JP3152724B2 - Optical system - Google Patents

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 a symbol, such as a bar code symbol, and more particularly to a laser scanning system capable of holding a user and aiming at each symbol to be read. Can,
The invention relates to a lightweight, multi-part portable laser diode scan head. More specifically, the present invention visually searches for each symbol that is read when the head emits or receives light that is not easily visually recognizable to the user and is virtually invisible, and in some cases, A light aiming device for tracking, a trigger for controlling the light aiming device,
An optical assembly of laser diodes, optics that reflect aiming light but transmit light that is not easily visually recognizable, a scanning, focusing and focusing mirror system, and single or multiple components as required Part design, which can be housed in a single handle on the head or in a replaceable handle that is detachable from the head, and light can be transmitted through the selected transparent part of the head The present invention relates to a light-shielding cover for preventing the light-shielding.

[0002]

2. Description of the Related Art Various optical reading devices and optical scanning systems use a bar code symbol provided on an object to identify the object by optically reading the symbol on the object. Is what you read. The bar code symbol itself is a coded pattern consisting of a series of bars of different widths, delimiting different widths separated by spaces, and having different light reflection properties. The optical reader and optical scanning system decode the coded pattern into a multiple alphanumeric representation describing the object. This general type of scanning system is described, for example, in U.S. Pat. Nos. 4,251,798, 4,360,798, 4,369,361,
Nos. 4,387,297, 4,409,470 and 4,
No. 460,120.

As disclosed therein, a particular advantage of such a scanning system is, inter alia, that the laser light is emitted from a hand-held, portable laser scanning head held by the user and the symbol to be read is applied to the symbol to be read. That is, aiming the laser light, repetitively scanning the laser light in a series of scans across the symbol, detecting laser light reflected from the symbol in the scanned laser light, and decoding the detected reflected light. Was in The laser light is usually, but not always, emitted by a helium-neon gas laser that emits red laser light at a wavelength of about 6328 angstroms. Because this red laser light is visible to the user, the user can easily aim the head and position and hold the emitted red laser light on and across the symbol during scanning.

[0004] However, the laser light is, for example, disclosed in US Pat.
Nos. 7,297, 4,409,480 and 4,460,12
In the technology that is emitted by a semiconductor laser diode, as in the specification of specification 0, aiming the head with respect to the symbol is more difficult when the laser light emitted by the laser diode cannot be easily visually recognized by the user. become. In some laser diodes, the laser light is emitted at a wavelength of about 7800 angstroms,
It is very close to infrared and on the border between visible and invisible light. This laser diode light is visible to the user in a dark room, but is invisible in a bright environment where ambient light blocks the laser diode light. Further, when the laser diode light is moved, for example, by being swept across a symbol, especially when the laser diode light is swept multiple times per second, for example, 40 times per second, the laser diode light may be darkened. Even in, 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 the ambient light in the environment in which the laser light is emitted, the scanning speed and other factors, may cause the laser diode to fail. Light is effectively "invisible" or "not easily visually recognizable".

However, since this laser diode light is not easily visually recognizable, a user can easily aim the laser diode light at the symbol without at least considerable difficulty and practical effort. Did not. The user looks for the aim by trial and error and expects the scanning laser diode light to be accidentally correctly positioned on and across the symbol, and the scanning system will typically turn on the indicator lamp, Alternatively, an audible signal (buzzer) sounds and the symbol has been successfully decoded and the user has to wait until the signal is read. This search method is an inefficient and time-consuming symbol reading method, especially in applications where a large number of symbols need to be read every hour and every day.

However, in the context of a laser scanning head that is as light as possible, small, efficient, inexpensive, and desirably made easy to use, the laser diode light cannot be easily recognized visually. Despite their properties, laser diodes have advantages over helium-neon gas lasers. This is because the laser diode is smaller, lighter, consumes less power (voltage supply is 12 V DC or less), has higher synchronization / signal / noise ratio (S / N ratio) than such a gas laser. This is because it can be directly modulated to perform the modulation.

[0007]

However, in spite of the above-mentioned advantages, in addition to its invisibility, due to certain optical properties of the laser diode light itself, the laser diode light can be transmitted to a predetermined outside of the head. At the reference plane, focus to the desired spot size (e.g., a circular spot of 6-12 mils) and also divide this spot size with a predetermined tolerance on both sides of the reference plane at a given depth of focus or depth of field, i.e. within the field of view. Could not be easily decoded and kept within an effective distance that could be read. For example, compared to a helium-neon gas laser, the wavelength of the laser diode light is longer,
The effective distance for the same spot size is shorter. Laser diode light is even more divergent, diverging differently in different planes, and not radially symmetric. Thus, the laser diode light has the same small divergence angle of about 1 milliradian in all planes perpendicular to the longitudinal direction of light propagation, whereas the laser diode light has the p-n of the diode.
It has a large divergence angle of about 200 mrad in the plane parallel to the junction plane, and about 6 m in the plane perpendicular to the pn junction plane.
It has a much larger divergence angle of 00 milliradians. In the single transverse mode (TEMOO), the gas laser light has a radially symmetric, substantially circular cross section, while the laser diode light has a radially asymmetric, substantially elliptical cross section. are doing.

For example, in a so-called geometric way to solve the aforementioned focusing problem and overcome the radially asymmetric nature of laser diode light, it is located at a distance of about 31/2 inches from the head. When the beam spot was focused to have a spot diameter of about 9.5 mils at the reference plane, an optical magnification of over 80 times was obtained. However, at such high magnifications, the use of a single optical focusing element (see, for example, U.S. Pat. No. 4,409,470) requires very precise fabrication, positioning and adjustment. As noted in U.S. Pat.No. 4,387,297, in order to employ highly divergent laser diode light and to distribute the magnification between the elements,
In a lens system designed to have a large numerical aperture, 0.25 aperture, when multiple optical focusing elements are used, the mechanical tolerances of each element are less strict and the positioning And the adjustment procedure becomes easier. However, multiple optical elements occupy more space in the head compared to a single element, increasing weight and cost.

Further, in some cases, during scans across the symbol, ignoring voids in the symbol and dust on the symbol, and further abrupt light-to-dark transitions, the elliptical laser diode light spot may be While this may be more desirable than a circular gas laser beam spot, such an advantage would be obtained if a longer sized elliptical spot was positioned along the height of the symbol. Was. Therefore, in order to obtain such desirable features, the laser diode light had to be correctly positioned in a particular orientation with respect to the symbol. If the symbols are randomly positioned with respect to the laser diode light, the head must be frequently manipulated to direct the laser diode light in the correct direction with respect to the head. This allows
The procedure for reading symbols with laser diode light is no longer efficient, especially in the case of high-volume processing, and the time-consuming situation is further exacerbated. While it is possible to use an anamorphic collimator to make an elliptical laser diode light spot circular, it has further increased the number, space, weight and cost of the optics.

Another problem with both conventional gas laser and laser diode laser scan heads is that they are difficult to adapt to different applications. Different end users have different uses. Some users wish to decode the detected reflected light into data describing the symbols and control the decoding, and some electronic circuits may be located within the head. Some users want to be done. Furthermore, the user's requirements as to whether a rechargeable power supply or data storage device is located in the head or away from the head may be different. Thus, conventional laser scanning systems must be more or less customized for each user, which has been undesirable for both manufacturing and sales. Furthermore, if the user wants to change the standards of the system, the user has had to give up or obtain another system.

Yet another problem with conventional laser scanning heads is that each has a separate light transmissive window. Separate windows are separate components that must be glued in place, and thus, over time, especially if the head is subjected to mechanical shock or abused, the windows may come apart. Was. Once the window is removed, moisture, dust and other contaminants can easily penetrate the interior of the head, thereby covering the internal optics and electronics and disrupting the intended operation.

It is a basic object of the present invention to overcome the aforementioned problems in conventional laser scanning systems.

It is yet another object of the present invention to allow a user to easily aim the head, and more particularly, to direct, or not directly sign, a laser beam emanating from the head that is not easily identifiable visually. Is to be able to condense reflected laser light that is not easily distinguished visually and that is reflected from the camera.

Yet another object of the present invention is to provide a laser light source that emits from a semiconductor laser diode, which is not easily identifiable before and during scanning of a symbol, to allow a user to easily place the laser beam on and across the symbol. Is to be able to aim.

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

Still another object of the present invention is to increase the efficiency of optically reading symbols by using semiconductor laser diode light and to reduce the time.

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

It is another object of the present invention to manufacture a single, high precision, high magnification optical focusing element or to precisely align a diode with a plurality of optical focusing elements. Without having to increase the space occupied in the head by using the element, a semiconductor laser diode light having a substantially elliptical cross section, high divergence, asymmetric in the radial direction, and a long wavelength is used. Focusing on a desired spot size on a predetermined reference plane outside the head, and maintaining the spot size within a predetermined depth of view with a predetermined tolerance on both sides of the reference plane.

Another object of the present invention is to provide a fixed reflecting mirror mounted on or fixed to a fixed concave condensing mirror for transmitting semiconductor laser diode light, and a light-weight substantially flat mirror. An efficient and compact optical reflected light path assembly having a novel optical element including a scanning mirror in the head.

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

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

It is yet another object of the present invention to provide a method for optically reading symbols, particularly black and white symbols used in industrial applications and bar code symbols in a form known as Universal Product Code (UPC). By providing an extremely lightweight, streamlined, compact, handy, fully portable, easy to operate, and fatigue free laser diode scan head and / or system that can be fully retained. is there.

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

[0024]

In order to solve the above problems, an optical system according to one aspect of the present invention includes a laser light source and a laser light sensor that are mounted in a housing and emit laser light for scanning. An optical system for use in an optical scanning device operable to read a symbol having portions having different light reflectivities, wherein a flat reflecting surface for reflecting laser light from the laser light source faces the housing. A fixed plane mirror mounted inside, and reflects while rotating the laser light reflected by the reflection surface,
A scanning mirror rotatably provided in the housing, having a flat reflecting surface for reflecting at least a part of the reflected light from the symbol while scanning the symbol with the laser light, and the scanning mirror A fixed condensing mirror fixed to the housing and having a reflection condensing surface for condensing the reflected light and reflecting the reflected light to the optical sensor; It is smaller than a mirror and is fixed to a fixed light collecting surface of the fixed light collecting mirror. Further, an optical system according to another aspect of the present invention includes a laser light source and a laser light sensor that are mounted in a housing and emits laser light for scanning, and reads a symbol having a portion with a different light reflectance. In an optical system used in an optical scanning device that operates as described above, a fixed plane mirror mounted in a housing such that a flat reflecting surface that reflects laser light from the laser light source faces each other, and the reflecting surface The reflected laser light is reflected while rotating, and the symbol is scanned by the laser light, and the laser light is turned into the housing having a flat reflecting surface for reflecting at least a part of the reflected light from the symbol. A scanning mirror movably provided, and a reflection / condensing surface for condensing light reflected by the scanning mirror and reflecting the light to the optical sensor; Comprising a fixed collector mirror which is fixed in the grayed, the fixed plane mirror is characterized in that it is mounted to a support member within the housing.

The laser beam is reflected from the symbol, and at least a return portion of the reflected laser beam is separated from the symbol and is separated from the symbol by a second
Again travels to the head along the optical path. A scanning motor having an output shaft capable of reciprocating oscillation, for example mounted on a reflective surface such as a scanning mirror, is mounted in the head for scanning the symbols and, during scanning, preferably sweeping several times per second. To repeatedly scan the symbol across the symbol. 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 light reflection characteristics of the bars and spaces forming the symbol are different. .

The head further comprises a sensor, for example one or more photodiodes, which detects the varying light intensity of the return part of the laser light reflected over the entire field of view, and And generating an analog electrical signal indicative of the changed light intensity. The head also has a signal processor that processes the analog electrical signal and typically processes 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.

[0027] If not always, decode / control electronics are provided within the head or at a location remote from the head. The decode / control electronics decodes the digitized signal into the aforementioned data, determines that the symbol has been successfully decoded, and terminates reading of the symbol when the symbol has been successfully decoded. Perform the action. The reading means is provided in the head and is operatively connected to the laser light generating device, the scanning device, the sensor, the signal processing device, and the decoding / control device, and is operated manually to operate 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 trigger device activates the decode / control device, which in turn activates the laser light generator, the scanning device, the sensor, and the signal processing device.

In a typical application, the head held in the user's hand is pointed at each symbol to be read, and once the symbol is located, the user activates the trigger device to begin reading. When the decoding / control device has finished reading the symbol, it automatically alerts the user to that effect, 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 light or the reflected laser light cannot be easily recognized visually is due to factors such as the wavelength of the laser light, the intensity of the laser light, the intensity of the ambient light, the scanning speed, and other factors. It may be caused by one or more of the factors, but in that case a problem arises. Due to this "invisibility", the user cannot see the laser light, cannot know if the laser light is located on the symbol, and if the scanning laser light Can't tell if it is scanning.

Therefore, when such a laser beam that cannot be visually recognized easily is used, the user can visually position the head with respect to each symbol by using the aiming light mechanism according to the present invention, and aiming. Is easier to match. The aiming light mechanism includes an activatable aiming light source, e.g., a visible light emission mounted in the head, operatively connected to the trigger device and, when activated by the trigger device, generates an aiming light that is easily visible to a user. A diode, 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, and illuminates so that at least a portion of each symbol is visible. Aiming device for the user to locate the symbol. The optical path of the aiming light is within one or both of the first optical path and / or the second optical path that is part of the optical path outside the head, and preferably extends parallel to these optical paths. Therefore, it is easy for the user to correctly aim the head at each symbol to be read.

In a preferred embodiment, the aiming light mechanism directs a single illuminating light beam to each symbol to illuminate a substantially circular spot area within the field of view, preferably near the center of the symbol. This single spot area is fixed or stationary during the scanning of the symbol, allowing the user to see both the close-in and far-out symbols both before and during the scan, 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 cannot track a linear scan of the scanning light across the symbol during scanning. In other words, the user cannot know the end position of the laser scan and thus cannot know whether the linear scan extends over the entire length of the symbol or is inclined 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 substantially circular spot areas within and along the field of view. I do. The two spot areas are preferably located at or near the end of the linear scan and remain fixed or stationary during symbol scanning, so that the user can close both before and during the scan. Not only can you see and find both the in and far out symbols, but you can also track the symbols during the scan. However, one of the disadvantages associated with such a stationary pair of light aiming requires two aiming light sources and associated optics, thereby increasing the complexity, weight, size and cost of the system. Is to increase.

In yet another advantageous embodiment, the aiming light mechanism comprises a reciprocating oscillating focusing mirror which operates so that the aiming light sweeps over each symbol and irradiates the symbol with a line area extending along the field of view. Point one aiming light. Such dynamic single-beam 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 that
Because the intensity of the light collected by the human eye is inherently reduced, if the focusing mirror is swept at a high scan rate, such as 40 scans per second, the far-out symbol will be seen and positioned, It is not easy to track.

In yet another advantageous embodiment, the aiming light mechanism directs a single aiming light to a focusing mirror having a stationary state and a reciprocating oscillation state. Initially, the aiming light is reflected from the stationary focusing mirror to each symbol and illuminates 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 caused to reciprocate, reflecting the aiming light to the symbol, which sweeps the symbol and illuminates the symbol with a line area extending along the field of view,
It is designed to track symbols. The reason that such a combination of static and dynamic aiming is highly desirable is that it allows the user to track the close-in symbol during scanning (this is not possible with just a single static light aiming). Moreover, it is not easy because the user can at least find the far-out symbol before scanning (this is not easy with dynamic aiming alone). In most cases, the symbol read is a close-in symbol, so it is not important that the far-out symbol cannot be tracked in embodiments that combine static and dynamic aiming.

In order to achieve such a combination of static and dynamic aiming, the trigger device has a plurality of switching positions and is directly connected to the aiming light source and the oscillating focusing mirror.
Alternatively, it is advantageous to be operatively connected indirectly via a decoding / control device. In the first position, that is, in the off state of the trigger device, all components in the head are put into a start-stop state. In the second position, i.e. the first operating state, the aiming light source is activated and the focusing mirror is placed at a predetermined fixed position, e.g., the center position, for a predetermined time so that the aiming light source illuminates the 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 oscillating the focusing mirror, which starts reading the symbol and illuminating the line area along the field of view.

All of the above embodiments of the aiming light mechanism are manually placed on or at a small distance from the symbol, and then manually dragged and moved across the symbol. This is in stark contrast to the aiming light mechanism provided on the bar-shaped or pen-shaped reader of the present invention. In the latter case,
Since the manipulation of the angle of the pen with respect to the symbol, the speed of the pen, the uniformity of the pen speed and other factors had to be rigorous, it was necessary for a skilled user to perform the above-mentioned exercise. In any case, the manual reader could perform at most one scan per manual operation, and if the symbol was not successfully read on the first attempt, the user had to repeat the manual scan many times.

Another feature of the present invention is a novel optical device for focusing highly divergent, radially asymmetric laser diode light having a substantially elliptical light 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 near 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 a part of the incident laser diode light can pass through the aperture stop while traveling to the symbol. It may have a cross section. The walls that bound the aperture stop block and block the remainder 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 as disclosed in U.S. Pat.No. 4,409,470, in which the incident laser diode light is intentionally allowed to pass through the aperture without obstruction on its way to the symbol. This is in stark contrast to the design. Such an aperture stop of light reduces the numerical value of the aperture from a large value of 0.15 to 0.45 to a value of 0.05, and greatly reduces the optical magnification, thereby achieving the above-described advantage. Only a single focusing lens needs to be used. Although the aperture of such light diminishes the output of the laser diode, the benefits achieved are sufficiently comparable to such a sacrifice that a portion of the incident laser diode light passing through the aperture to read the symbol. Enough output remains.

While the use of aperture stops is well known in optical systems, it is believed that such light aperture stops are novel and not self-evident in laser scanning systems for reading symbols. . As aforementioned,
Although the aperture stop reduces the power of the portion of the incident laser diode light that strikes the symbol, the laser scanning system designer typically reduces the power of the light, especially the portion of the incident light that strikes the symbol and scans it. I don't want to give up my power on purpose. This is because it reduces the power contained in the reflected and focused laser light from the symbol.

Further, the cross-sectional area of the incident laser diode light,
That is, it is well known that when the spot size is a predetermined size, the depth of focus of an optical system having an aperture stop is smaller than the depth of focus of an optical system having no aperture stop. In general, the use of an aperture stop should be avoided, since the designer of the laser scanning system wants to have as large a depth of focus (and thus a correspondingly large effective distance) as possible.

In an optical system having an aperture stop,
It is also known that the minimum laser beam spot size that can be theoretically obtained is larger than that of an optical system having no aperture stop. Thus, in applications where very small spot sizes are required, one would not attempt to use an aperture stop.

In an optical laser system having no aperture stop, the cross section of the laser beam spot has a Gaussian luminance distribution characteristic. In contrast, if an aperture stop is used, light diffraction causes halos or fringes in the beam spot. Such halos and fringes effectively increase the size of the beam spot and produce other adverse effects. The undesirably large size of the beam spot is another reason that aperture stops are not used in laser scanning systems.

From this point of view, using an aperture stop means using complex mathematics according to basic diffraction theory to design an optical system. Because laser scanning system designers often use Gaussian light mathematics, which is simpler than diffraction mathematics, that is another reason why the use of aperture stops in laser scanning systems has not been previously proposed. Conceivable.

The so-called "cold mirror" is used to reflect the visible aiming light to the collecting mirror of the sensor, but the reflected laser diode light reflected from the symbol and collected by the collecting mirror is said cold mirror. , A particularly compact optically reflective optical path assembly is achieved. Yet another useful aspect of the integrated optics assembly is to integrate the collection mirror for the reflected laser light into an integrated multipurpose 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 mirror / collecting mirror combination assembly and a simple, lightweight, reciprocally oscillating scanning mirror. Such an optical assembly provides flexibility in mounting various components in the scan head, and the light weight of the scan mirror improves control of the overall laser light scan pattern. The use of a lightweight scanning mirror further reduces wear on the scanning motor attached to the scanning mirror and extends the life of the motor.

Another highly desirable feature is that the parts of the head are designed to be interchangeable, so that the manufacturer can easily adapt the head to the specific requirements of each user. That is, the different parts can be housed in a single handle for the head, or in a plurality of interchangeable handles for the head, thereby easily adapting the head to the needs of the user and reducing the conventional effort. There is no need to manufacture such custom-made heads.

Yet another advantageous feature is that the head does not need to be fitted with discrete windows, such windows being disengaged from the mounting and the interior of the head being exposed to moisture, dust and other contaminants. Under certain conditions, the possibility of adversely affecting the operation of the head is prevented. To this end, at least a portion of the head comprises an integral light-blocking material structure, and a cover of light-blocking material is provided on the transparent portion of the head to prevent light from passing through that portion, and furthermore, the head has a light-blocking material. The other transparent part 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, cushioning material such as rubber which absorbs impact.

[0048]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an optical system according to the present invention.
Before describing with reference to 5 and 16, a laser scanning head which forms the basis of the present invention and which can be applied to the present invention except for the optical system will first be described with reference to FIGS. .

Referring to FIGS. 1-8, reference numeral 10 denotes a light (less than one pound), narrow body, streamlined, narrow pointed, handy, fully portable, easy to operate,
A generic term for a laser scanning head that does not fatigue the arms and elbows, which head can be fully retained by the user for use in a laser scanning system that reads, scans, and analyzes symbols. The user can aim the scan head at each symbol before and during symbol reading by turning the scan head back. The term "symbol" is intended to encompass marks made up of different parts having different light reflection properties at the wavelength of the light source used, for example a laser. This mark may be, for example, the above-mentioned black and white industrial symbol, for example, code 39, coder bar, interleaved 2 of 5 or the like. Alternatively, it may be an unevenly distributed UPC barcode symbol. The mark may also be alphabetical and / or numeric. The term "symbol" also encompasses marks arranged on a background screen, in which case the mark or at least a part thereof has different light reflection properties than the background screen. In this latter definition,
Symbol "reading" is particularly useful in the field of robots 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 cylinder extending substantially horizontally.
That is, a substantially gun-shaped housing having the body portion 14 is provided. The cross-sectional dimensions and overall size of the handle portion 12 are such that the head 10 is conveniently adapted and retained in the user's hand. The body and handle portion are made of a lightweight, resilient, impact-resistant, free-standing material, such as a synthetic plastic material. The plastic housing is preferably injection molded, but may be vacuum or blow molded and has a volume of about 50
A thin, hollow shell is formed that bounds an interior space that is less than cubic inches, and sometimes less than about 25 cubic inches. Such specific numerical values are not limiting and are a guide for estimating the overall maximum dimension 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 in the direction toward each other, and joins at the nose portion 20 located at the forefront of the head. It has a main part with a wall 18. The body portion 14 also has a rear region having a rear wall 22 spaced apart behind the front walls 16,18. The body portion 14 further includes an upper wall 24, a bottom wall 26 below the upper wall 24, and opposing side walls 2 positioned parallel to each other between the upper wall 24 and the bottom wall 26.
8,30.

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

The handle portion 12 has an upper flange portion 40 having a substantially rectangular cross section extending radially outward. The flange portion 40 also has a forward slot through which the trigger switch 32 projects and moves. are doing. The upper flange portion 40 is elastic and can bend in a radially inward direction. When the upper flange portion 40 is inserted into the neck portion 36, the upper flange portion 40 is supported by the collar portion 38 and bends radially inward until the flange portion 40 exceeds the collar portion 38, at which point the upper flange portion 40 is unique. Due to the resiliency of the spring, it snaps back to its initial non-deflected position and engages the snap locking action behind the collar 38. 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 passes over the collar portion 38, where the handle portion 12 can be pulled out of the neck portion 36. In this manner, the handle portion 12 can be snapped on and off the body portion 14 in a detachable manner, and as will be described later, a separate handle is provided from among the interchangeable handle portions, each containing a different part of the laser scanning system. The part is mounted on the body part so that the head 10 can adapt 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 the trigger switch 32 directly or indirectly by using a control microprocessor as described later. One of the head components is a startable laser light source (see FIG. 4), which is, for example, a semiconductor laser diode 42 operable to propagate and generate incident laser diode light when activated by trigger switch 32. is there. As described above, this laser light is “invisible” to the user or not easily recognizable visually, has high divergence, is asymmetric in the radial direction, has a substantially elliptical cross section, and has a wavelength of About 7000, for example 7800 Angstroms. Advantageously, diode 42 is commercially available from a number of manufacturers, an example of which is Model N from Sharp Corporation.
O. LT020MC. The diode may be a continuous wave type or a pulse type. A low voltage (for example, DC 12 V or less) may be supplied to the diode 42, and a battery (DC) power supply housed in the head or
Alternatively, a replaceable battery pack accessory 44 (see FIG. 7) removably mounted in the head, or a cable 46 (see FIG. 2) connected to the head from an external power source (for example, a DC power source). Power conductors can be used.

The laser diode 42 is mounted on a printed circuit board 48, as shown in FIG. An optical assembly is mounted within the head and is adjustably disposed relative to the diode 42 to optically correct the incident laser light and to provide a nose 20 external to the head along the first optical path. The incident laser light is directed in the direction of a reference plane, which is located before and is substantially perpendicular to the longitudinal direction along which the incident laser light propagates. The symbol to be read is in the vicinity of the reference plane, ie either on the reference plane itself, on one side or on the other side, ie somewhere within the depth of focus or depth of field of the optically modified incident laser light. The depth of focus or depth of field is also referred to as the effective distance over which symbols can be read. The incident laser light is reflected from the symbol in many directions, and the portion of the reflected laser light that travels from the symbol back to the head along the second optical path is called a return portion, which, of course, is visually easily accessible to the user. I can't recognize.

As shown most clearly in FIG.
The optical assembly is provided with an elongated cylindrical optical tube 50, and the cylindrical tube for holding the laser diode 42 in a fixed position by receiving an annular casing portion of the laser diode 42 in one end region of the optical tube 50. 52
And a lens barrel 54 is provided at the other end of the optical tube 50 so as to be able to move vertically. The lens barrel 54 includes an aperture stop 56, a blocking wall 58 surrounding the aperture stop 56 and forming a boundary thereof, and a cylindrical side wall 60 forming a boundary of an internal space.

The optical assembly further includes a converging lens 62, for example, a plano-convex lens, which is arranged in the internal space of the side wall portion 60 in the first optical path and converges the incident laser light on the reference plane. The aperture stop 56 may be disposed on any side of the focusing lens 62, but is preferably on the downstream side. A bias device, that is, an elastic coil spring 64 is disposed in the optical tube 50, and one end of the coil spring 64 is supported on the casing of the laser diode 42, and the other end is supported on the flat side of the focusing lens 62. The coil spring 64 constantly presses the focusing lens 62 against the blocking wall 58, thereby fixing 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 the movement of the lens barrel 54 in the vertical direction. The side wall portion 60 is initially threaded or slidably received against the inner peripheral wall that bounds the optical tube 50, while the side wall portion 60 between the focusing lens 62 and the aperture stop 56
On the other hand, when the desired vertical spacing with the laser diode 42 is adjusted, it is fixed to the inner peripheral wall of the optical tube 50 by, for example, bonding 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 and positioning the focusing lens 62 and the aperture stop 56, and fixes the focusing lens 62 and the aperture stop 56 to the laser diode 42. This is a 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 position of the aperture stop 56, only a part of the incident laser light is located downstream along the first optical path while traveling to the symbol. Can pass through the aperture stop 56. The blocking wall portion 58 blocks the remaining portion of the incident laser light, and prevents 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 which case to transfer more energy to the symbol,
A rectangular or elliptical elongate is aligned with a larger divergence angle of the incident laser light.

According to the law of diffractive optics, the size of the required cross-sectional area of the incident light on the reference plane depends on, among other things, 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 in the same state, the cross-sectional area of 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 the focusing lens 62 instead of upstream, it is not necessary to consider the tolerance of the focusing lens 62 when determining the cross-sectional area of light on the reference plane.

Since the aperture stop 56 is disposed 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 in a plane perpendicular to the emitter and in a plane horizontal to the emitter. Note that since the laser diode light is not radially symmetric, the brightness of the light in the plane perpendicular to the pn junction is strongest at the center of the light and then decreases radially outward. I want to be. The same applies to a plane parallel to the pn junction, but the rate of decrease in luminance is different. Therefore, preferably a small circular opening is oval,
By placing the laser diode light at the center of the larger cross-sectional area, the elliptical cross-section of the light is modified to be approximately circular at the aperture and in both planes perpendicular and horizontal to the pn junction. The light intensity becomes almost constant. The aperture stop 56 preferably reduces the numerical aperture of the optical assembly to less than 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 emitter No. 2 and the aperture stop 56 is about 9.7.
mm to about 9.9 mm. The focal length of the focusing lens 62 ranges from about 9.5 mm to 9.7 mm. When the aperture stop 56 is rectangular, its size is about 1 mm × 2.
mm. The cross section of the light is about 3.0 mm × about 9.3 mm immediately before the light passes through the aperture stop 56. These distances and dimensions are merely exemplary, but allow the optical assembly to modify the laser diode light to 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 20. It is possible to focus light to have. The effective distance may be such that the aforementioned close-in symbol can be placed anywhere from about 1 inch away from the nose 20 to the reference plane, and the aforementioned far-out symbol can be placed about 20 inches away from the reference plane. It can be placed at any position from to the reference plane.

The portion of the incident laser light passing through the aperture stop 56 is converted by the optical assembly into an optical axis 102 in the head 10.
Back along along to a substantially flat scanning mirror 66 from which it is reflected. The scanning mirror 66 forwards the laser beam impinging thereon along the optical axis 104 to the upper front wall 6.
8, a forward-looking, laser-transmissive window 68 mounted on
Through to the sign. As clearly shown in FIG. 9, a representative symbol 100 is shown near the reference plane, and if it is a barcode symbol, from a series of vertical bars spaced apart from each other along the length. Made up 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 activated by the trigger switch 32, makes an oscillating motion that reciprocates reciprocally in the lateral direction.
This is because in a linear scan, the incident laser light is swept across all the bars of the symbol in the longitudinal direction. Laser spots 106a and 106b in FIG. 9 indicate the instantaneous end positions of the linear scanning. The linear scan can be performed at any position along the bar height, 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 a preferred example, the area of the linear scan is 5 inches long at the reference plane.

The scanning mirror 66 is mounted on a scanning device,
This is preferably a high speed scanning motor 70 of the type shown and described in U.S. Pat. No. 4,387,397, the contents of which are incorporated in and incorporated herein by reference. For the purpose of this application, the scanning motor 70 is mounted on the output shaft 7 to which the support bracket 74 is fixedly attached.
It would suffice to point out that we have 2. The scanning mirror 66 is fixedly mounted on a support bracket 74. The high-speed scanning motor 70 causes the output shaft 72 to vibrate alternately, reciprocally, and repetitively in the circumferential direction at a desired arbitrary size of arc length, typically 360 degrees, at a plurality of vibration speeds per second. Driven as follows. In a preferred embodiment, scanning mirror 66 and output shaft 72 oscillate in conjunction,
The scanning mirror 66 is at approximately 32 degrees angular spacing at the reference plane, i.e., over the arc length, and at 20 scans per second or 40 scans per second.
At the speed of oscillation, the incident laser diode light impinging on the scanning mirror 66 is swept repeatedly.

Referring again to FIG. 2, the light intensity at the return portion of the reflected laser light is variable on the symbol during scanning because the various portions that make up symbol 100 have different light reflection characteristics. The return portion of the reflected laser light is collected by a substantially concave, spherical collection mirror 76 and by upper and lower boundaries 108, 110 as shown in FIG. 2 and as shown in FIG. Opposite borders 112, 114
A conical light stream within a conical light collection volume bounded by The condensing mirror 76 reflects the conical light condensed along the second optical path, via the laser beam transmitting element 78 to a sensor, for example, a photosensor 80, along the optical axis into the head. Condensed conical laser light directed to photosensor 80 is coupled to upper and lower boundaries 118,120.
(See FIG. 2), and opposite boundaries 122, 124
(See FIG. 3) defines the boundary. A photosensor 80, preferably a photodiode, detects the variable brightness of the focused laser light over a field of view extending along a linear scan area, preferably beyond that area, and detects the detected variable light intensity. To generate an analog electrical signal indicating

Referring again to FIG. 9, reference numeral 126 indicates an instantaneous focusing zone for symbol 100 from which the instantaneous laser spot 106 reflects. In other words, the photo sensor 80 looks at the focusing zone 126 when the laser spot 106 hits the 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 repetitively oscillates laterally,
The longitudinal field of view of the photodiode is swept across the symbol in the linear scan area. Light collection zones 126a, 126
b indicates the instantaneous end position of the linear scan of the visual field.

The scanning mirror 66 and the condensing mirror 76 have a monolithic structure in a preferred embodiment. As shown in FIG. It was done. Plano-convex lens 8
2 has a first substantially flat outer surface at the portion coated with the first light reflecting layer, which forms a flat scanning mirror 66, and at the portion coated with the second light reflecting layer. It has two substantially spherical second 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,
It may be a discrete, small flat mirror that is glued or molded at a suitable position and angle to a silver-plated concave mirror at a predetermined position.
As will be described below, the concave focusing mirror 76 not only serves to focus the return portion of the laser light and focus it on the photodiode 80, but also directs the aiming light outside the head and focuses it there. Performs 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, a signal processing device having components 81, 82, and 83 on a substrate 84 is a sensor 8
It operates to process the analog electrical signals generated by the zeros and produce digitized video signals.
The data describing the symbols can be derived from the video signal. A suitable signal processor for this purpose is described in U.S. Pat. No. 4,251,798. Components 87 and 89 on substrate 86 constitute a drive circuit for 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 an 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 U.S. Pat. Nos. 251,798 and 4,387,297.

The digitized video signal is connected by an electrical connection comprising a socket 88 provided on the body section 14 and a compatible plug 90 provided on the handle section 12. The plug 90 is automatically and mechanically connected to the socket 88 when the handle portion 12 is attached to the body portion 14.
Compatible with. The handle portion 12 further includes a pair of circuit boards 9.
2, 94 (see FIG. 1) are mounted, and various components are mounted thereon. For example, a decoding / control device consisting of parts 95 and 97 serves to decode a digitized video signal into a digitized decoded signal, and from this decoded signal a desired data describing a symbol according to a software control program. Is obtained.
The decoding / control device stores the control program in PRO.
M, a RAM for temporarily storing data, and a control microprocessor for controlling the PROM and the RAM. The decoding / control unit determines that the decoding of the symbol is successfully achieved, and terminates the reading of the symbol when the symbol is successfully decoded. The reading is started by pressing the trigger switch 32. Decoding /
The controller further controls the start-up components in the head that are triggered by the trigger switch 32, and also automatically terminates reading to the user, for example, by sending a control signal to the pilot lamp 96 to turn on the lamp. It also has a control circuit for notifying that.

In one embodiment, the decoded signal is transmitted to a remote host computer 258 via signal conductors in cable 46, where the host computer 25
8 basically functions as a large-scale 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 part 95, is mounted on handle 12 and
The read plurality of decoded signals are stored. The stored decoded signal can be unloaded to a remote host computer. By having a local data storage device, the need to use the cable 46 during symbol reading is eliminated, which is highly desirable for operating 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 that can be exchangeably mounted on the body portion 14. In one embodiment, the handle portion 12 is left empty, in which case the video signal is transmitted to a remote decode /
The data is transmitted via the cable 46 to be decoded by the control device. In another embodiment, only the decode / control device may be implemented on handle portion 12, in which case the decoded signal is transmitted over cable 46 for storage at a remote host computer. In yet another embodiment, the decode / control device and the local data storage device can be housed in the handle portion 12, in which case the stored signals decoded by the multiple readings are transmitted to a remote host computer. It can be unloaded and the cable 46 is connected only to unload the stored signal.

Alternatively, rather than having a set of detachable handles, a single handle can be fixed to the head in a non-detachable manner, in which case the detachable handle end 128 is removed and replaced. This allows different components to be mounted on removable circuit boards 92, 94 optionally provided in a single handle.

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

Further, in accordance with the present invention, an aiming light mechanism is mounted within the head, and may alternately be used in such situations where the laser light incident on the symbol and reflected from the symbol is not readily visually recognizable to the user. It is intended 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 a startable 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 decode / control device, the aiming light source 130 propagates and generates diverging aiming light. Since this light is visible to the user and its wavelength is about 6600 Angstroms, the color of the aiming light is almost red, compared to the white light around the environment where the symbol is located.

The aiming mechanism is further mounted in the head 10 to direct aiming light from the aiming light source along the aiming light path to the reference plane and each symbol, and to illuminate at least a portion of each symbol visually. 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.
It is mounted on a slanted support 132 for directing toward. On the way to the optical element 78, the conical aiming light travels to the upper and lower boundaries 134, 136 (see FIG. 2) and the opposite boundaries 138, 140 (see FIG. 3).
Are bounded by As described above, the laser light focused by the optical element 78 is
, And filters out ambient light noise from reaching photosensor 80.
Optical element 78 also reflects aiming light that strikes 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 transmits light in the wavelength range of the laser light. The aiming light is reflected from the cold mirror 78 along an optical axis substantially collinear with the optical axis 116 of the laser light condensed between the condensing mirror (concave mirror) 76 and the photosensor 80, and collides with the concave mirror 76. I do. The concave mirror 76 collects the aiming light, and the concave mirror 76
A function of reflecting the aiming light along an optical axis substantially collinear with the same optical axis of the laser light condensed between the symbol 100 and the symbol 100. Concave mirror 76 acting as a focusing mirror for aiming light
Is approximately 8 inches to 10 inches from the nose portion 20 of the head 10.
At inches apart, the aiming light is focused to a circular spot size of about 1/2 inch. Since the optical path portion of the aiming light located outside the head 10 coincides with the optical path portion of the condensed laser light located outside the head, the portion of the symbol illuminated by the aiming light, that is, the symbol that is made visible, It can be said that the photo sensor 80 sees the reflected laser light that cannot be easily recognized visually.
In another variation, a cold mirror is located in the first optical path,
Aiming light is directed to the cold mirror, and the optical axis of the aiming light is aligned with the optical axis of the output incident laser light, thereby directing the aiming light to the symbol so as to coincide with the output incident laser light. You may do so.

As shown in FIG. 10, the aiming LED 13
In the first static single light aiming embodiment, 0 is positioned relative to a fixed optical element (eg, a focusing lens) 142 fixedly positioned in the aiming light path in the head. be able to. The focusing lens 142 serves to focus the aiming light to the respective symbol 100 and direct the light there to illuminate the 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 prior to scanning and during the scanning of the symbol reading.
With the static single light aiming embodiment shown in FIG. 10, both the close-in and far-out symbols can be searched and viewed, and the far-out symbols are far from the head. As such, it is only illuminated at a lower brightness, but still visible to the user. However, as described above, the fixed spot area 1
50 does not provide much help in tracking the scan across the symbol.

Next, as shown in FIG. 12, in the second static pair of light aiming embodiments, a focusing lens in which a pair of aiming LEDs 130a and 130b identical to the aiming LED 130 is fixed. The focusing lens 142 is disposed at an angle with respect to the
b to direct the aiming light to the same respective symbol, and illuminate so that a pair of spot areas 152, 154 located in the field of view on these symbols and linearly spaced from each other along the field of view. Perform the function of Spot area 15
2,154 and a circle near the end of the scan area, illuminated before and during scanning of each symbol so that the symbol can be searched and tracked both before and during symbol reading. Is preferred. With the static paired light aiming embodiment shown in FIG.
Both fur-out symbols can be searched and viewed, and the far-out symbols are illuminated at lower brightness because of their greater distance from the head, but are still visible to the user. As mentioned above, a pair of fixed spots 152, 154 is a useful aid in tracking a scan across a 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 with respect to the scanning / focusing / focusing components to sweep the aiming light across each symbol, and a line area 156 (FIG. 13) extending over the symbol along the field of view.
Irradiation). Line area 156 is illuminated during scanning to track the symbols during reading of each symbol. The close-in symbol is well illuminated even when scanning is performed at a speed of 40 scans or more per second. However, in the case of the far-out symbol, the distance from the head is large,
The line area 156 is less visible because the scanning speed is faster.

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

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

Thereafter, 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, and the second operation state is established. In the second operating state, the trigger switch 32 switches all of the remaining activatable components in the head 10 to, for example, the laser diode 42 and the focusing mirror 7.
6. Scan motor 70 for vibrating 6, photodiode 8
0, activate the signal processing circuit and other circuits in the head to start reading symbols. Since the collecting mirror 76 is not fixed but oscillated, the aiming light is dynamically swept across the symbol and is identical to the line area 156 in FIG.
Illuminate so that line areas extending along the field of view are visible. Thus, it helps the user to track the symbol while reading the symbol during scanning. With such symbol tracking, a close-in symbol is very clearly visible, while a far-out symbol is less so.

The aforementioned continuous activation of the components in 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 components thereon are supported on the blocking member, and a rear impact blocking member 174 is also provided. The scanning motor 70 and the sighting lamp 130 are supported on the blocking member. Supported 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 scanning head that scans the output incident laser light and the field of view of the sensor. The present embodiment is not limited to this, and it goes without saying that other modified examples can be applied. For example, while the field of view is not scanned, the outgoing incident laser light is directed at the symbol through one window in the head, swept across the symbol, and the returning laser light is focused through another window in the head. Other forms are possible, such as directing the output incident light to 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, use environment, size, selection and arrangement of electronic and mechanical parts, necessary cushioning inside and outside the housing, and the like.

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

The laser scan head of the present invention provides high, medium and low density within the approximate effective range of 1 inch to 6 inches, 1 inch to 12 inches and 1 inch to 20 inches, respectively. It is possible to read each bar code symbol. The high density, medium density and low density bar code symbols described herein have a minimum width of 7.5 mil, 15-20 mil and 30 mil, respectively.
A symbol with bars and spaces that are ４０40 mils. In a preferred embodiment, for symbols of known density, the position of the reference plane can be optimized for the maximum effective distance of the symbol. Other means may be provided in addition to the aiming light mechanism of the previously described embodiment to assist the user in aiming the head at the symbol. For example, a configuration is possible in which a user looks into a protruding viewing device formed on an upper portion of the housing and extending along the first or second optical path. An observation port having a viewing window may be provided on the head so that a user can search for a symbol in the window by looking through the viewing window. Acoustic ranging devices can also be used to find symbols. The ranging device emits an acoustic signal, detects an echo signal, and activates an acoustic indicator in response to the detection. The audible indicator signals the user that a symbol has been found by emitting a sound or changing the speed of a series of sounds or acoustic signals.

In another aspect of the present invention, the aiming light spot on the above-mentioned symbol is used, for example, to make it easier to see the spot.
Or, it may be desirable to flash to save 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 laser scanning head of the same type as that of FIG. For simplicity, the same parts in FIG. 14 have the same reference numerals as the corresponding parts in FIG.

The difference between FIG. 2 and FIG.
One important difference of the head 10 'is that the body 1
4 'comprises two housing parts, an upper housing 180 and a lower housing 182, which are preferably snap-fitted and assembled to one another. 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-transmitting transparent synthetic plastic. Since both output and input light can pass through the transparent upper housing 180, the window area 186
A cover 184 made of a light shielding material covers the entire outer surface of the transparent upper housing 180 except for the display area 188 and the display area 188. The cover 184 is made of an injection-molded thermoset rubber-like material, the inner surface of which closely fits the outer surface of the upper housing 180, is in close contact with the entire outer surface of the upper housing, and has a friction-type outer surface. Is held in. The cover that fits perfectly is actually the window area 186 and the display area 18.
All portions of the transparent upper housing 188, except for 8, are shielded to prevent output and input light from passing therethrough.

As described above, it is not necessary to separately bond or mount a discrete window at a predetermined position of the head unlike the conventional head. Window area 186 not covered
Functions as a window for both output and input light. The uncovered window area 186 as well as the upper housing 180
The window is disengaged from the mounting, and is covered by dust, moisture and other contaminants as in the conventional case, preventing proper operation of the optical and electrical components in the head. The danger is gone.

Further, since the display area 188 is not covered with the cover 184, light from the display lamp 96 'can shine through the above-mentioned area. In addition, since it is not necessary to attach a separate window in the area of the indicator lamp 96 'as in the conventional type, it also helps to seal the head inside very effectively.

The rubber-like cover is thick and has a cushioning effect,
Preferably, it is resilient and serves as a buffer for the head. 14, it can be seen from FIG.
It can be seen that the joint between 0,182 has a lower curved flange, which is a very effective gasket-like sealing means.

A further difference between the embodiment of FIGS. 2 and 14 is that a sealing partition 190 is provided at the trigger switch 32 '. The sealing septum 190 has an actuator 192 in the 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 194 of the trigger switch 32 '. In operation, when the trigger switch 32 ′ is manually pressed, the display lamp unit 194 forcibly pushes the actuator 192 to the button 16.
4 'to activate switch 160'. During this operation, the diaphragm 190 shields the interior of the head from the outside in the area of the trigger switch, thereby providing another entry point for contaminants such as dust and moisture that would have been free to enter in the conventional case. Is closed.

A further 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 an 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. At the front end of the gantry,
Projecting portion 206 passes through a groove 208 formed in a conduit provided in the lower portion 204 and snap-fits behind the groove. At the back of the gantry 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 of the housing and the front of the gantry 200, and the back cushioning member 174 ′ is mounted on the gantry 200.
And the inwardly extending partitions 175, 177 provided on the back of the head.

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

Another difference is that the handle fitting portion 12 is provided.
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 aforementioned members, and combinations of two or more thereof, can be usefully applied to a different type of application than the aforementioned structure.

FIG. 15 shows an embodiment of the optical system of the present invention. This optical system is shown in FIGS.
Or a scan head of the type shown in FIG.

The optical system shown in FIG.
It has. The laser light source 216 comprises a helium-neon laser tube or laser diode that emits light that is not readily visible or visually recognizable as described above. The laser light source 216 can further include an aiming optical element that forms a laser beam as described above.

The optical system shown in FIG.
18 are provided. As shown in FIG.
18 can be fixed to the concave condensing mirror 220.
Alternatively, the reflecting mirror 218 may be mounted on a support member in the scanning head as long as the reflecting mirror 218 is fixed in a stationary relationship with the concave focusing mirror 220. In any case, the reflection mirror 218
Converts the incident laser light into a scanning mirror 232 as described below.
It is mounted at an appropriate angle so that it faces toward.

The concave focusing mirror 220 is a support bracket 2
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 transmitted from the laser light source 216 to the mark 2 along the first optical path.
Proceed to 26. This first optical path is shown by a solid line with an arrow in FIG. The incident laser light reflects off of the mark 226, where the laser light is directed along a second optical path 230 indicated by the set of dotted lines in FIG.
Go back to 8.

The light-weight movable scanning mirror 232 receives the incident laser light on the first optical path and reflects this laser light to the mark 226. The scanning mirror 232 further receives the reflected laser light reflected from the mark 226 along the second optical path, and reflects this reflected laser light to the concave condensing mirror 220. The concave condensing mirror 220 is preferably a spherical concave mirror. The concave condensing 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 a shaft 234 of a scanning motor (not shown). Scanning mirror 232
It is preferable that reciprocating vibration is performed a plurality of times per second, typically 40 scans per second, about the axis 238 as indicated by an arrow 236. Such reciprocating vibration of the scanning mirror 232 allows the laser light to scan the mark 226 bidirectionally. The axis 234 may simply rotate the scanning mirror 232 so that the laser beam scans over 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 a first optical path 224. This light strikes a reflecting mirror 218, which reflects the light to a 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 luminance has changed to the scanning mirror 232 again. Scanning mirror 230 reflects the light to concave collecting mirror 220, which reflects the light to photodetector 228. Photodetector 228 detects the changing brightness of the light and generates 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 signal cord. Thus, the battery pack (not shown)
Supplies power to all of the various components in the scan head.
The scan head also generates a radio frequency (RF) signal that is transmitted to a host computer for further processing. The scan head may further include a receiver for receiving transmissions from a host computer to control various mechanisms of the scan head.

In the above-described embodiment, the case where the present invention is applied to a portable laser diode scanning head has been described. However, the present invention is not limited to this. Needless to say.

[0108]

As described above, since the optical assembly is provided with the fixed-type reflecting mirror / condensing mirror combination assembly and the simple structure and the lightweight scanning mirror, the entire scanning pattern of the laser beam can be controlled. The performance is improved. In addition, current consumption of the scanning motor attached to the scanning mirror is reduced, battery consumption is prevented, and wear of the scanning motor is reduced, thereby extending the life.

[Brief description of the drawings]

FIG. 1 is a front view showing, as a reference example, a scanning head to which the optical system of the present invention can be applied.

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

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. 2;

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

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

FIG. 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 integrated scanning / focusing / focusing mirror component along line 8-8 of FIG. 1;

FIG. 9 is an enlarged view of a symbol and a part of the symbol that a laser beam impinges on and reflects from.

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

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

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

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

FIG. 14 is a diagram showing a scanning head to which the optical system of the present invention can be applied.

FIG. 15 is a diagram schematically illustrating an optical system according to an embodiment of the present invention.

FIG. 16 is a schematic view of a laser scanning head showing the arrangement of the optical assembly of FIG. 15;

[Explanation of symbols]

 DESCRIPTION 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 Electrical switch 62 Focusing lens 64 Coil spring 66 Scanning mirror 74 Support bracket 76 Condensing mirror 80 Photosensor 100 Symbol 130 Aiming light source 216 Laser light source 218 Reflecting mirror 220 Concave condensing mirror 224 First optical path 226 Mark 228 Photodetector 230 Second optical path 232 Scanning mirror 234 Axis 258 Host computer

──────────────────────────────────────────────────続 き Continued on the front page (72) Boris Metricy, Inventor, New York, USA 11790 Stony Brook Milstream Lane 18 (72) Inventor, Edward Burcan, United States, New York 11720 South Cittoke Lynn Street 8 Examiner Shun Umezawa (56) References JP-A-3-182979 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G06K 7/10

Claims (3)

(57) [Claims] A laser light source and a laser light sensor that are mounted in a housing and emit laser light for scanning;
An optical system for use in an optical scanning device that operates to read symbols having portions having different light reflectivities, wherein the flat surface reflecting a laser beam from the laser light source is mounted in a housing so as to face each other. A flat mirror that reflects the laser light reflected by the reflecting surface while rotating, scans the symbol with the laser light, and reflects at least a part of the reflected light from the symbol. A scanning mirror rotatably provided in the housing, having a reflective surface, and a reflecting light collecting surface for condensing light reflected by the scanning mirror and reflecting the light to the optical sensor; A fixed converging mirror fixed in the housing, wherein the fixed flat mirror is smaller than the fixed converging mirror, An optical system characterized by being fixed. 2. A laser light source and a laser light sensor which are mounted in a housing and emit a laser beam for scanning.
In an optical system used in an optical scanning device that operates to read a symbol having a portion having a different light reflectance, a flat reflection surface that reflects laser light from the laser light source is mounted in a housing so as to face each other. And a flat mirror that reflects the laser light reflected by the reflecting surface while rotating, scans the symbol with the laser light, and reflects at least a part of the reflected light from the symbol. A scanning mirror rotatably provided in the housing, having a reflective surface, and a reflecting light collecting surface for condensing light reflected by the scanning mirror and reflecting the light to the optical sensor; An optical system comprising: a fixed condenser mirror fixed in a housing; wherein the fixed plane mirror is mounted on a support member in the housing. M 3. The optical system according to claim 2, wherein said scanning mirror is provided in said housing so as to be capable of reciprocating vibration or rotatable in one direction.