JPH0612513A - Device and method for optical scanning - Google Patents

Abstract

PURPOSE:To scan a mark in all the directions by electrically energizing a reading starter for imparting vibrational movement to the scanning element of a scanner. CONSTITUTION:On planes orthogonal to each other, a U-shaped spring 204 and a planar spring 222 are arranged so as to be fluctuated. Namely, the arm of the U-shaped spring 204 is vibrated in an X-Z plane and the planar spring 222 is vibrated in an X-Y plane. On the other hand, a scanning element 210 is fitted so as to perform angular oscillating movement alternately circumferentially between first and second scanning terminal positions. Further, although the U-shaped spring 204 is vibrated within a high frequency range for deciding its shape and position, the planar spring 222 is vibrated within a low frequency range. In this case, the amplitude of vibration required for scanning a symbol is decided by the size of the symbol and typically, the optical angle of 10 deg.-30 deg. is formed at least.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning apparatus and method incorporating a scanning element for repeatedly scanning a mark having a portion having different light reflectance such as a bar code symbol at high speed. In particular, the present invention relates to the operation of a scanning mechanism of a type capable of scanning a mark at high speed by a variable and specific omnidirectional scanning pattern.

[0002]

Various optical readers and scanning systems for reading bar code symbols on labels or items have been developed to date. The bar code symbol itself is a coded pattern of marks in which a series of bars of various widths are spaced from each other to form boundaries of spaces of various widths, where the bars and spaces are The reflection characteristics are different. The reader and scanning system electro-optically convert the graphic marks into electrical signals that are decoded into alphanumeric characters intended to represent the item or its characteristics. Such characters are generally represented in digital form and are used as inputs to a data processing system for purposes such as point-of-sale processing and inventory management. A scanning system of this general type is described, for example, in U.S. Pat. No. 4,251,798.
No. 4,369,361, No. 4,387,297, No. 4,409,470, No. 4,760,248, and No. 4,896,026.

As disclosed in some of the above specifications, one example of such a scanning system is in particular a handheld, portable laser scanning head that is gripped by a user. Aim the head at the target to be read and the symbol,
Specifically, the structure is such that a light beam or a laser beam emitted from the head can be aimed.

The light source of a laser scanner is generally a gas laser or a semiconductor laser. The use of semiconductor devices, such as laser diodes, as the light source of the scanning system is particularly desirable due to their small size, low cost, and low power requirements. The laser beam is typically optically modified by a lens to form a beam spot of a given size at the target distance. It is desirable that the size of the beam spot at the target distance is approximately the same as the minimum width between the bars and spaces of the area where the light reflectance is different.

Bar code symbols are formed from bars, generally rectangular-shaped elements that can have multiple widths. The particular arrangement of these elements defines the code used, or the character represented according to the rules and definitions specified in "Symbolology." The relative size of the bars and spaces, as well as the actual size of the bars and spaces, depends on the type of coding used. The number of characters per inch represented by a bar code symbol is called the symbol density. A complete bar code symbol is formed by concatenating the element arrays together to encode the desired sequence of characters, each character of the message being represented by its own corresponding group of elements. Some symbology utilize unique "start" and "stop" characters to indicate the start and end positions of the barcode. There are several different bar code symbologies. These symbologies include UPC / EAN code,
Code 39, code 128, coder bar, and interleaved 2of5 are included.

For the sake of explanation, characters that are recognized and defined by symbology will be referred to as conforming characters, and characters that are not recognized and defined by the symbology will be referred to as non-conforming characters. Therefore, an array of elements that cannot be deciphered by a given symbology represents an incompatible character for that symbology. Recently, several new bar code symbologies have been developed to increase the amount of data that can be represented or stored within a given surface area. One such new symbology, Code 49, introduced the "two-dimensional" concept by vertically stacking character lines instead of horizontally extending bars. That is, not only one row but several rows in the pattern of bars and spaces are formed. See U.S. Pat. No. 4,794,239 for code 49 construction.

The one-dimensional single-line scan normally obtained by a handheld reader is a disadvantage for reading these two-dimensional bar codes. That is, the reading device must be individually aimed at each row. Similarly, multiple scan line readers produce angled scan lines with each other and are not compatible with recognition of Code 49 type two-dimensional bar codes.

In scanning systems known in the art, a light beam is directed by a lens or similar optic along the optical path to a target containing bar code symbols on its surface. The scanning is accomplished by repeatedly scanning the symbols with a light beam that forms a line or series of lines. A scanning element is employed to perform symbol sweeps with a beam spot, trace scan lines passing across the symbol, scan the field of view of the scanner, or both, in fast repeat mode. Drive or scan motor can be incorporated.

Scanning systems typically include a sensor or photodetector that serves to detect the light reflected from the symbol. Thus, the photodetector is located in the scanner, or an optical path in which the scanner's field of view crosses the symbol and extends slightly beyond. Part of the reflected light reflected from the symbol is detected and converted into an electrical signal,
This electrical signal is decoded by electronic circuitry or software into a digital representation of the data represented by the scanned symbol. For example, the analog electrical signal from the photodetector can generally be converted into a modulated digital signal with a pulse width corresponding to the physical width of the bars and spaces. Such a signal is further decoded according to a particular symbology into a binary representation of the data encoded in the symbol and into the alphanumeric character thus represented.

The decoding process of known scanning systems typically operates as follows. The decoder receives the pulse width modulated digital signal from the scanner and an algorithm implemented by software decodes the scan result. During scanning, when the start and stop characters, and the characters between them, are sequentially and completely decoded, the decoding process is complete and the user has an indicator of successful reading (eg, a green lamp and an audible indicator). Beep (or both). If the decoding is unsuccessful, the decoder receives the next scanning result and decodes the scanning result until the scanning result is completely deciphered or no more scanning results are obtained. Continue the process in the form of an attempt.

Such a signal is decoded according to a particular symbology into a binary representation of the data encoded in the symbol and into the alphanumeric character thus represented. In addition to laser scanners, there are other optical devices that can read barcode symbols. For example, another type of barcode reader incorporates a detector based on charge coupled device (CCD) technology. For such readers, the size of the detector is larger than or about the same as the symbol to be read. The entire symbol is illuminated with light from the reader and each CCD cell is read sequentially to determine the presence of bars or spaces. These readers are light weight and easy to use, but in order to be able to read the symbol properly, the reader should be in direct contact with the symbol or the reader should be placed directly on the symbol. There is a need to. Physical contact between the reader and the symbol is the preferred mode of operation for some applications. Or it is a matter of the user's personal preferences.

[0012]

SUMMARY OF THE INVENTION The main object of the invention is to provide different activation levels and / or frequencies,
A control device that electrically biases a reading start device that imparts an oscillating motion to a scanning element of a scanner to generate a specific omnidirectional scanning pattern that controllably fluctuates on a mark read by the scanner. It is to provide an integrated optical scanning device and method.

Another object of the present invention is to provide a controller for energizing the reading initiation device, which forms a precession Lissajous pattern,
It is an object of the present invention to provide a scanning mechanism of the type described above which enables the generation of an omnidirectional scan pattern and results in a pattern of 1/3 of the complete omnidirectional scan described herein. Yet another object of the present invention is to provide a method for generating a novel omnidirectional scan pattern utilizing a scanning mechanism that is characteristically biased.

In summary, it is an object of the present invention that a U of a scanning device is provided which enables the generation of an omnidirectional scanning pattern, preferably with a holder for gripping and engaging the upper edge of the mirror.
Such as an asymmetric scanning element (RASE), which is preferably attached to an oscillating set of members, such as a V-shaped spring,
An object of the present invention is to provide an optical scanning device incorporating a scanning element or a mirror that vibrates at high speed. Although it is not always necessary, by aligning the center of mass of the mirror with the high-speed or high-frequency rotation axis of the scanning element or the mirror in the vibrating member, the vibration property generated in the mounting area of the mirror It is desirable to be able to reduce the stress.

[0015]

To achieve the above object, the optical scanning device of the present invention comprises means for directing an outgoing light beam to the mark and a reflected light beam returning from the mark. In an optical scanning device for reading a mark having a portion having a different light reflectance, the optical scanning device includes: a light emitting unit and a scanning unit for scanning the mark by the light beam; A scanning element, and (b) is arranged to oscillate in two orthogonal planes and cooperates with an angular oscillating motion about respective axes in first and second orthogonal scanning directions High-speed and low-speed vibrations First and second vibrating means arranged to rotate, and angular vibration motion in at least first and second scanning directions between scanning end positions forming a first and second pair. So that you can A holder means for mounting said scanning element; and (c) simultaneously moving said scanning element in said at least first and second scanning directions to perform said scanning between said first and second pair of scanning end positions. Read start means for simultaneously angularly vibrating the elements to direct a light beam along the at least first and second scanning directions; and (d) a read start means connected to the read start means and having different operating energy levels or It is characterized by including a control means for giving a frequency and realizing a variable scanning mode by the scanning element to generate a specific omnidirectional scanning pattern over the entire mark.

Further, in the reading method of the present invention, in the reading method for reading a mark having portions having different light reflectances, a step of directing a light beam from a scanning element of a scanning device to the mark, and the mark The step of collecting the reflected light beam returning from the device, oscillating it in two orthogonal planes, and scanning in cooperation with an angular oscillatory motion about each axis in the first and second orthogonal scanning directions. Mounting the scanning element so as to provide an angular oscillatory motion between the first and second pair of scan end positions in at least first and second scanning directions, the steps including oscillating rotations of the element at high and low speeds. And simultaneously moving the scanning element in at least the first and second scanning directions to simultaneously angle the scanning element between the first and second paired scan end positions. It is dynamic, said at least first and second
Directing a light beam along the scanning direction of the scanning line, and imparting different operating energy levels or frequencies to the reading start means to realize a variable scanning mode by the scanning element to generate a specific omnidirectional scanning pattern over the entire mark. It is characterized by having a step of performing.

[0017]

According to the invention, in particular such as a resonant asymmetric scanning element operating in at least two different frequency modes, which produces a precession Lissajous pattern to enable at least 1/3 omnidirectional scanning of the mark. A novel scanning method and apparatus for omnidirectional scan marks using a single scanning element is provided.

Further in accordance with the present invention, the variable omnidirectional scanning pattern adds control to the electrical energy input to the reading initiation device which operates the scanning elements of the scanning device to terminate the first pair of scanning ends. Obtained by causing an oscillating movement between the position and the second pair of scanning end positions, where the input of electrical energy is in such a way that the scanning element can realize the above-mentioned omnidirectional scanning pattern for the mark. Control and change.

According to a particular feature of the invention, an omnidirectional scanning pattern is realized, in which case a fast Lissajous pattern and a slower Lissajous pattern are combined and controlled by the input of electrical energy to give two Lissajous patterns. An omnidirectional scan pattern is obtained in a manner that does not require the use of an additional motor in the scanning mechanism, as it causes a periodic change in between to form a double Lissajous pattern.

Furthermore, since the relative energy between the different scanning directions of the scanning element changes, for example, in a sinusoidal mode, due to the electric energy input to the reading start means that causes the scanning element of the scanning device to vibrate. It is possible to decipher marks in any orientation, which results in an omnidirectional scanning pattern that allows the representation of the mark in virtually any orientation.

The above variable scan modes for obtaining different types of omnidirectional scan patterns provide both electrical activation frequency and intensity, or both, of the electrical actuation frequency supplied to the read initiation device for the scanning elements used in the scanning mechanism. By controlling one, it is easily implemented using existing scanning devices, especially resonant asymmetric scanning elements. The use of laser scanning devices to scan or read information provided on an object, such as a package or item for sale, is well known in this particular art and is widely accepted commercially. In this regard, various types of laser scanning devices are equipped with an optical reading system, such as a bar code reader, for reading information or bar code symbols on a target subject to scanning by a laser beam emitted from the bar code reader. A scanning head to house is incorporated. Generally, such laser scanning devices, especially bar code reader type laser scanning devices,
Widely used in manufacturing, transportation and retail industries, by permanently incorporating it into the structure of a supermarket checkout counter, the item of merchandise imprinted or pasted with a bar code symbol is Passing over a fixed bar code reader located below, will leave a record to the merchant of the goods purchased by the consumer and give the consumer a reading at the same time (and, if possible, printed It is possible to give a record).

Alternatively, the bar code reader or laser scanning device may consist of an optical scanning device fixedly mounted to a support on which goods can be placed or a stand extending above the countertop. Yes, or in many applications, it may take the form of a small, lightweight, gun-shaped device with a pistol grip, in accordance with a preferred embodiment of the present invention, which device, when activated, is for sale. Alternatively, the target is passed over the imprinted bar code symbol to allow scanning of the information provided by the bar code symbol. According to a particular feature of the invention, scanning is performed by varying the intensity of the electrical energizing current or the frequency of the electrical energizing current, which is composed of an electrically energized magnetic structure and is applied to the reading starter. Vibrations are imparted to the components of the scanning device by a reading initiation device which incorporates a controller for generating various types of omnidirectional scanning patterns for the marks read by the device. Thus, in certain embodiments, the controller for electrically energizing the read initiation device operates the single scanning element in at least two modes to generate a precession Lissajous pattern, Allows ⅓ of an omnidirectional scan with circular overlapping scan lines, which is capable of decoding at least 33.3% of a 360 ° orientation, which allows the scanner to display in either express mode or pass mode. It is possible to deflect marks, such as barcode symbols, at an angle to the scanning direction of the scanner while being scanned.

Another feature of the invention is that the activation of the reading initiation device by the controller causes a scanning element, such as a resonant asymmetric scanning element, to have two available "X" oscillation frequencies of different orders of magnitude. A dual Lissajous omnidirectional scan is provided, and in addition, a transverse mode is provided that oscillates in the "Y" vibration direction, which allows for the last-mentioned motion and high and low speed "X" vibrations. The combination of alternating or periodic switching between them results in two Lissajous patterns that produce an omnidirectional scanning pattern.

The control device of the reading starting device supplies the reading starting device of the scanning element with an electric energizing current whose relative amplitudes of the "X" vibration mode and the "Y" vibration mode continuously change, preferably as a sine wave. The supply enables the decoding of the marks read during this variable start of scanning frequency or amplitude, which allows the generation of an omnidirectional scanning pattern.

[0025]

Embodiments of the present invention will now be described in detail with reference to the drawings. According to an exemplary embodiment, as shown in FIG.
The laser scanning device may be the barcode reading device 100 having a handheld gun-shaped structure, but may have another type of scanner structure.
The bar code reading device 100 includes a pistol grip type handle 153, in which the movable trigger switch 15 is provided.
4 is for activating the laser light by the user and activating the detection circuit when the laser light is directed to the symbol to be read, which allows a long battery life if the device is self-contained. Can be made.
The lightweight plastic housing 155 includes not only a power source or battery 162, but also a laser light source 146, a detector 158, optical elements and signal processing circuits, and a CPU 14.
0 is built in. The output window 156 at the front end of the housing 155 emits the output light beam 151 and enters the reflected input light 152. The reading device 100 aims at the barcode symbol without the user having to position the reading device 100 at a distance from the barcode symbol, ie without touching the symbol or moving across the symbol. Is designed to be Generally, this handheld bar code reader is specified to operate within a distance of perhaps a few inches or more from the point of contact with the symbol.

The reader 100 can also function as a portable computer terminal, and can have a keyboard 148 and a display 149, as described in the aforementioned US Pat. No. 4,409,470.
In addition, as shown in FIG. 1, a matching lens 157 (or multiple lens system) can be utilized to focus the scanning beam on the bar code symbol in the matching reference plane. A light source 146, such as a semiconductor laser diode, is positioned to direct the light beam into the axis of the lens 157, the beam passing through a partially silver plated mirror 147 and any other lens or beam shaping structure required. Then, when the trigger switch 154 is pulled, the vibration mirror or the scanning element 159 attached to the scanning motor 160 that operates is reached. If the light produced by the light source 146 is visible light, it produces a fixed or, if desired, a visible light spot which is scanned just like a laser beam. The user uses this visible light to aim at the symbol with the reader before pulling the trigger switch 154.

As shown in FIG. 2, which illustrates a typical scanning device 200 for implementing a two-dimensional or two-axis scanning pattern, a holder 202 includes a pair of arms 206 and 208.
It incorporates a U-shaped spring 204 having a. Arm 2
A scanning element 210 such as a light reflector or a mirror is fixed to the free end of 08, while a permanent magnet 212 is attached to the free end of the opposite arm 206. The electromagnetic coil 214 is fixed to the upright support member 216, and the lower end portion of the support member 216 is fixed to the base 218. Here, these components 212 and 214 form a reading initiation device for the scanning element 210. An electrical input lead 220 from electrical control device 221 provides an energizing signal to electromagnetic coil 214. The arm 206 and the permanent magnet 212 are provided at one end 222 a of the plane spring member 222.
And the other end 222b is fixed to the base 2.
It is fixed at 18. The flat spring 222 can be manufactured from a compatible flexible material such as a leaf spring, a flexible metal foil, a flat bar. U-shaped spring structure 20
The holder consisting of 4, 206, 208 can be constructed of any metallic material with elastic or flexural properties. Preferred materials include materials such as beryllium-copper alloys. The mass of the mirror 210, which can be equal to the mass of the permanent magnet 212, can in some cases be much larger than the equivalent mass of the U-shaped spring 204. In some situations, it may be desirable to scan the mark with a raster-type or omnidirectional scan pattern, in which case a series of nearly horizontal, substantially parallel scans are provided to evenly cover the desired scan area. The scan line will move laterally from the upper horizontal scan line, and a plurality of intermediate horizontal lines will travel downward to reach the lower horizontal line. In order to obtain a raster type scanning pattern, U-shaped springs 204
And the planar spring 222 can be arranged to oscillate. As shown in the drawings, the arms of the U-shaped spring 204 oscillate in the XZ plane and the plane spring 222 moves in the XY direction.
It vibrates in the plane. With this configuration of the holder structure 202, the mirror or scanning element 210 is configured to perform an angular oscillatory motion between the first and second scan end position pairs in alternating first and second circumferential directions. It is installed. Further, the U-shaped spring 204 is provided for each shape and positioning.
Oscillates in the high frequency range, generally within 200-800 Hz, while the planar spring 222 typically occupies 50-20.
It vibrates within the low frequency range of 0 Hz. The amplitude of the vibration required to scan the symbol depends on the size of the symbol and typically forms an optical angle of at least 10-30 °. Holder structure 202 desirable for certain applications
If the aim is to increase the angular amplitude due to the scan lines caused by, such an increase in angular amplitude is such that the dimensions of the arms are asymmetrical, that is, of different lengths,
It can easily be obtained by constructing a U-shaped spring to form a resonant asymmetric scanning element. Therefore,
In a particular embodiment, the arm 208 comprises at least 2:
At a ratio of 1, it can be shorter than the arm 206. When the U-shaped spring has an asymmetric dimension as described above, the scanning line in the X direction of the raster scanning pattern becomes longer.

In the case of asymmetrically dimensioned U-shaped springs, in addition to being able to increase the angular vibration by 100% compared to symmetrically dimensioned U-shaped springs, the nodes are no longer located in the curved part of the spring. Since it does not exist, durability against metal fatigue and cracks is also obtained. In the case of this type of configuration, the U-shaped spring is held only at the end of the magnet, and the angular vibration of the magnet is several times lower than that of the scanning element, that is, the mirror 210, so that the vibration transmitted to the base 218 is reduced. The advantage is that less is required.

FIG. 3 shows another method for forming an omnidirectional scan pattern, namely, rotating the entire holder means about an axis. The configuration shown in FIG.
The structure is similar to that of FIG. 2, and the same reference numerals indicate the same members, and therefore, the description will not be repeated here for simplification. Any means suitable for rotating the scanning device 200 about its axis can be used to implement an omnidirectional scanning pattern, so that the component 300 for rotating the entire scanning device shown in FIG. , It's just one example. The component 300 includes a motor 302 with a shaft 304 for driving a transmission belt 306. The belt 306 is coupled to a shaft (not shown) connected to the support 308 to rotate the support 308 about a ball bearing 310 attached to the support beam 312. Rotation of the uniaxial scanning device results in an omnidirectional scanning pattern in the form of a rosette.
As the two-axis scanning device rotates, various other omnidirectional patterns result, depending on the type of rotating two-axis device.

FIGS. 4 (A), 4 (B), and FIGS.
2 shows an omnidirectional scanning pattern obtained by the scanning device (scanner) shown in FIGS. For example, in FIG.
And in each of the scanners of FIG. 3, each scanning device is controlled by controller 221 to create a particular omnidirectional scan pattern in a manner that does not require the addition of additional motors or other components to existing scanners of this type. The reading initiation devices 212, 214 of the device are energized with variable current intensity and / or frequency.

The scanning device 200 allows the marks 360 to be displayed.
This is especially true for scanning applications where the scanning device traverses the mark in the case of a specific application intended to perform 1/3 of an omnidirectional scan capable of decoding at least 33.3% of the ° orientation. 6A, which would pass through and then return above, or alternatively, the orientation of the barcode is α =
A mark such as a bar code passes below a fixed scanning point at a specific linear movement speed of, for example, 30 inches / second as long as it is about ± 30 °.
Suitable for the transit mode shown in.

Thus, for example, in the scanning device 200, the precession Lissajous scanning mode is used, and therefore, as is apparent from FIGS. 4 (A) and 4 (B), for example, 60
With 0 scan / sec and 100 frame / sec raster scan, a device for scanning ⅓ in all directions is simply constructed, and ± 30 ° of orientation freedom is obtained with respect to the mark.
In the case of FIG. 4A, the scanning pattern includes two parallel lines, a line of ± 10 °, and a line of ± 20 °. Therefore, for example, as shown in FIG. 5, if the strictest limitation is imposed, a long truncated label of 3/8 inch × 2 inch is assumed, and a barcode having a degree of freedom obtained by dividing its width by its length is assumed. Thus, any symbol has an inherent degree of orientation freedom, for example, utilizing 300 Hz vibration in the "X" direction and 10 in the "Y" direction.
When 0 Hz vibration is used, as shown in FIG.
In essence, generating overlapping omnidirectional scanning patterns, and in representational or transit mode, the symbols, or bar codes, are in an angular scan orientation, with inherent freedom for the scanning device as shown. In between, 3: 1,3., Allowing an accurate and complete scanning of the symbols.
Precession modes such as 1: 1, 3.2: 1 etc. will be available.

Although the star-shaped double Lissajous omnidirectional scan pattern is shown in FIG. 7, the star-shaped double Lissajous pattern is fast for the scanning element at the five calculated points shown in FIG. Switch the "X" vibration frequency to a slower 100-400Hz and vice versa, 15ms
200'Y 'vibrations over a time period such as ec
Obtained by maintaining at Hz. Therefore, RA
In a scanning element such as SE, two available "X" oscillation frequencies are introduced by a controller that biases the reading scanning device.

In summary, the scanning element operates at an oscillating frequency of 100 Hz to 400 Hz in the "X" direction and is maintained at 200 Hz in the "Y" direction.
Therefore, by keeping the "Y" vibration constant and switching between two "X" scan directions or frequencies, one is faster and one is slower.
Two orthogonal 1: 2 Lissajous scan patterns are obtained. This results in the "X" oscillation being essentially switched by the drive signal at the end of each in-phase cycle, as shown by the points represented in FIG. 8 of the drawing, shown in FIG. A star-shaped double Lissajous pattern is formed.

As a result, both "X" and "Y" are
It must be a self-resonant closed feedback loop, and in fact, there are a total of three loops, and each loop provides its own feedback, so these are used to create a precise scanning pattern for a double Lissajous configuration. The exact switching needed to obtain it can be done. On the other hand, if the switching at different points is precisely precise, this again results in a precession pattern which allows an advantageous scanning of the symbols.

It is also possible to use the above-described biasing cycle for the precession pattern, but in this case 1:
If a precise switching of the "X" frequency is not achieved at the switching points in FIGS. 7 and 8, instead of a frequency ratio of 2 or 1: 3, then a precession scan pattern is formed, which is advantageous for the marking by the scanner. It is also possible that it is readable, such as 1: 2.1 or 1: 1.31.

If the strength of the current levels that generate the "X" and "Y" frequencies that cause the scanning element to oscillate, for example, sinusoidally fluctuate, the relative amplitude gradually increases between the "X" and "Y" oscillations. As shown, the activation of the read-initiator in another mode by the controller, as shown, causes a change in the dynamics and enables decoding in any orientation during the possible start-up uptime over 200 ms. It is also possible to obtain a desired omnidirectional scanning pattern as shown in 9 (A) to 9 (D). From the above, in particular, as is apparent from FIGS. 9A to 9D, as a result of the frequency variation between “X” and “Y” due to the variation of the pattern, regardless of the orientation, the barcode A complete scan of such marks is guaranteed.

The urging intensity of the reading starter is changed by the control device, in short, the "X" vibration and "Y" of the scanning element.
Due to the particular omnidirectional scanning pattern obtained by producing a sinusoidal amplitude in both of the oscillations and also when utilizing the rotational movement of the scanning element, as shown in the embodiment of FIG. 10 (A) and 1
As shown in 0 (B), the complete omnidirectional pattern obtained by the integration of the scan amplitude at the start will result. This correlated change in "Y" and "X" oscillations
Decoding of symbols in any orientation is possible with uptime at the beginning of the cycle, which can span time periods up to 200 msec.

From the above, it is possible to simply incorporate the control element 221 into an existing scanner, without the use of additional motors or drive components, in a clear and precise manner,
It is possible to scan the mark in all directions regardless of the orientation offset from the perpendicular. While what has been described as a preferred embodiment of the invention has been illustrated and described, it will be understood that various modifications and changes can be easily made in form or detail without departing from the spirit of the invention. Yes. Therefore, it should be understood that the invention is not limited to the precise forms and details shown and described.

[0040]

As described above, according to the present invention,
Electrically biasing a read-initiating device that imparts an oscillating motion to a scanning element of the scanner at different bias levels and / or frequencies, and controllably varying on a mark read by the scanner; It is possible to realize a scanning configuration of a scanner that incorporates a control device that generates a specific omnidirectional scanning pattern.

[Brief description of drawings]

FIG. 1 is a longitudinal cross-sectional view of a typical handheld gun-shaped laser scanning device incorporating a resonant asymmetric scanning element.

FIG. 2 is a cross-sectional view of an exemplary scanning device of an embodiment of the present invention.

3 is another embodiment of the scanning device of FIG.

4A and 4B are omnidirectional scanning raster patterns obtained by the scanning device of FIG.

FIG. 5 illustrates typical barcode symbol-specific orientation freedom.

6A and 6B show an expression mode and a passing mode for the raster scanning pattern of FIG. 4, respectively.

FIG. 7 shows an omnidirectional scanning pattern obtained by the scanning device of the present invention.

FIG. 8 shows a complete scan pattern for a bias drive signal received from a controller by a read initiation device for a scan element.

9 (A) to 9 (D) show omnidirectional scanning patterns obtained by urging the reading start device, in which the oscillating control device is used to oscillate the amplitude level of the frequency. .

10 (A) and 10 (B) are graphs of vibration amplitudes in the "X" plane and the "Y" plane of the scanning element.

[Explanation of symbols]

 200 Scanning device 202 Holder 204 U-shaped spring 206, 208 Arm 210 Scanning element 212 Permanent magnet 214 Electromagnetic coil 216 Supporting member 218 Base 220 Lead wire 221 Control device 222 Planar spring member 222a, 222b End part of plane spring member 300 Component 302 Motor 304 Shaft 306 Transmission belt 308 Support 310 Ball bearing 312 Support beam

Claims (24)

[Claims] 1. A means for directing an outgoing light beam to the mark, a means for condensing a reflected light beam returning from the mark, and a scanning means for scanning the mark with the light beam. An optical scanning device for reading a mark having portions having different light reflectances, wherein the scanning means is arranged so as to vibrate in (a) a scanning element and (b) two orthogonal planes,
First and second elements arranged to cooperate with angular oscillatory motion about respective axes in first and second orthogonal scan directions to cause high speed and low speed oscillatory rotation of the scan element.
Holder means for attaching the scanning element so as to perform an angular oscillating motion in at least first and second scanning directions between the scanning end positions forming the first and second pairs. (C) The scanning element is simultaneously moved in the at least first and second scanning directions, and the scanning element is simultaneously angularly oscillated between the scanning end positions forming the first and second pairs, and the at least first And (d) a reading start means for guiding a light beam along the second scanning direction, and (d) a variable scanning by the scanning element, which is connected to the reading start means and gives different operating energy levels or frequencies to the reading start means. And a control unit for realizing a specific mode and generating a specific omnidirectional scanning pattern over the entire mark. 2. The optical scanning device according to claim 1, wherein the control means generates a precession Lissajous scanning pattern over the entire mark by the scanning element. 3. The control means biases the reading start means to generate a Lissajous scan pattern and a precession scan pattern with an orientation degree of freedom of about ± 30 degrees for decoding a barcode symbol. The optical scanning device according to claim 2, wherein 4. The optical scanning device according to claim 3, wherein the scanning element performs omnidirectional scanning of the symbol in a representation mode. 5. The optical scanning device of claim 3, wherein the scanning element performs omnidirectional scanning of the symbol in pass mode. 6. The control means for generating a double Lissajous omnidirectional scan pattern over the mark.
The optical scanning device according to claim 1, wherein an input frequency is periodically changed with respect to a pair of scanning end positions in one scanning direction. 7. The control means starts the reading so as to continuously change the amplitude of vibration of the first and second vibrating means in order to generate a Lissajous omnidirectional scanning pattern that changes the orientation with respect to the mark. An optical scanning device according to claim 1, characterized in that the means is energized. 8. The optical scanning device according to claim 1, wherein the control unit changes the intensity or frequency of the current supplied to the reading start unit. 9. The method of claim 1, wherein the first vibrating means is a U-shaped spring having a pair of arms and the scanning element is attached to one free end of the arms. Optical scanning device. 10. The second vibrating means is a flat spring having one end fixed to the end of one arm of the U-shaped spring and the other end fixed to the base. 9. The optical scanning device according to 9. 11. The reading start means has an electric actuator that vibrates the holder means in order to angularly vibrate the scanning element in first and second scanning directions in response to the operation thereof. 11. The optical scanning device according to claim 10, wherein the actuator has an electromagnetic coil having a passage, and a movable magnet attached to a holder means for moving in and out of the passage during operation of the coil. 12. The magnet according to claim 11, wherein the magnet is attached to the holder means in the vicinity of a joining point between the other end of the plane spring and the other arm of the U-shaped spring. Optical scanning device. 13. The first vibrating means vibrates at a high frequency, and the second vibrating means is vibrated at a low frequency, so that at least a frequency within the high frequency is obtained. Overlaying the entire mark in response to a drive signal applied by the control means to the coil of the read initiation means by superposition of the one first signal and the at least one second signal having a frequency in the low range. The optical scanning device according to claim 11, wherein a raster type scanning pattern is generated. 14. The optical scanning device of claim 9, wherein the arms of the U-shaped spring are asymmetrically dimensioned. 15. The optical scanning device according to claim 10, wherein the U-shaped spring is formed of a bent leaf spring. 16. The optical scanning device according to claim 1, wherein the mark is a bar code symbol, and the scanning device is a bar code reading device. 17. A reading method for reading a mark having portions having different light reflectivities, the steps of directing a light beam from a scanning element of a scanning device to the mark, and a reflected light beam returning from the mark. Focusing light, vibrating in two orthogonal planes, and cooperating with angular oscillating motions about their respective axes in the first and second orthogonal scanning directions to rotate the scanning element at high and low speeds. Arranging the scanning element for angular oscillating motion in at least first and second scanning directions between first and second pairs of scanning end positions, and said at least first And simultaneously moving the scanning element in the second scanning direction to simultaneously angularly oscillate the scanning element between the scanning end positions forming the first and second pairs. Directing a light beam along the first and second scanning directions, imparting different operating energy levels or frequencies to the read-initiating means to realize a variable scanning mode by said scanning element to achieve a specific omnidirectional over the entire mark. And a step of generating a scan pattern. 18. The reading initiation means is biased by the scanning element to produce a precession Lissajous scanning pattern across the mark.
7. The reading method described in 7. 19. The reading initiation means is biased to generate a Lissajous scan pattern and a precession scan pattern with an orientational freedom of about ± 30 degrees for decoding barcode symbols. 19. The reading method according to claim 18. 20. The reading method according to claim 19, wherein the reading start means performs omnidirectional scanning of the symbol in an expression mode. 21. The reading start means performs omnidirectional scanning of the symbol in a passing mode.
9. The reading method according to item 9. 22. The reading start means changes the input frequency periodically with respect to a pair of the scanning end positions in one scanning direction in order to generate a double Lissajous omnidirectional scanning pattern over the entire mark. 18. The reading method according to claim 17, wherein the reading is performed as follows. 23. The reading initiation means is biased to continuously vary the amplitude of vibration of the scanning element to produce a Lissajous omnidirectional scanning pattern that changes orientation with respect to the mark. The reading method according to claim 17. 24. The reading method according to claim 17, wherein the reading start means is biased so as to change the intensity or frequency of the current supplied to the reading start means.