mirror mounted on or fixed to a fixed concave condenser mirror for transmitting semiconductor laser diode light, and a lightweight, substantially flat mirror. Efficient and compact optical reflective optical path assembly with novel optical elements including an efficient scanning mirror in the head.

Yet another object of the present invention is to provide a manually depressible trigger switch having multiple switching positions for controlling the operation of the light aiming mechanism and the operation of the laser scanning system. .

Yet another object of the present invention is to accommodate different components within a single handle mounted on the head, or a plurality of easily replaceable handles, to easily accommodate the different needs of different users. It is to provide a modular design of the components in the head, in a form that is possible.

Yet another object of the present invention is to provide the user with optical reading of symbols, especially black and white symbols used in industrial applications and bar code symbols of the type known as Universal Product Code (UPC). By providing an extremely lightweight, streamlined, small, handy, fully portable, easy-to-operate, and fatigue-free laser diode scanning head and / or system that can be fully retained by is there.

Another object of the present invention is to seal the inside of the head from contaminants.

[0024]

To achieve the above and other objects, one of the features of the present invention is to provide a handy type laser scanning head in a laser scanning system for reading a symbol aimed by the head. It is in the light aiming mechanism used for aiming. Some components are conventionally mounted in the head. For example, a device such as a semiconductor laser diode or possibly a gas laser is included in the head for emitting incident laser light. For example, a convex lens, a concave lens,
An optical device, such as a reflecting mirror or other optical element, is also provided in the head to optically modify or form the incident laser light, positioned along the first optical path, outside the head, and incident laser light. The laser light is directed in the direction of a reference plane that is substantially perpendicular to the propagation direction of the laser beam, and is directed to a symbol in the range of the effective distance near the reference plane. For convenience, the symbol located between the reference plane and the head is
Hereinafter, the close-in symbol (close-up symbol) and the symbol located on the opposite side of the reference plane away from the head will be referred to as the far-out symbol (extremely distant symbol).

The laser light is reflected from the symbol and at least a return portion of the reflected laser light is separated from the symbol by a second
It advances to the head again along the optical path of. A scan motor, having a reciprocally oscillating output shaft, mounted on a reflective surface, such as a scan mirror, is mounted in the head to scan the symbol, and preferably sweeps multiple times per second during the scan. Iteratively scans symbols across symbols. The return portion of the reflected laser light has a variable light intensity across the symbol during scanning because, in the case of a bar code symbol, the bar and space forming the symbol have different light reflection properties. ..

The head is further equipped with a sensor, for example a photodiode or photodiodes, which detects and detects the varying light intensity of the returning portion of the laser light reflected over the field of view. Generating an analog electrical signal indicative of the varying light intensity produced. A signal processor is also provided in the head for processing the analog electrical signal and typically processing the analog electrical signal into a digitized digital electrical signal that can be decoded into data describing the symbol being scanned. .. The scanning device operates to manipulate the incident laser light itself across the symbol and / or the field of view of the sensor.

Although not always, decoding / control electronics are optionally provided within the head or at a location remote from the head. Decoding / control electronics decodes the digitized signal into the aforementioned data, determines that the symbol was successfully decoded, and terminates reading the symbol when it is verified that the symbol was successfully decoded. Perform an action. A reading means is provided in the head and is operatively connected to the laser light generator, the scanning device, the sensor, the signal processing device, and the decoding / control device, and operates to activate these devices. It is started by the activation of the trigger device of the formula. The trigger device is activated once for each symbol in each order. In the preferred embodiment, activation of the triggering device activates the decoding / controlling device, which in turn activates the laser light generating device, the scanning device, the sensor and the signal processing device.

In typical applications, the head held in the user's hand is aimed at each symbol to be read, and when the symbol is located, the user activates the trigger device to begin reading. When the decoding / control device has finished reading the symbol, it will automatically inform the user so that the user can turn his attention to the next symbol and repeat the procedure.

As described above, the fact that the incident laser beam or the reflected laser beam cannot be easily visually recognized is caused by the factors such as the wavelength of the laser beam, the intensity of the laser beam, the intensity of the ambient light, the scanning speed, and other factors. It may occur due to one or more of the factors, in which case a problem occurs. Due to such "invisibility", the user cannot see the laser beam, even if the laser beam is located on the symbol, and the scanning laser beam is not visible over the entire length of the symbol. I can't know if I'm scanning.

Therefore, when such a visually unrecognizable laser beam is utilized, the user can visually position the head with respect to each symbol by using the aiming light mechanism according to the present invention. It becomes easy to match. The aiming light mechanism includes an activatable aiming light source, for example, a visible light emission that is mounted in the head and is operatively connected to a trigger device to generate aiming light that is easily visible to a user when activated by the trigger device. A diode, which is also mounted in the head, directs the aiming light along the optical path of the aiming light from the aiming light source to the reference plane, and thus to each symbol, illuminating at least a portion of each symbol so that it is visible. And a sighting device for the user to locate the position of the symbol. The optical path of the aiming light is inside one or both of the first optical path and the second optical path that are part of the optical path outside the head, and preferably extends parallel to these optical paths. This makes it easier for the user to aim the head correctly at each symbol read.

In a preferred embodiment, the aiming light mechanism is adapted to direct a single illumination beam at each symbol to illuminate a generally circular spot area within the field of view, preferably near the center of the symbol. This single spot area is fixed during scanning of the symbol, or remains stationary, allowing the user to see both close-in and far-out symbols both before and during scanning. It would be even more advantageous if the location could be found. However, one of the drawbacks associated with such stationary single light aiming is that the user is unable to follow a linear scan of the scanning light across the symbol during scanning. In other words, the user does not know the end position of the laser scan and thus does not know whether the linear scan extends the full length of the symbol or is tilted with respect to the symbol.

In another advantageous embodiment, the aiming light mechanism directs a pair of aiming lights to each symbol, which illuminates a pair of generally circular spot areas within the field of view and spaced along the field of view. To do. The two spot areas are preferably located at or near the end of the linear scan and remain fixed or stationary during the scanning of the symbol so that the user can close them both before and during the scan. Not only can both in and far out symbols be seen and searched, but they can also be tracked during scanning. However, one of the drawbacks associated with such stationary paired light aiming is the need for two aiming light sources and associated optics, which results in system complexity, weight, size and cost. Is to increase.

In yet another advantageous embodiment, the aiming light mechanism is a single reciprocating oscillating focusing mirror operative to cause the aiming light to sweep each symbol and illuminate a line region extending along the field of view onto the symbol. Aim the aiming light. Such dynamic single-light aiming has the advantage that it is easier to see, locate, and track the close-in symbol compared to static aiming. .
However, one of the drawbacks of such dynamic aiming is
The intensity of the light collected by the human eye is inherently reduced, so when the focusing mirror is swept at a high scan rate, such as 40 scans per second, one can see and position the far out symbol, It is not easy to keep track of.

In yet another advantageous embodiment, the aiming light mechanism directs a single aiming light onto a focusing mirror having a stationary state and a reciprocating oscillatory state. Initially, the aiming light is reflected from a stationary focusing mirror to each symbol, illuminating a spot area within the field of view, preferably near the center of the symbol, to locate the symbol prior to scanning the symbol. The focusing mirror is then oscillated back and forth, reflecting the aiming light at the symbol, the aiming light sweeps through the symbol and illuminates a line area extending along the field of view on the symbol,
It is designed to keep track of the symbols. The reason why such a combination of static and dynamic aiming is so desirable is that it allows the user to track the close-in symbol during the scan (which is not possible with static single light aiming alone). (It is not easy.) Moreover, the user can at least locate the far-out symbol before scanning (this is not easy with dynamic aiming alone). In most cases, the symbol read is a closed-in symbol, so it is not important that the far-out symbol cannot be tracked in the combined static and dynamic aiming embodiment.

In order to realize such a combination of static and dynamic aiming, the triggering device comprises a plurality of switching positions, directly on the aiming light source and the vibrating focusing mirror,
Alternatively, it is advantageously operatively connected indirectly via a decoding / control device. In the first position, i.e. in the off state of the trigger device, all parts in the head are deactivated. In the second position, the first operating state, the aiming light source is activated and the focusing mirror is placed in a predetermined fixed position, for example a central position, for a predetermined time and the aiming light source illuminates a central spot area of the symbol to be read. To be done. In the third position, the second operating state,
All other components in the head are activated, including the component for the reciprocating oscillation of the focusing mirror, which initiates the reading of the symbol and the illumination of the line area along the field of view.

All of the embodiments of the aiming light mechanism described above are of a type that is manually placed on the symbol or at a slight distance from the symbol and then manually dragged and moved across the symbol. This is in stark contrast to the aiming light mechanism provided in the rod-shaped or pen-shaped readers of. In the latter case,
Manipulation of the pen's angle with respect to the symbol, pen speed, uniformity of pen speed, and other factors had to be rigorous, requiring the skilled user to perform the aforementioned exercises. In any case, the manual reader could only scan at most once per manual movement and the user had to repeat the manual scan many times if the symbol was not successfully read on the first attempt.

Another feature of the present invention is a novel optics for focusing highly divergent, radially asymmetric laser diode light having a generally elliptical optical cross section.
The optical device preferably comprises a focusing lens, for example a plano-convex lens, and an aperture stop located in the first optical path in the vicinity of the focusing lens. This aperture stop has a circular, rectangular or elliptical shape smaller than the cross-sectional area of the light at the position of the aperture stop so that part of the incident laser diode light can pass through the aperture stop on the way to the symbol. It may have a cross section. The walls that bound the aperture stop prevent and block the rest of the incident laser diode light from passing through the aperture stop on its way to the symbol. Such an aperture stop for light is conventionally known, such as disclosed in U.S. Pat. In stark contrast to the design. With such an aperture stop of light, the numerical value of the aperture is reduced from a large value of 0.15 to 0.45 to a value of 0.05, and the optical magnification is greatly reduced, thereby achieving the above-mentioned advantages. Only a single focusing lens needs to be used for this. Although such an aperture stop of the light weakens the output of the laser diode, the advantages achieved are well worth the cost, and the fraction of the incident laser diode light that passes through the aperture stop to read the symbol. Sufficient output remains.

While the use of aperture stops is known in optical systems, it is believed that such apertures of light are new and not trivial in laser scanning systems for reading symbols. .. As aforementioned,
While the aperture stop reduces the power of the portion of the incident laser diode light that impinges on the symbol, laser scanning system designers generally consider that the power of the light, and in particular the portion of the incident light that impinges on and scans the symbol. You don't want to knowingly throw away power. This is because the power contained in the laser beam that is reflected and condensed from the symbol is weakened thereby.

Furthermore, the cross-sectional area of the incident laser diode light,
That is, it is well known that for a given spot size, the depth of focus of an optical system with an aperture stop will be less than the depth of focus of an optical system without an aperture stop. In general, laser scanning system designers want to make the depth of focus as large as possible (and thus the effective distance as large as possible), so the use of aperture stops should be avoided.

Further, in an optical system having an aperture stop,
It is also known that the theoretical minimum laser light spot size is larger than in an optical system without an aperture stop. Therefore, in applications where a very small spot size is needed, one might not want to use an aperture stop.

In an optical laser system having no aperture stop, the cross section of the laser light spot has a Gaussian brightness distribution characteristic. In contrast, when an aperture stop is used, diffraction of the light causes halos or streaks in the beam spot. Such halos and stripes effectively increase the size of the beam spot, and have other adverse effects. The undesired enlargement of the beam spot size is another reason why aperture stops are not used in laser scanning systems.

From this point of view, the use of an aperture stop implies the use of complex mathematics according to basic diffraction theory to design an optical system. Since laser scanning system designers often use Gaussian light mathematics, which is simpler than diffraction mathematics, that is another reason why the use of an aperture stop in a laser scanning system has never been proposed. Conceivable.

A so-called "cold mirror" is used to reflect the visible aiming light to the collector mirror of the sensor, but the reflected laser diode light reflected from the symbol and collected by the collector mirror is said cold mirror. The transmission of a light reflection optical path assembly is particularly compact. Yet another useful aspect of the integrated optics assembly is to integrate a collection mirror for the reflected laser light into a monolithic multi-purpose mirror with the aforementioned scanning mirror for the incident laser diode light and the aforementioned focusing mirror for the aiming light. It is to be.

Alternatively, the optical assembly may include a fixed reflecting / collecting mirror combination assembly and a simple, lightweight, reciprocating scan mirror. Such an optical assembly provides flexibility in mounting various components within the scan head, and because the scan mirror is lightweight, it provides improved control over the laser beam scan pattern. The use of a lightweight scan mirror further reduces wear on the scan motor attached to the scan mirror, thus extending motor life.

Another highly desirable feature is the interchangeable design of the head components so that the manufacturer can easily adapt the head to the particular requirements of each user. That is, different parts can be housed in a single handle for the head, or multiple replaceable handles for the head, which allows the head to be easily adapted to the needs of the user and the conventional labor required. It is not necessary to manufacture such a custom-made head.

Yet another advantageous feature is that the head does not need to be fitted with discrete windows, such windows can come off the mount and expose the interior of the head to moisture, dust and other contaminants. Therefore, under certain conditions, the possibility of adversely affecting the operation of the head is prevented. For this purpose, at least a part of the head is made of an integral light-shielding material structure, and a cover of light-shielding material is provided on the transparent portion of the head to prevent light from passing therethrough. The other transparent portion is left uncovered and is configured to perform the function of the window described above.

Further, in order to obtain the impact strength of the head, it is preferable that the cover is formed of a thick shock absorbing material such as rubber.

[0048]

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

Referring to FIGS. 1-8, reference numeral 10 is lightweight (less than 1 pound), narrow body, streamlined, narrow pointed, handy, fully portable, easy to operate,
A generic term for laser scanning heads that do not fatigue the arms or elbows, which heads can be held entirely by the user for use in a laser scanning system for reading, scanning, and analyzing symbols. The user can aim the scanning head at each symbol before and during reading of the symbol, with the fold of the scanning head. The term "symbol" is intended to encompass a mark made up of different parts having different light reflection properties at the wavelength of the light source utilized, eg the laser. This mark may be, for example, the above-mentioned black and white industrial symbol such as code 39, coder bar, interleaved 2 of 5, or the like. Alternatively, it may be an ubiquitous UPC bar code symbol. The mark may also be an alphabet and / or a number. The term "symbol" also includes a mark arranged on the background screen, in which case the mark or at least part of it has a light reflection characteristic different from that of the background screen. In this latter definition,
The "reading" of symbols is particularly useful in the field of robotics and object recognition.

As shown in FIGS. 1 to 3, the head 10 has a substantially rectangular cross section, a handle portion 12 extending substantially vertically along the handle axis, and a narrow body tube extending substantially horizontally.
That is, a substantially gun-shaped housing having a body portion 14 is provided. The cross-sectional dimensions and overall size of the handle portion 12 are such that the head 10 conveniently fits and remains in the user's hand. The body and handle are made of a lightweight, resilient, impact-resistant, self-supporting material, such as a synthetic plastic material. The plastic housing is preferably injection molded, but may be vacuum molded or blow molded with a volume of about 50.
A thin, hollow shell is formed that bounds an interior space that is less than a cubic inch, and sometimes less than about 25 cubic inches. Such a specific numerical value is not a limitation and is a standard for estimating the overall maximum size of the head 10.

In the use position as shown in FIGS. 1 to 3, the body portion 14 narrows forward with the upper front wall 16 toward each other, and joins at the nose portion 20 at the frontmost portion of the head. It has a main part with a wall 18. The body portion 14 further includes a rear region behind the front walls 16 and 18 having a rear wall 22 spaced therefrom. The body portion 14 further includes a top wall 24, a bottom wall 26 below the top wall 24, and opposite side walls 2 located parallel to each other between the top wall 24 and the bottom wall 26.
It has 8 and 30.

The handle portion 12 and the body portion 14 merge,
A manually operated, preferably push-button, trigger for pivoting about a pivot axis 34 in a forward-facing area of the head, which is normally hit by the user's four fingers when in the use position. A switch 32 is attached. The bottom wall 26 has a tubular neck 36 which extends downwardly along the handle axis and which extends radially inwardly into a generally rectangular collar 38.
Ends with. The neck 36 and collar 38 have forward facing slots through which the trigger switch 32 projects and travels.

The handle portion 12 has an upper flange portion 40 of substantially rectangular cross section that extends radially outward, and this flange portion 40 also has a forward facing slot through which the trigger switch 32 projects and moves. is doing. The upper flange portion 40 is elastic and can bend radially inward. When the upper flange portion 40 is inserted into the neck portion 36, the upper flange portion 40 is carried by the collar portion 38, and is bent inward in the radial direction until the flange portion 40 crosses the collar portion 38, at which point the upper flange portion 40 is unique. The elasticity of the element causes it to snap back to its initial undeflected position and engage behind the collar 38 with a snap-on locking action. To disengage the handle portion 12 from the body portion 14, the upper portion of the handle portion 12 flexes sufficiently until the upper flange portion 40 again crosses the collar portion 38, whereupon the handle portion 12 can be withdrawn from the neck portion 36. In this way, the handle portion 12 can be snapped on and removed from the body portion 14 in a freely attachable / detachable manner, and as will be described later, each of the replaceable handle portions containing different parts of the laser scanning system is a separate handle. The parts are mounted on the body part so that the head 10 can be adapted to different requirements of the user.

A plurality of components are mounted on the head 10, and at least some of them are activated by a trigger switch 32 directly or indirectly by using a control microprocessor, as will be described later. One of the head components is an activatable laser light source (see FIG. 4), which is a semiconductor laser diode 42 that operates to propagate and generate incident laser diode light when activated by a trigger switch 32, for example. is there. As described above, this laser light is “invisible” to the user, or is not easily visually recognizable, has high divergence, is asymmetric in the radial direction, has a substantially elliptical cross section, and has a wavelength of It is about 7,000, for example 7800 angstroms. Advantageously, diode 42 is commercially available from many manufacturers, an example of which is Model N from Sharp Corporation.
O. It is LT020MC. The diode may be of continuous wave type or pulse type. It suffices to supply a low voltage (for example, DC 12 V or less) to the diode 42, and a battery (DC) power source housed in the head
Or in a replaceable battery pack accessory 44 (see FIG. 7) removably mounted in the head, or in a cable 46 (see FIG. 2) connected to the head from an external power source (eg, DC power source). Power leads can be used.

As shown in most detail in FIG. 4, the laser diode 42 is mounted on a printed wiring board 48. The optical assembly is mounted within the head and is adjustably disposed with respect to the diode 42 to optically correct the incident laser light and along the first optical path of the nose portion 20 outside the head. It is arranged to direct the incident laser light in the direction of a reference plane which is arranged in front and which is located substantially perpendicular to the longitudinal direction along which the incident laser light propagates. The symbol to be read is near the reference plane, that is, either on the reference plane itself, on one side thereof, or on the other side thereof, that is, at a position either within the focal depth or the depth of field of the optically modified incident laser light. The depth of focus or the depth of field is also called the effective distance at which the symbol can be read. The incident laser light is reflected in many directions from the symbol, and the portion of the reflected laser light that travels from the symbol to the head again along the second optical path is called a return portion, which of course is visually easy for the user. I can't recognize it.

As most clearly shown in FIG.
The optical assembly is provided with an elongated cylindrical optical tube 50, and in an area of one end of the optical tube 50, an annular casing portion of a laser diode 42 is exactly received to hold the laser diode 42 in a fixed position. 52
And a lens barrel 54 is provided at the other end of the optical tube 50 so as to be vertically movable. The lens barrel 54 includes an aperture stop 56, a blocking wall portion 58 that surrounds the aperture stop 56 and forms a boundary between the aperture stop 56 and a cylindrical side wall portion 60 that forms a boundary between internal spaces.

The optical assembly is further provided with a focusing lens 62, for example, a plano-convex lens, which is arranged in the inner space of the side wall portion 60 in the first optical path and performs an operation of focusing the incident laser light on the reference plane. The aperture stop 56 may be arranged on either side of the focusing lens 62, but is preferably on the downstream side. A bias device, that is, an elastic coil spring 64 is arranged in the optical tube 50. One end of the coil spring 64 is carried by the casing of the laser diode 42, and the other end is carried by the flat side of the focusing lens 62. The coil spring 64 constantly presses the focusing lens 62 against the blocking wall 58, thereby fixedly positioning the focusing lens 62 with respect to the aperture stop 56. The focusing lens 62 and the aperture stop 56 are moved in conjunction with each other when the lens barrel 54 moves in the vertical direction. The side wall portion 60 is initially received in a threaded or sliding manner on the inner peripheral wall forming the boundary of the optical tube 50, on the one hand, between the focusing lens 62 and the aperture stop 56,
On the other hand, once the desired longitudinal spacing with the laser diode 42 has been adjusted, it is fixed to the inner wall of the optical tube 50, for example by gluing or screwing. The vertical movement of the side wall portion 60 and the inner peripheral wall of the optical tube 50 is a means for adjusting the focusing lens 62 and the aperture stop 56 so that the focusing lens 62 and the aperture stop 56 are fixed to the laser diode 42. This is means for fixedly positioning the focusing lens 62 and the aperture stop 56 at a predetermined distance from the laser diode 42.

Since the cross-sectional area of the aperture stop 56 is smaller than the cross-sectional area of the incident laser light at the portion of the aperture stop 56, only a part of the incident laser light is downstream along the first optical path while proceeding to the symbol. Can pass through the aperture stop 56. The blocking wall 58 blocks the remaining portion of the incident laser light and blocks the remaining portion from passing through the aperture stop 56.
The cross section of the aperture stop 56 is preferably circular for ease of manufacture, but may be rectangular or elliptical, in this case to transfer more energy to the symbol,
A rectangular or elliptical strip is aligned with the larger divergence angle of the incident laser light.

According to the law of diffractive optics, the size of the required cross section of the incident light on the reference plane depends on the size of the aperture stop 56, the wavelength of the incident light, and the vertical distance between the focusing lens 62 and the reference plane. Determined. Therefore, assuming that the wavelength and the vertical interval remain the same, the cross-sectional area of the light on the reference plane can be easily controlled by controlling the cross-sectional area of the aperture stop 56. Further aperture stop 5
By arranging 6 downstream of focusing lens 62 rather than upstream, it is not necessary to consider tolerances of focusing lens 62 when determining the cross-sectional area of light at the reference plane.

Since the aperture stop 56 is arranged at the center of the laser diode light, the light intensity is substantially uniform at the pn junction of the laser diode 42, that is, both the surface vertical to the emitter and the surface horizontal. Note that the laser diode light is not symmetrical in the radial direction, so the brightness of the light in the plane perpendicular to the pn junction is strongest at the center of the light and decreases from there toward the radially outward direction. I want to be done. The same applies to the plane parallel to the pn junction, but the rate of decrease in brightness is different. Therefore, a small opening, preferably circular, is elliptical,
By placing it in the center of the laser diode light, which has a larger cross-sectional area, the elliptical cross-section of the light is modified to be nearly circular at the aperture, and in both the plane perpendicular to the pn junction and the plane horizontal. The light intensity is almost constant. The aperture stop 56 preferably reduces the numerical aperture of the optics assembly to below 0.05, allowing a single focusing lens 62 to focus the laser light at the reference plane.

In the preferred embodiment, the laser diode 4
The approximate distance between the second emitter and the aperture stop 56 is about 9.7.
mm to about 9.9 mm. The focal length of focusing lens 62 is in the range of about 9.5 mm to 9.7 mm. If the aperture stop 56 is rectangular, its dimensions are approximately 1 mm x 2
mm. The cross section of the light is about 3.0 mm × about 9.3 mm just before the light passes through the aperture stop 56. These distances and dimensions are merely examples, which allows the optical assembly to modify the laser diode light and provide a cross section of about 6 mils to about 12 mils at a reference plane about 3 inches to about 4 inches away from the nose portion 20. It is possible to focus the light to have. The effective distance is such that the close-in symbol can be placed anywhere from about 1 inch away from the nose portion 20 to the reference plane, and the far-out symbol can be located about 20 inches away from the reference plane. It can be placed anywhere from the to the reference plane.

The portion of the incident laser light that passes through the aperture stop 56 is converted by the optical assembly into the optical axis 102 in the head 10.
Along the back is directed to a substantially flat scanning mirror 66, where it is reflected. The scanning mirror 66 forwards the laser light impinging on the scanning mirror 66 along the optical axis 104 to the upper front wall 6.
A forward-looking window 68 mounted on 8 for transmitting laser light
Through to the sign. As is clearly shown in FIG. 9, a representative symbol 100 is illustrated near the reference plane, which, if it is a bar code symbol, consists of a series of vertical bars spaced from each other along the length. Made of Reference numeral 106 indicates a substantially circular, invisible laser spot for the symbol. The laser spot 106 in FIG. 9 is an instantaneous position. Because, as will be described later, the scanning mirror 66, when actuated by the trigger switch 32, repeatedly performs a lateral reciprocating oscillatory motion,
This is because the incident laser light is swept in the longitudinal direction across all bars of the symbol in a linear scan. The laser spots 106a and 106b in FIG. 9 indicate the instantaneous end positions of the linear scanning. The linear scan can be done at any position along the height of the bars provided that all bars are swept. The length of the linear scan area is longer than the length of the longest symbol expected to be read, and in the preferred example the area of the linear scan is 5 inches long in the reference plane.

The scanning mirror 66 is mounted on the scanning device,
This is preferably a high speed scan motor 70 of the type illustrated and described in U.S. Pat. No. 4,387,397, the entire contents of which are referenced in this application. For the purposes of this application, the scan motor 70 includes an output shaft 7 having a support bracket 74 fixedly attached thereto.
It would be sufficient to point out that it has 2. Scanning mirror 66 is fixedly mounted on support bracket 74. The high-speed scanning motor 70 oscillates the output shaft 72 in a circumferential direction alternately and reciprocally and repeatedly at a vibration speed of a plurality of times per second by an arc length of any desired size, typically 360 degrees. To be driven. In the preferred embodiment, the scanning mirror 66 and the output shaft 72 oscillate in conjunction,
The scanning mirror 66 has an angular spacing of about 32 degrees in the reference plane, that is, over the arc length, and 20 scans per second or 40.
The incident laser diode light striking the scanning mirror 66 is repeatedly swept at the rate of oscillation.

Referring again to FIG. 2, the light intensity of the returning portion of the reflected laser light is variable on the symbol during scanning because the light reflection characteristics of the various parts constituting the symbol 100 are different. The return portion of the reflected laser light is collected by a substantially concave, spherical collector mirror 76, by the upper and lower demarcation lines 108, 110 as shown in FIG. 2 and as shown in FIG. Boundary lines 112 and 114 on the opposite side
Is a conical light stream within a conical collection volume bounded by. The condensing mirror 76 reflects the condensed conical light along the second optical path to the sensor, for example, the photosensor 80, through the laser light transmitting element 78 and along the optical axis into the head. The focused conical laser light that is directed to the photosensor 80 has upper and lower boundary lines 118, 120.
(See FIG. 2), and opposite boundaries 122,124.
The boundaries are defined by (see FIG. 3). The photosensor 80, which is preferably a photodiode, detects the variable brightness of the focused laser light along a linear scanning region, preferably over a field of view extending beyond that region, and the detected variable light intensity. To generate an analog electrical signal.

Referring again to FIG. 9, reference numeral 126 designates an instantaneous collection zone for symbol 100, from which the instantaneous laser spot 106 is reflected. In other words, photosensor 80 sees collection zone 126 when laser spot 106 strikes symbol 100. When the collecting mirror 76 is mounted on the support bracket 74 and the scanning mirror 70 is activated by the trigger switch 32, the collecting mirror 76 reciprocally and repeatedly oscillates in the lateral direction,
The longitudinal field of view of the photodiode is swept across the symbol in the linear scan area. Focusing zones 126a, 126
b indicates the instantaneous end position of the linear scanning of the visual field.

The scanning mirror 66 and the condenser mirror 76 have an integrated structure in the preferred embodiment. As shown in FIG. 8, a plano-convex lens 82 made of a light transmissive material, preferably glass, is provided with a light reflecting layer or a coating. It was done. Plano-convex lens 8
2 has a first substantially flat outer surface in the portion coated with the first light-reflecting layer, which forms a flat scanning mirror 66, and a second portion in the portion coated with the second light-reflecting layer. It has two second substantially spherical outer surfaces, which form a concave collecting mirror 76, such as a so-called "second surface spherical mirror".

The scanning mirror 66 is of a discrete type and has a front surface.
It may also be a discrete, miniature flat mirror that is glued or molded into place on the silver-plated concave mirror at an appropriate position and angle.
As will be described below, the concave condenser mirror 76 not only has a function of condensing the returning portion of the laser light and condensing it on the photodiode 80, but also directs the aiming light to the outside of the head and condenses it there. It also functions.

A pair of or more printed wiring boards 84 and 86 are mounted in the head, and various secondary electric circuits are mounted thereon. For example, the signal processing device having the components 81, 82 and 83 on the substrate 84 is the sensor 8
It operates to process the analog electrical signal generated by the 0 and produce a digitized video signal.
The data that describes the symbol can be derived from the video signal. A suitable signal processor for this purpose is described in U.S. Pat. No. 4,251,798. The components 87,89 on the substrate 86 constitute the drive circuit for the scan motor 70, and a suitable motor drive circuit for this purpose is described in U.S. Pat. No. 4,387,297. The component 93 on the substrate 48 on which the laser diode 42 and the sensor 80 are mounted is a voltage converter for converting the input voltage into a voltage suitable for energizing the laser diode 42.
For details of this voltage converter, see, for example, U.S. Pat.
See 251,798 and 4,387,297.

The digitized video signals are connected by an electrical coupling consisting of a socket 88 provided on the body part 14 and a matching plug 90 provided on the handle part 12. When the handle portion 12 is attached to the body portion 14, the plug 90 is automatically electromechanically socket 88.
Conforms to. The handle portion 12 further includes a pair of circuit boards 9
2, 94 (see FIG. 1) are mounted and various parts are mounted thereon. For example, a decoding / control device consisting of components 95, 97 serves to decode a digitized video signal into a digitized decoded signal from which desired data describing symbols according to a software control program. Is obtained.
The decoding / control device is a PRO that holds the control program.
M, a RAM for temporarily storing data, and a control microprocessor for controlling the PROM and RAM. The decoding / control unit determines that the decoding of the symbol has been successfully achieved, and terminates the reading of the symbol when the symbol has been successfully decoded. The reading is started by pressing the trigger switch 32. Decode /
The controller also controls the actuating components in the head that are triggered by the trigger switch 32, and also automatically terminates the reading to the user, for example by sending a control signal to the pilot lamp 96 to light the lamp. It also has a control circuit for notifying that.

The decoded signal, in one embodiment, is transmitted via a signal conductor in cable 46 to a remote host computer 258, which in turn transmits the signal to host computer 25.
8 basically acts as a large database, stores the decoded signal and possibly provides information about the decoded signal. For example, the host computer 25
8 can provide retail price information corresponding to the object identified by the decoded symbol.

In another embodiment, a local data storage device, such as component 95, is mounted on handle 12,
Store a plurality of read decoded signals. The stored decoded signal can be unloaded to a remote host computer. By providing local data storage, there is no need to use the cable 46 during reading of symbols, which is highly desirable to operate the head 10 as freely as possible.

As described above, the handle portion 12 may be one of a set of a plurality of handles which can be exchangeably attached to the body portion 14. In one embodiment, the handle portion 12 is left empty, in which case the video signal may be
Transmitted via cable 46 for decoding by the controller. In another embodiment, only the decoding / control device may be implemented in the handle portion 12, in which case the decoded signal is transmitted via cable 46 for storage in a remote host computer. In yet another embodiment, the decoding / control device and local data storage device can be housed within the handle portion 12, in which case the stored signals decoded by multiple reads are stored on a remote host computer. It can be unloaded and the cable 46 is only connected to unload the stored signal.

Alternatively, rather than having a set of removable handles, a single handle may be permanently fixed to the head, in which case the removable handle end 128 may be removed and replaced. This allows different components to be mounted on removable circuit boards 92, 94, which are optionally included in a single handle.

To power the laser diode 42 and the various components in the head 10 that require power, a voltage signal is transmitted through the power conductors in the cable 46 to bring the input voltage signal to the required voltage value. A converter, such as component 93, can be used to convert. In the embodiment where the cable 46 is not used during reading of the symbol, the rechargeable battery pack assembly 44 (see FIG. 7) is removably snapped onto the bottom of the handle portion 12.

Further in accordance with the present invention, an aiming light mechanism is implemented in the head, particularly in the aforementioned situation where the laser light incident on the symbol and reflected from the symbol is not easily visually recognizable to the user. It is designed to assist the user in visually searching for each symbol to be read and aiming the head there. The aiming light mechanism is mounted in the head and includes an activatable aiming light source 130 operatively connected to the trigger switch 32, such as a visible light emitting diode (LED), an incandescent white light source, a xenon flash tube, and the like. When activated directly by the trigger switch 32 or indirectly by the decoding / control device, the aiming light source 130 propagates and produces diverging aiming light. This light is visible to the user and its wavelength is about 6600 Angstroms, so the color of the aiming light is almost red, contrasting with the white light surrounding the environment in which the symbol is located.

The aiming mechanism is further implemented in the head 10 for directing aiming light from the aiming light source along the aiming light path to the reference surface and each symbol and for illuminating at least a portion of each symbol visibly. ing. More specifically, as best shown in FIGS. 2 and 3, the aiming light (LED) 130 provides a substantially conical aiming light to the optical element 78.
Mounted on a sloping support 132 for facing towards. The conical aiming light, on its way to the optical element 78, has upper and lower boundary lines 134, 136 (see FIG. 2) and opposite boundary lines 138, 140 (see FIG. 3).
Is bounded by. As described above, the laser light focused by the optical element 78 is emitted from the photo sensor 80.
Filter to prevent ambient light noise from reaching the photosensor 80.
The optical element 78 also reflects the aiming light striking the optical element. The optical element 78 is actually a so-called cold mirror, which reflects light in the wavelength range of the aiming light but allows light in the wavelength range of the laser light to pass through. The aiming light is reflected from the cold mirror 78 along the optical axis of the laser light focused between the condenser mirror (concave mirror) 76 and the photo sensor 80 on the substantially same line as the optical axis 116 and collides with the concave mirror 76. To do. The concave mirror 76 collects the aiming light, and the concave mirror 76
And the symbol 100, the aiming light is reflected along the optical axis substantially on the same straight line as the same optical axis of the laser light condensed. Concave mirror 76 that functions as a focusing mirror for aiming light
Is about 8 inches to 10 from the nose portion 20 of the head 10.
At a distance of one inch, the aiming light is focused to a circular spot size of about 1/2 inch. Since the optical path part of the aiming light located outside the head 10 coincides with the optical path part of the focused laser light located outside the head, from the part of the symbol irradiated by the aiming light, that is, made visible. It can be said that the photosensor 80 sees the reflected laser light that is not easily visually recognizable.
In another modification, the cold mirror is arranged in the first optical path,
Aim the aiming light at the cold mirror so that the optical axis of the aiming light coincides with the optical axis of the output incident laser light, thereby directing the aiming light at the symbol to match the output incident laser light. You may do it.

As shown in FIG. 10, the LED 13 for aiming
In the first static single-light aiming embodiment, 0 is arranged relative to a fixed optical element (for example, a focusing lens) 142 fixedly arranged in the aiming optical path in the head. be able to. The focusing lens 142 serves to focus the aiming light onto the respective symbol 100 and direct the light there to illuminate a spot area 150 (see FIG. 11) on the symbol in the field of view. The spot area 150 is circular near the center of the symbol and is preferably illuminated both during the search for the symbol before scanning and during the scanning of the symbol reading.
The static single-light aiming embodiment shown in FIG. 10 allows both close-in and far-out symbols to be searched and viewed, with the far-out symbol being far from the head. So it is only illuminated at a lower intensity, but still visible to the user. However, as described above, the fixed spot area 1
The 50 does not help much in tracking the scan across the symbol.

Next, referring to FIG. 12, a second static pair of light aiming embodiments will be described. A focusing lens having a pair of aiming LEDs 130a and 130b, which are the same as the aiming LED 130, is fixed. It is arranged at an angle with respect to 142, and the focusing lens 142 includes LEDs 130a, 130
Both aiming lights of b are directed to the same respective symbol and illuminated such that a pair of spot areas 152, 154 in the field of view on these symbols and linearly spaced from each other along the field of view are visible. Fulfill the function of Spot area 15
2, 154 and a circle near the end of the scanning area, illuminated so that the symbol can be searched for and tracked both before and during the reading of each symbol, both before and during scanning. Is preferred. The static pair of light aiming embodiment shown in FIG.
Both far-out symbols can be searched and viewed, and the far-out symbols are illuminated at a lower intensity because they are far from the head, but still visible to the user. As mentioned above, the pair of fixed spots 152, 154 is a useful aid in tracking the scan across the symbol.

A third dynamic single-light aiming embodiment will now be described with reference to FIG. In this case, instead of fixedly mounting the lens 142 in the head,
The lens 142 is oscillated in the manner described above for the scanning / focusing / focusing components to sweep the aiming light across each symbol, and a line region 156 extending along the field of view over the symbol (FIG. 13).
). Line area 156 is illuminated during the scan to track the symbol during the reading of each symbol. The close-in symbol is well illuminated even when scanning is performed at speeds of 40 scans per second or more. However, in the case of the far-out symbol, the distance from the head is large,
Line area 156 is less visible because of the faster scanning speed.

Returning to FIG. 1 to FIG. 6, the trigger switch 32
Statically activated in various positions or states by
A dynamic combination aiming mechanism is illustrated. In Figure 2,
The trigger switch 32 is in the off state, and in this case, all the activatable components in the head 10 are mounted with the pair of electric switches 58 and 160 on the lower side of the circuit board 84.
The electrical switches 58, 160 each have spring-loaded contacts or buttons 162, 164 which extend to the outside of the switch in the off state and are carried in the region of opposite ends of the lever 166. The lever 166 is adapted to pivot in a position offset from the center of the pivot shaft 168 on the rear extension 170 of the trigger switch 32.

When the trigger switch 32 is first pushed to the first initial range as shown in FIG. 5, the lever 166 pushes only the button 162, and the pushed switch 158 is in the first operating state, where the trigger is triggered. The switch 32 activates the aiming light 130, which is reflected back from the cold mirror 78 and forward from the focusing mirror 76 to the symbol. In the first operating state, the trigger switch 32
Places the condenser mirror 76 at a predetermined fixed position. A stationary collection mirror 76 directs aiming light at the symbol prior to scanning to assist the user in searching for the symbol prior to reading the symbol and spot in the same field of view as the central spot area 150 of FIG. Illuminate on the symbol so that the area is visible. The fixed positioning of the condenser mirror 76 energizes the DC winding of the scanning motor 70 so that the output shaft mounted thereon and the condenser mirror 76 are angularly rotated to the central reference position. This is preferably achieved.

Then, when the trigger switch 32 is pushed to the second larger range shown in FIG. 6, the lever 166 pushes not only the button 162 but also the button 164, so that the second operation state is set. In the second operating state, the trigger switch 32 causes all of the remaining activatable components in the head 10, such as the laser diode 42 and the collection mirror 7 to be activated.
Scan motor 70 for vibrating 6 and photodiode 8
0, the signal processing circuit and other circuits in the head are activated to start reading the symbol. Since the collector mirror 76 is oscillated rather than fixed, the aiming light is dynamically swept across the symbol, identical to the line area 156 of FIG.
Illuminate the line area extending along the field of view so that it is visible. Thus, it assists the user in tracking the symbol while reading it during scanning. Tracking such a symbol makes it very clearly visible for closed-in symbols, but less so for far-out symbols.

The aforementioned continuous activation of the components within the head 10 can also be effected by a single two-pole switch with built-in continuous contacts.

Returning to FIG. 1, it can be seen that many of the various components in the head are mounted so as to be buffered by the front impact blocking member 172. The circuit board 48 and all the components thereon are supported on the blocking member, and a rear impact blocking member 174 is also provided. The scanning motor 70 and the aiming lamp 130 are supported on the blocking member. A supporting plate 176 is carried. The light deflector 178 partitions the interior of the body and assists the cold mirror 78 in preventing stray ambient light from reaching the photosensor 80.

The laser scanning head of FIG. 2 is a return reflection type scanning head which scans the output incident laser light and the field of view of the sensor. It is needless to say that the present embodiment is not limited to this, and other modified examples can be applied. For example, while the field of view is not scanned, the incident laser light output is directed at a symbol through one window in the head and swept across the symbol, and the returning laser light is focused through another window in the head. Forms are also possible, in which the output incident light is directed onto the symbol during scanning of the field of view, but without sweeping across the symbol.

Instead of the housing shown in the drawings, various housing types can be used in consideration of aesthetics, environment of use, size, selection and arrangement of electronic and mechanical parts, necessary cushioning inside and outside the housing, and the like.

The laser scanning head of the present invention need not be portable, but may be a desktop freestanding workstation, in which case the symbol is preferably an overhead window through which the outgoing incident laser light is directed, or Pass the workstation under the port. Although the workstation itself is fixed, at least during the scanning of the symbol, the symbol is movable relative to the workstation and must be aligned with the output light, for this purpose the present embodiment The aiming light mechanism of is particularly advantageous.

The laser scanning head of the present invention provides high density, medium density and low density within the approximate effective distance range of 1 inch to 6 inches, 1 inch to 12 inches and 1 inch to 20 inches, respectively. Each bar code symbol can be read. The high density, medium density and low density bar code symbols referred to herein have minimum widths of 7.5 mils, 15-20 mils and 30 mils, respectively.
Symbols with bars and spaces that are ~ 40 mils. In the preferred embodiment, for symbols of known density, the position of the reference plane can be optimized for the maximum effective distance of the symbol. In addition to the aiming light mechanism of the previous embodiment, other means may be provided to assist the user in aiming the head at the symbol. For example, it is possible to allow the user to look into a protruding looking device that is formed on the upper part of the housing and extends along the first or second optical path. An observation port having a viewing window may be provided on the head to allow a user to look through the viewing window for a symbol in the window. An acoustic range finder can also be used to find the symbol. The rangefinder emits an acoustic signal, detects an echo signal, and activates an acoustic indicator in response to the detection. The audible indicator alerts the user that the symbol was found by emitting a sound or varying the speed of a series of sounds or acoustic signals.

In another aspect of the present invention, the aiming light spot on the above symbol, for example, to make it easier to see,
Or, it may be desirable to flash to save on the average power consumed by the aiming light source. Such flashing light spots can be implemented in electrical and / or mechanical devices.

FIG. 14 shows a preferred embodiment of the same type of laser scanning head as in FIG. For simplicity, the same parts in FIG. 14 have the same reference numbers as the corresponding parts in FIG.

Regarding the difference between FIG. 2 and FIG. 14, FIG.
One important difference of the head 10 'of the
4'consists of two housing parts, an upper housing 180 and a lower housing 182, which are preferably snap-fit and assembled together. The lower housing 182 is made of a light-shielding opaque material such as a colored synthetic plastic material, while the upper housing 180 is made of a light-transmissive transparent synthetic plastic. Since both output light and input light can pass through the transparent upper housing 180, the window area 186
A cover 184 of light blocking material covers the entire outer surface of the transparent upper housing 180, except for the display area 188. The cover 184 is made of an injection-molded thermosetting rubber-like material, the inner surface of which is closely matched to the outer surface of the upper housing 180 so as to be in close contact with the entire outer surface of the upper housing and to be friction-bonded to the outer surface. Held in. The cover that fits perfectly is actually the window area 186 and the display area 18
All parts of the transparent upper housing 188 except 8 are shielded to prevent output light and input light from passing therethrough.

Thus, unlike the conventional head, it is not necessary to separately bond or attach the discrete window to the predetermined position of the head. Uncovered window area 186
Acts as a window for both output and input light. The uncovered window area 186 as well as the upper housing 180
Integrated with the rest of the head, so that the window is now disengaged from the mount and covered with dust, moisture, and other contaminants, preventing the proper operation of the optical and electrical components in the head. The risk of being lost.

Furthermore, since the display area 188 is not covered by the cover 184, the light from the display lamp 96 'can shine through the above area. Furthermore, since it is not necessary to attach a separate window in the area of the display lamp 96 'as in the conventional type, it is also useful for sealing the inside of the head extremely effectively.

The rubber-like cover is thick and has a cushioning effect.
It is preferably elastic and serves as a buffer for the head. Further from FIG. 14, the cover is shown in the upper and lower housings 18
It can be seen that the joint between 0 and 182 has a lower curved flange, which is a very effective gasket-like sealing means.

Another difference between the embodiments of FIGS. 2 and 14 is that the partition wall 190 for sealing is provided in the portion of the trigger switch 32 '. The sealing septum 190 has an actuator 192 in its center, one surface of which is in contact with the button 164 'of the switch 160'. The opposite surface of the actuator 192 is in contact with the indicator lamp portion 194 of the trigger switch 32 '. In operation, when the trigger switch 32 'is manually pushed, the indicator lamp section 194 forces the actuator 192 to push the button 16'.
The switch 160 'is activated by making contact with the switch 4'. During this operation, the iris 190 shields the inside of the head in the area of the trigger switch from the outside, thereby providing another entry point for contaminants such as dust and moisture that would otherwise be free to enter in the conventional case. Will be closed.

Another difference between the embodiments of FIGS. 2 and 14 is that the laser diode, the optical assembly, the aiming light source and the motor part of the scanning motor are all mounted in a common carrier part called the optical mount 200. It is that you are. Stand 2
00 has an upper part 202 and a lower part 204, which are assembled as follows. The upper end is 202 at the front end of the frame.
A projection 206 of the slab passes through a groove 208 formed in a conduit provided in the lower portion 204 and snaps behind the groove. On the back of the cradle 200, a threaded fastener 210 passes through a clearance hole in the lower portion 204 and threadably engages a threaded hole formed in the upper portion 202. The front cushioning member 172 'is disposed between the front face of the housing and the front face of the gantry 200, and the back cushioning member 174' is disposed on the gantry 200.
Is disposed between the back of the head and partitions 175, 177 provided on the back of the head and extending inward.

Still another difference is the printed wiring board 86 '.
Is not mounted above the printed wiring board 84 ', but is mounted in the rearwardly extending partition portion 212 formed between the partition portions 175 and 177 and the rear wall of the body portion 14'. ..

The other difference is that the handle fitting portion 12
8'is provided with a 0-ring sealing member mounted in an annular groove formed at the inner end of 8 '. It goes without saying that each of the above-mentioned members, and combinations of two or more thereof, can be usefully applied in different types of applications than the above-mentioned structure.

FIG. 15 shows yet another preferred embodiment of the optical system. The optical system of FIG. 15 can be incorporated into a scan head of the type of FIGS. 2 and 14 or a scan head of the type shown in FIG.

The optical system of FIG. 15 has a laser light source 216.
Is equipped with. The laser light source 216 comprises a helium-neon laser tube or laser diode that emits light that is visible or not easily perceptible as described above. The laser light source 216 can further include aiming optics that produce laser light as described above.

The optical system of FIG. 15 further includes a reflecting mirror 2
Eighteen. As shown in FIG. 15, the reflection mirror 2
18 can be fixed to the concave condenser mirror 220.
Alternatively, the reflection mirror 218 may be mounted on a support member in the scanning head as long as it is fixed in a stationary relationship with the concave condenser mirror 220. In any case, the reflection mirror 218
Scans incident laser light through a scanning mirror 232 as described below.
It is mounted at an appropriate angle so that it points toward.

The concave condenser mirror 220 is the support bracket 2
It is attached to 22. The laser light source 216 emits coherent aiming laser light toward the reflection mirror 218 along the first optical path 224. As described above, the incident laser light is emitted from the laser light source 216 along the first optical path to the mark 2
Proceed to 26. This first optical path is shown by a solid line with an arrow in FIG. The incident laser light is reflected at the mark 226, where the laser light follows a second optical path 230 shown by the set of dotted lines in FIG.
Return to 8.

The movable scanning mirror 232, which is lightweight, receives the incident laser light in the first optical path and reflects the laser light to the mark 226. The scanning mirror 232 further receives the reflected laser light along the second optical path reflected from the mark 226, and reflects this reflected laser light to the concave condenser mirror 220. The concave condenser mirror 220 is preferably a spherical concave mirror. The concave condenser mirror 220 receives the reflected laser light from the scanning mirror 232 and focuses the reflected laser light on the detector 228.

The scanning mirror 232 is mounted on the shaft 234 of a scanning motor (not shown). Scanning mirror 232
Is preferably reciprocally oscillated about the shaft 238 a plurality of times per second, typically at a rate of 40 scans per second, as indicated by arrow 236. Such reciprocal vibration of the scanning mirror 232 allows the laser light to scan the mark 226 in both directions. The axis 234 may simply rotate the scanning mirror 232 so that the laser light scans the mark 226 in one direction.

FIG. 16 shows the various components described above mounted on one type of scan head. Laser light source 216
Emits coherent aiming light along the first optical path 224. This light strikes the reflective mirror 218, which reflects the light to the scanning mirror 232. The scanning mirror 232 emits scanning light and directs the scanning light to the mark 226 (FIG. 1).
5). The mark 226 reflects the light whose brightness has changed to the scanning mirror 232 again. Scanning mirror 230 reflects the light to concave collection mirror 220, which reflects the light to photodetector 228. The photodetector 228 detects the varying intensity of the light and produces an analog electrical signal, which the scanning head processes in a conventional manner.

As shown in FIG. 16, the scanning head can operate completely independently of the power cord or the signal cord. In this way, the battery pack (not shown)
Powers all of the various components in the scan head.
The scan head also produces radio frequency (RF) signals that are transmitted to a host computer for further processing. The scan head can also include a receiver for receiving transmissions from the host computer to control various mechanisms of the scan head.

In the above embodiment, the case where the invention is applied to the portable laser diode scanning head has been described, but the invention is not limited to this, and the invention can be applied to a self-standing device such as a desktop work station. Needless to say.

[0108]

As described above, according to the present invention, the user can easily aim,
Even if the laser light from the semiconductor laser diode cannot be easily visually recognized by the user, the aiming can be simplified, and the reading efficiency and the reading time can be shortened.

[Brief description of drawings]

FIG. 1 is a front view of a portable laser diode scanning head according to the present invention.

FIG. 2 is an enlarged cross-sectional view taken along the line 2-2 of FIG.

FIG. 3 is a sectional view taken along line 3-3 of FIG.

4 is an enlarged sectional view taken along line 4-4 of FIG.

FIG. 5 is an enlarged detailed view showing a first operation state of the trigger switch assembly.

FIG. 6 is an enlarged detail view showing a second operating state of the trigger switch assembly.

7 is a configuration diagram of a detachable battery pack accessory of the head of FIG. 1. FIG.

8 is an enlarged cross-sectional view of the integral scanning / focusing / focusing mirror component taken along line 8-8 of FIG.

FIG. 9 is an enlarged view of a symbol and a part thereof where a laser beam impinges on and is reflected from the laser beam.

FIG. 10 is a schematic diagram of a static single aiming light mechanism.

FIG. 11 is an enlarged view of a symbol and part thereof illuminated by a static single or pair of aiming light mechanisms.

FIG. 12 is a schematic view of a pair of static aiming light mechanisms.

FIG. 13 is an enlarged view of a symbol and its portion illuminated by a single dynamic aiming light mechanism.

FIG. 14 is a diagram showing another preferred embodiment of the present invention.

FIG. 15 is a schematic illustration of another optical assembly useful in the present invention.

16 is a schematic diagram of a laser scanning head showing the arrangement of the optical assembly of FIG.

[Explanation of symbols]

 10 Laser Scanning Head 12 Handle Part 14 Body Part 20 Nose Part 32 Trigger Switch 36 Neck Part 42 Laser Diode 56 Aperture Stop 58,160 Electric Switch 62 Focusing Lens 64 Coil Spring 66 Scanning Mirror 74 Support Bracket 76 Condensing Mirror 80 Photo Sensor 100 Symbol 130 Aiming light source 216 Laser light source 218 Reflecting mirror 220 Concave converging mirror 224 First optical path 226 Mark 228 Photodetector 230 Second optical path 232 Scanning mirror 234 Axis 258 Host computer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mark Jay Crisshuber New York, USA 11788 Hauppauge Carlton Lane 26 (72) Inventor Boris Metricy New York, USA 11790 Stony Brook Millstream Lane 18 (72) Inventor Edward Barkhan New York, USA 11720 South Citicket 8th Street

Claims (20)

[Claims] 1. A laser scanning head for reading a symbol, comprising: (a) a startable laser light source mounted in the head and performing an operation to generate incident laser light when activated; A fixed reflection mirror for reflecting the incident laser light to a movable scanning mirror along one optical path, wherein the scanning mirror reflects the incident laser light in the direction of a reference surface located outside the head, and the reference surface. Is arranged so as to reflect to a symbol within an effective distance range in the vicinity of the symbol, and reflects the laser light reflected from the symbol, at least the returning portion of the reflected laser light is directed from the symbol to the head along the second optical path (C) a fixed concave condenser mirror, and (d) a head mounted inside the head, which moves the scanning mirror and indicates the incident laser light during scanning. Sweep across (E) a scan driving means for enabling the return portion of the reflected laser light to have a variable brightness over the scanning region, and A sensor for detecting a variable brightness of a returning portion of laser light and generating an analog electric signal indicating the detected variable light brightness, wherein the concave condenser mirror collects a returning portion of the laser light reflected over a visual field. A sensor of the type arranged to illuminate and direct a focused return to the sensor, and (f) mounted in the head to generate an analog electrical signal and generate a processed signal representing the symbol. Signal processing means for generating, (g) operatively connected to the scanning mirror, the laser light source, the scanning drive means, the sensor, and the signal processing means, and start these devices To do And a manually actuatable trigger means on the head adapted to initiate reading of a symbol when the user manually activates the trigger means. 2. The laser scanning head according to claim 1, wherein the incident laser light cannot be easily visually recognized by a user. 3. An optical component used in an optical scanning device having a light source and an optical sensor, which operates to read a symbol having portions having different light reflectances, wherein (a) the light from the light source is A fixed reflection mirror for reflecting light, and (b) a scanning mirror, which (i) reflects light from the reflection mirror to the mark portion while scanning across the mark portion, thereby changing the light intensity. A scanning mirror for reflecting at least a part of the light reflected from the mark portion and (ii) a reflected concave mirror, and a fixed concave condenser mirror mounted in a fixed relationship with the reflecting mirror. , The scanning mirror further functions to direct the light receiving portion of the light reflected from the mark portion to the condenser mirror, and the condenser mirror is arranged so as to focus the light from the scanning mirror on the detector. The mirror and (d) scan Optical component is characterized in that a moving means for moving the over. 4. The optical component according to claim 3, wherein the concave condenser mirror has an optical axis. 5. The optical component according to claim 3, wherein the light source is a laser light source, and the mark is a bar code symbol. 6. The optical component according to claim 5, wherein the laser light source emits light that cannot be easily visually recognized. 7. An optical component used in an optical scanning device, which has a laser light source and a laser light sensor mounted in a lightweight handy housing, and operates so as to read a mark having a portion having a different light reflectance. In (a) a fixed reflection mirror mounted in the optical path from the light source, and (b) light that reflects light from the reflection mirror to the mark part during scanning across the mark part and the light intensity is variable from the mark part. (C) Fixed condensing mirror for condensing at least part of the light reflected from the mark part and directing the part of the condensed light to the optical sensor. And (d) a vibration driving means for vibrating the scanning mirror. 8. The optical component according to claim 7, wherein the reflection mirror is smaller than the condenser mirror and is mounted on the condenser mirror. 9. The optical component according to claim 7, wherein the reflection mirror is integral with the condenser mirror. 10. The reflection mirror faces the light source,
8. The front surface covered with a light-reflecting coating, and the condensing mirror has a front surface facing the optical sensor and covered with a light-reflecting coating. Optical components. 11. The vibration drive means comprises a scan motor having an output shaft on which the scan mirror is mounted, the scan motor having alternating circumferential directions at a vibration rate of a plurality of times per second over an arc length of less than 360 degrees. The optical component according to claim 7, wherein the optical component operates so as to reciprocally and reciprocally vibrate the shaft. 12. The light source is a laser light source, and the mark is a bar code symbol.
The described optical components. 13. The optical component according to claim 7, wherein the scanning means includes an electric motor having an output shaft, and the scanning mirror is mounted so as to directly interlock with the output shaft. 14. A lightweight, handy-type laser scanning device for reading a mark and generating an electric signal indicating the mark, comprising: (a) passing a laser beam to the mark and reflecting a laser beam from the mark; A housing having an area for receiving light; (b) a light source in the housing; and (c) a laser for receiving reflected laser light after passing through the housing area and generating a first signal representing a mark. A sensor within the housing, and (d) a plurality of optical elements disposed within the housing that form a generally optical path between the laser light source and the housing area, and between the area and the sensor. The optical elements are (i) a fixed reflection mirror that receives the laser emission from the light source, and (ii) a round-trip arrangement that receives the laser emission from the reflection mirror and sweeps the area across the mark. A movable scanning mirror, and (iii) a fixed condenser mirror arranged to receive the reflected laser light and reflect the laser light to the sensor. A laser scanning device comprising: an optical element of a physically fixed type; and (e) a driving means for reciprocally oscillating the scanning mirror. 15. The laser scanning device according to claim 14, wherein the size of the reflecting mirror is smaller than that of the condenser mirror and is attached to the condenser mirror. 16. The laser scanning device according to claim 14, wherein a signal processing means for processing the first signal into a digital signal is provided in the head. 17. A laser scanning device according to claim 14, further comprising triggering means supported by said housing and operatively connected to a laser light source and a driving means for initiating scanning of the marks. .. 18. The laser scanning device according to claim 14, wherein the driving means includes an electric motor having an output shaft, and the scanning mirror is mounted so as to directly interlock with the output shaft. 19. A lightweight, handheld laser bar code scanner for reading a bar code and generating an electrical signal representative of the bar code, the bar code scanner from a laser source to a reflective mirror, and , First wrapping the laser light passing from this reflecting mirror to the scanning mirror
Forming an optical path, the laser light being reflected in a second optical path having a substantially concave condenser mirror for receiving the reflected light and for passing the light and striking the light sensor,
In the optical scanning device having a driving device for reciprocally oscillating the scanning mirror in the scanner, the method of directing the laser beam to the optical path is as follows: (a) a reflection mirror, a scanning mirror and a condenser mirror Implemented in
The reflecting mirror and the collecting mirror are fixedly and statically fixed to each other, and the step of mounting the scanning mirror so as to oscillate reciprocally by the driving means, (b) the light source, the mirror, and
Arranging an optical sensor in the first and second optical paths. 20. The optical scanning method according to claim 19, wherein the laser light emitted from the laser light source cannot be visually recognized easily by a user.