Optical reader having inclinable stage which mounts optical unit thereon

An optical reader which is compatible with every environment irrespective of installation and usage environments, thereby enabling uniform manufacturing, satisfactory reading reliance, and operative safety and user-friendliness. The optical unit is mounted on the stage, and there is provided an inclination apparatus which inclines the stage at a desired angle. Thereby, without changing a preset optimal scanning pattern, only its emitting direction becomes changeable freely.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to optical readers, and more particularly to an optical reader that changes a light scanning direction. The optical reader of the present invention is especially suitable for barcode scanners which optically read a barcode put on merchandises in POS systems and the like.

2. Description of the Related Art

Recently, barcode scanners have become more frequently used for cashiers in supermarkets, discount stores, home centers, etc. In general, operators who use a barcode scanner fixed onto a cashier table move a merchandise on which a barcode is printed, whereby the merchandise may pass across a scanning pattern emitted in a predetermined direction from a read window of the barcode scanner.

The scanning pattern is usually fixed to one pattern, and its emitting direction is preset and fixed in accordance with the installation and usage environments of the scanner at the time of manufacturing. The “installation environment”, as used herein, means a direction in which the read window is to be installed in a cashier table; more concretely, whether the read window is arranged parallel or perpendicular to the cashier table. The former barcode scanner is called a lateral type, and the latter a longitudinal type. The “usage environment”, as used herein, means a moving path of a merchandise onto which a barcode is printed; for example, whether the merchandise is to be moved from right to left or left to right, even in the same lateral type. The usage environment depends upon each operator's height, experience and the like.

The emitting direction is usually preset and inclined by a predetermined angle relative to a direction perpendicular to the read window, toward an upper stage from which a merchandise comes (for instance, which is a right side if the merchandise moves from right to left).

With the spread of barcode scanners, prompt reading of barcodes and efficient manufacturing of the barcode scanners has been strongly demanded.

However, the conventional longitudinal and lateral barcode scanners are different in manipulation and optimal scanning-pattern emitting directions. Even in the same lateral type, a proper emitting direction is different between one which moves merchandise from right to left, and another which moves merchandise from left to right. Therefore, in an attempt to install and use the conventional barcode scanners each store has ordered apparatuses having a different pattern emitting directions which correspond to their installation and usage environments.

A change of the emitting direction requires a change of inclination of an optical system that generates a scanning pattern and/or an arrangement of optical element(s). Consequently, each barcode scanner, even for the same type, should be manufactured differently in emitting direction for every business type of different installation and usage environments, causing inefficient manufacturing and price increasing. On the other hand, primarily for manufacturing purposes, there have been proposed apparatuses having a fixed emitting direction while the installation and usage environments are ignored, but these apparatuses cannot generate an optimal pattern to achieve an object of prompt reading.

On the other hand, the actual prompt reading depends, in addition to the scanning pattern, upon a moving path of merchandise (or barcode) by an operator. Even in a barcode scanner in which the scanning pattern is fixed to the optimal pattern for the installation and usage environments, a moving path slightly different among operators depending upon their heights, experiences, skillful hands, habits, etc. Disadvantageous, each operator must adjust a barcode moving path and spend along time to master the operating skill.

To eliminate these problems, applicant has proposed, in Japanese Laid-Open Patent Application No. 9-16705, a barcode reader that generates a plurality of scanning patterns by making mirrors movable in the optical system, extending a scan area, and selecting one frequently used scanning pattern from them. Nevertheless, this invention was disadvantageous because it has a low reading reliance and does not always meet operative safety requirements.

The scanning pattern frequently used in this reference is not the actual optimal scanning as a result of simulation taking into account the arrangement between a laser source and a light receiving element, while minimizing optical noises caused by mirror angles and the light amount of the laser beam. A scanning pattern including optical noises, even though hitting a barcode, cannot properly read the barcode data. For instance, a certain mirror angle puts the reflected light over the store's light as a noise, and the light receiving element receives a large amount of incident light. A laser beam reflected at an edge or the like of the reflection mirror also causes a large amount of light incident to the light receiving element. In this way, a plurality of scanning patterns which have been generated only by taking into account the usage environment without paying attention to the optical noises would lower the reading reliance and delay the reading time. It is preferable to maintain the optimal scanning pattern that is set at the time of manufacturing.

In addition, as seen in the International Standard IEC and the U.S. Standard CDRH, which take care of human eyes subject to a laser beam, the laser safety standards define certain restrictions regarding the light amount of an incident laser beam. However, the light amount of an arbitrarily changed scanning pattern would not necessarily meet the above standards, thereby endangering safety.

BRIEF SUMMARY OF THE INVENTION

Accordingly, it is a general object of the present invention to provide a novel and useful optical reader in which the above disadvantages are eliminated.

More specifically, it is another object to provide an optical reader which enables uniform manufacturing irrespective of the installation and usage environments.

It is still another object of the present invention to provide an optical reader that is user-friendlier than the conventional ones.

It is another object of the present invention to provide an optical reader which maintains the optimal scanning pattern and has a high reading reliance.

It is still another object of the present invention to provide an optical reader that meets the laser safety standards and secures safety.

In order to achieve the above objects, an optical device of the present invention comprises an optical unit which generates a predetermined scanning pattern, emits the predetermined scanning pattern to an optically readable medium, and receives light reflected from the medium, a stage which mounts an optical system at least necessary to generate the predetermined scanning pattern from among the optical unit, and an inclination apparatus which inclines the stage.

Another optical device of the present invention comprises an optical device which includes a housing having a plurality of reading windows, a plurality of optical units accommodated in said housing, the number of the optical units corresponding to the number of reading windows, each optical unit generating a predetermined scanning pattern, emitting the predetermined scanning pattern to an optically readable medium, and receiving light reflected from the medium, a stage, accommodated in the housing, which mounts an optical system at least necessary to generate the predetermined scanning pattern from among the optical unit, and an inclination apparatus, accommodated in the housing, which inclines the stage.

Still another optical device of the present invention comprises an optical unit which generates a predetermined scanning pattern, emits the predetermined scanning pattern to an optically readable medium, and receives light reflected from the medium, a stage which mounts an optical system at least necessary to generate the predetermined scanning pattern from among the optical unit, an inclination apparatus which inclines the stage, and a controller connected to the inclination apparatus, the controller controlling the inclination of the stage by the inclination apparatus.

A scanning method of the present invention comprises the steps of generating a predetermined scanning pattern to read out an optically readable medium, changing an emitting direction of the predetermined scanning pattern to a desired direction while maintaining the predetermined pattern, emitting the predetermined scanning pattern to the desired direction, and reading out light reflected from the medium based on the predetermined pattern.

An optical device of the present invention comprises an optical unit which generates a predetermined scanning pattern, emits the predetermined scanning pattern to an optically readable medium, and receives light reflected from the medium, and an inclinable stage which mounts an optical system at least necessary to generate the predetermined scanning pattern from among the optical unit.

Thus, the optical readers and scanning method of the present invention may change a scanning-pattern emitting direction while maintaining the predetermined scanning pattern.

Other objects and further features of the present invention will become readily apparent from the following description and accompanying drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to the accompanying drawings, a description will be given of barcode scanner10A of a first embodiment according to the present invention. Hereinafter, the same elements are designated by the same reference numerals, and a description thereof will be omitted. In addition, in the following description, barcode scanner10generalizes barcode scanners10A,10B, etc.

The barcode scanner10A of the present invention, formed as a rectangular parallel shaped module (housing12) emits a scanning pattern onto a barcode as a readable object through read window14in the housing12, receives light reflected from the barcode, and reads the barcode data. The housing12may includes a plurality of read windows or is formed to be bendable, as seen in barcode scanner IDE which will be described later with reference toFIG. 30.

The barcode scanner10A inFIG. 1includes optical unit100which generates a scanning pattern, emits it in a predetermined direction, and receives light reflected from a barcode, stage200which mounts the optical unit100, inclination apparatus300which inclines the stage200with the optical unit100, and CPU400which controls the optical unit100. Optionally, the CPU400may control the inclination apparatus300, but this embodiment will be described later as barcode scanner10C with reference toFIG. 18. The barcode scanner10A may further include interface part410for exchanging data with an external POS terminal, a display part420which informs an operator whether it has recognized validly barcode data, and speaker422, or the like.

As shown inFIG. 2, the optical unit100includes light source110, light collecting mirror120having, at a center thereof, reflection mirror130as a plane mirror part, polygon mirror140, and fixed mirror group150, and light receiving part160. This arrangement is merely one typical example of an optical unit. In addition, a size of each element is relatively exaggerated for description purposes. The optical unit100for use with the barcode scanner10of the present invention may broadly include, in addition to this structure, those optical units which emit a beam and scan a barcode; for instance, an optical unit which emits a beam from a polygon mirror directly onto a barcode without intervening fixed mirror group, and an optical unit which emits a beam from a light source to a polygon mirror without intervening a reflection mirror. In general, if there are provided a plurality of optical units100a plurality of stages200and inclination apparatuses300are provided accordingly.

The light source110generates a laser beam or infrared ray (simply refereed to 5 as “beam” hereinafter) and emits it toward (the reflection mirror130provided at the center of) the light collecting mirror120. The light source110may utilize a semiconductor laser, e.g., a He—Ne laser tube. The light source110is driven light control circuit112shown inFIG. 1that controls turning on/off of the beam. The light control circuit112is connected to and controlled by the CPU400. A solid line arrow inFIG. 2indicates a beam emitted from the light source110.

The light collecting mirror120has a concave mirror shape having circle window122at a center thereof. The reflection mirror130is set as a plane mirror at the circle window122. The light collecting mirror120is made of one resin molded product including concave mirror124and the reflection mirror130. Of course, the reflection mirror130may be made as a different member independent of the light collecting mirror120.

In this embodiment, the concave mirror124in the light collecting mirror120receives light which includes barcode data and has been reflected from the polygon mirror140, stops it down to a predetermined spot diameter, and reflects it to the light receiving part160. A broken line arrow from the light collecting mirror120to the light receiving part160inFIG. 2indicates the reflected light. Optionally, the light collecting mirror120may be substituted for by a collimeter lens having the similar functions (or a combination of the collimeter lens and a cylindrical lens etc.).

The reflection mirror130in the light collecting mirror120reflects a beam emitted from the light source110to the polygon mirror140. Optionally, the reflection mirror130may serve to reflect light reflected from the polygon mirror to the light receiving part160.

Optionally, as shown inFIG. 3, the reflection mirror130may be comprised of swing mirror134which is swingable around shaft132orthogonal to a rotational axis143of the polygon mirror140which will be described later. Swing of the reflection mirror130(134) generates a plurality of scanning patterns which are mutually shifted, improving the reading precision. The shift width of the scanning pattern is set to a value at least higher than the value (7 mm) defined in the laser safety standards, and it is designed that the shifted scanning patterns never go into operator's pupil(s).

As shown inFIGS. 1 through 5, the polygon mirror140has a plurality of reflection surfaces142and rotational axis143, and is connected to a motor144that rotates the polygon mirror140. The motor144is connected to angle detecting device146which detects a rotational angle of a motor shaft (not shown) of the motor144, and motor driving circuit148which drives the motor144. Optionally, magnet147and hole element149are provided to detect a home position (i.e., reference position) of the polygon mirror140. Either the magnet147or the hole element149rotates with the polygon mirror140, whereas the other stands still with the stage200.

The polygon mirror140reflects beam light reflected from the reflection mirror130to the fixed mirror group150, and reflects light including the barcode data reflected from the fixed mirror group150to the reflection mirror130. The desired number of reflection surfaces142may be provided, and each reflection surface142has a different inclination in the instant embodiment. For example, the polygon mirror140is formed as a square pillar for four reflection surfaces142, and a pentagonal pillar for five reflection surfaces142. The motor shaft (not shown) of the motor144is the same shaft as the rotational axis143of the polygon mirror140, and the polygon mirror140(or the respective reflection surfaces142) rotates around the rotational axis143.

The angle detecting device146and the motor driving circuit148are connected to and controlled by the CPU400. Any angle detecting means (for instance, a potentiometer) that has been known in the art is applicable to the angle detecting device146.

The fixed mirror group150includes a plurality of (e.g., five) stationary mirrors (or also called “scan mirrors”)152. The fixed mirror group150emits, as a scanning pattern, a beam light reflected from the polygon mirror140through the read window14to a barcode so as to scan it, and reflects light reflected by the barcode to the polygon mirror140. Since each reflection surface142of the polygon mirror140is inclined differently, one stationary mirror152emits a beam in a plurality of directions (for example, three directions for three inclined angles). When five stationary mirrors are used, as shown inFIGS. 2,4and5, the stationary mirrors152include a pair of outermost V mirrors154, a pair of H mirrors156adjacent to the V mirrors154, and one center Z mirror158. Beams reflected by these stationary mirrors152form a scanning pattern including V pattern155, H pattern, and Z pattern159above the read window14. Radiation of this scanning pattern onto a barcode above the read window14results in the reflected light including the barcode data.

The light receiving part160includes light receiving element162such as a pin photodiode, etc., and A/D converter part164. The light receiving element162receives light reflected from a barcode through the reflection mirror130which proceeds reverse to the beam and includes the barcode data, converts it into an analog signal, and then sends it to the A/D converter part164. The A/D converter part164, connected to the CPU400, converts the analog signal to a digital signal, and sends it to the CPU400.

A simulation has been previously conducted for the optical unit400before the unit is shipped so that optical noises become minimum and the light amount of the scanning pattern meet the laser safety standards (such as IEC and CDRH). Therefore, the optical unit10may generate a scanning pattern which always has an optimal reading precision and secures safety irrespective of the installation and usage environments.

The optical unit100is fixed onto the stage200which has a plate shape or any other arbitrary shape. The stage200is made of materials which have strength sufficient to support the optical unit100(such as an iron plate). The stage200does not have to mount all the elements of the optical unit100, and may mount only a minimum optical system necessary to emit a scan beam (e.g., the light source110, light collecting mirror120, reflection mirror130, polygon mirror140, and fixed mirror group150). Optionally, the stage200mounts such an optical system to receive reflected light of a scan beam (such as the light receiving element162). In any event, the stage200need not mount the light control circuit112, angle detecting device146, and motor driving circuit148, and A/D converter part164. Here, “a minimum optical system necessary to emit a scan beam” means an optical system which may maintain an optimal scanning pattern preset when the product is shipped. Therefore, it does not include inclination that breaks the preset optimal scanning pattern, for example, by independently inclining only the stationary mirror130. However, for example, in case of using a one-dimensional inclination mechanism which maintains an optical axis of a beam from the light source110, the light source110may be theoretically excluded from the stage200. As far as the light reflected from a barcode can be read, the light receiving element162may be removed from the stage200. If an element of the optical unit changes, for example, if a collimeter lens is used rather than the light collecting mirror120, :‘a minimum optical system necessary to emit a scan beam” must also change accordingly. Incidentally, the stage200may be processed so that it has part or all of the functions of the inclination apparatus300which will be described below.

The inclination apparatus300is mechanically connected to the stage200, and compatible with various types of inclinations, such as a one-dimensional inclination two-dimensional inclination, manual inclination, and automatic inclination. The automatic inclination by the CPU400will be described later with reference toFIG. 17. The inclination apparatus300includes inclination mechanism302which inclines the stage200, and securing mechanism304which secures the stage200at a predetermined inclined angle. Optionally, the inclination apparatus300further includes returning device306which returns the stage200to the horizontal state, and display308which notifies an operator of a direction and amount of the inclination. In the following description, the inclination apparatus300generalizes reference numerals300a,300b, etc., that are assigned to inclination apparatuses in the different embodiments. This generalization applies to the inclination mechanism and other elements.

The inclination mechanism302may be a one-dimensional inclination mechanism that one-dimensionally inclines the stage200, or a two-dimensional inclination mechanism that two-dimensionally inclines it. In the following description, the inclination mechanism302inclines the stage200by a mechanical action, but this does not exclude electric, magnetic and other actions. As described above, the inclination mechanism302may be inclined manually by an operator or automatically by the CPU400, and the automatic inclination will be discussed with reference toFIG. 17.

The one-dimensional inclination mechanism is one that inclines the stage200around a rotational axis that extends in a predetermined direction. An operator can incline the stage200directly or indirectly around the rotational axis by applying a moment to the rotational axis, the stage200or a member coupled with the stage200. Therefore, the one-dimensional inclination mechanism <<enerallv includes such a rotational axis and moment application means. The one-dimensional inclination mechanism has various modifications by types of the rotational axis and the moment application means.

A description will now be given of a one-dimensional inclination mechanism in which a rotational axis is made by support shaft310coupled to the stage200and an operator applies a moment directly onto the support shaft310via direction indicator dial312coupled to the support shaft310.

FIG. 6shows exemplary inclination apparatus300ahaving one-dimensional inclination mechanism302a. As illustrated, the support shaft310as a rotational axis is connected to lower surface202of the stage200while separated from the lower surface202by a predetermined distance, and supported rotatable with the stage200with respect to the housing12. A position and sectional shape of the support shaft310is not limited to those shown inFIG. 6. Therefore, the support shaft310may be connected to the stage200while penetrating almost the center of the stage200or may be connected to the bottom or side of the stage200. In other words, the rotational axis may be positioned in the stage200or spaced from the stage200.

FIG. 7is an exemplary connection between the support shaft310and the stage200that realizes the inclination mechanism shown inFIG. 6. As illustrated, the support shaft310is attached rotatably to the housing12via a pair of bearings311aand311b, and a pair of levers319aand319bare secured onto the support shaft310between the bearings311aand311b. These levers319aand319bare secured onto the lower surface202of the stage200. Therefore, the support shaft310is able to rotate together with the stage200via the levers319aand319bwith respect to the housing12. For purpose of illustrations, gear314inFIG. 6which will be described later and other elements are omitted inFIG. 7. Similarly, the bearings311aand311band the like are omitted inFIG. 6.

Any bearing known in the art (for example, a ball bearing) is applicable to the bearings311aand311b.

AlthoughFIG. 7shows that each of the levers319aand319bhas a semi-cylindrical shape having a predetermined width along the support shaft310, the shape thereof is not limited to it. Any desired shape may be selected in accordance with the interval to be spaced between the support shaft310and the stage200, and other conditions. The predetermined width is set by taking into account the strength necessary for achieving stable inclining actions between the support shaft310and the stage200. Therefore, levers319aand319bmay be made of members having different shapes and sizes. The number and positions of levers are not limited to those shown inFIG. 7. The lever may be part of the stage200, instead of forming an independent member.

As shown inFIGS. 6 and 7, the support shaft310penetrates the housing12at both ends thereof, and one end protrudes as protrusion310afrom the housing12and15engaged with the direction indicator dial312. The direction indicator dial312has any shape as far as it can surely function to indicate an inclined angle as stated below. InFIGS. 6 and 7, the direction indicator dial312has a sectional shape of a combination of a circle and a triangle.

In the initial state, the stage is set to be “no inclination” (horizontal), and the direction indicator dial312indicates 0° in scale313provided on the housing12. The scale313is omitted inFIGS. 6 and 7. Exemplary scale313is shown inFIG. 8. The scale313may be cut every five degrees, for example, and produced by a desired method. Alternatively, if a more precise angle is required to be indicated, a display that electrically responds to a rotation of the direction indicator dial312may be provided in addition to or instead of the scale313.

An operator may incline the stage200by an arbitrary angle by rotating the direction indicator dial312. When the stage200is inclined, the direction indicator dial312indicates the inclined angle on the scale313.

The inclination apparatus300ashown inFIG. 6includes securing mechanism304athat holds the stage200at the initial state and the inclined state after inclination5. The securing mechanism304amay secure the stage200by any known method. For example, referring toFIG. 6, the securing mechanism304amay be comprised of gear314which is connected coaxially to and rotatable with the support shaft310, and lock pin316which is connected to the housing12and movable between lock position A and retreat position B in hole317in the housing12. When the lock pin316is located at the retreat position B, an operator can rotate the direction indicator dial312. When the lock pin316is moved to the lock position A and engaged with the gear314, it can secure the gear314, thereby securing the support shaft310and the stage200at that inclination. In an attempt to secure a stable operation by setting as a normal state the lock state of the stage200, the lock pin316may be forced to the lock position A by a spring member etc. In this case, the operator moves the lock pin316to the retreat position B before inclining the stage200.

If the stage200needs to be returned to the initial state (horizontal state) after the lock pin316is released from fixation, a spring member (not shown) may be provided as return device306a. One end of the spring member is fixed onto the bottom of the housing12and the other end is connected to the lower surface202of the stage200.

The scale313provided at the side of the housing12and the direction indicator dial312serve as the display308of the inclination apparatus300a. An operator may always obtain optimal operations by memorizing the inclined angle and using it for the next setting.

The barcode scanner10A shown inFIG. 6may be used as a longitudinal type, as shown inFIG. 8. or as a lateral type as shown inFIG. 9, for example. An operator can obtain an inclined angle of the stage200optimal to him/her by simply adjusting the direction indicator dial312, irrespective of his/her height and experience. Therefore, the barcode scanner10A shown inFIGS. 6 and 7may change a pattern emitting direction in accordance with the installation and usage environments while maintaining the optimal pattern preinstalled at the time of shipping.

Referring toFIG. 6, although the rotational axis is made of the support shaft310which is an independent member, it is not necessary to constitute the rotational axis by an independent member when the stiffness of the stage200is utilized. For example,FIG. 10schematically shows inclination apparatus300bhaving one-dimensional inclination mechanism302b. In the inclination mechanism302a, one end of each of two support shafts320and322is fixed onto the bottom of the housing12and the other end thereof is rotatably attached to the lower surface202of the stage200by a hinge (not shown). A rotational axis corresponds to straight line325that connects joint321between the support shaft320and the stage200to joint323between the support shaft322and the stage200. Thus, the inclination mechanism302bdoes not include a rotational axis as an independent member. The support shafts320and322do not have to stand perpendicular to the stage200. The stage200is inclinable around the straight line325by moving up and down operating shaft326that is connected to the stage200apart from the straight line325.

The support shaft310, serving as a rotational axis, is a member independent of the stage200inFIG. 6. However, another (not shown) one-dimensional inclination mechanism may be adopted by processing part of the stage200into a pair of protrusions, and protruding these protrusions from the housing12to serve as a rotational axis. In this case, the one-dimensional inclination mechanism does riot contain a rotational axis as an independent member, but the stage200has this function instead.

The moment application means is not limited to the direction indicator dial312that directly applies a moment to the support shaft310. For example, rather than the direction indicator dial312, if operating shaft328is coupled to the stage200parallel to the support shaft310, as in inclination apparatus300cinFIG. 11, an operator may apply a moment to the stage200around the support shaft310by moving up and down in the drawing the operating shaft328which protrudes from the housing12. This case is similar to that ofFIG. 6, in that the stage200is rotatable around the support shaft310, but it is different fromFIG. 6in that the support shaft310does not necessarily have the end310awhich protrudes from the housing12. The hole16in the housing12in which the operating shaft328moves would be formed as an arc, but could have a different shape as the shape of the operating shaft328changes. Needless to say, a position of the operating shaft328is not limited to that illustrated.

Although the operating shaft328is a member independent of the stage200inFIG. 11, it is possible to process part of the stage200into a protrusion, and protrude the protrusion from the hole16in the housing12, making this serve as the operating shaft328. Therefore, in this case, the one-dimensional inclination mechanism does not include the moment application means, but the stage200has this function instead.

If the stage200has the functions of the rotational axis and the moment application means, the stage200may additionally have functions of the securing mechanism, returning device, display, omitting inclination device300inFIG. 1. Such barcode scanner10B is shown inFIG. 12.FIG. 18shows a case where the CPU400automatically controls such stage200.

FIG. 13shows inclination apparatus300dhaving another one-dimensional inclination mechanism302d. The inclination mechanism302dincludes plate support member330which is ennaaed with the lower surface202of the stage200at one end thereof, support shaft331as a rotational axis which penetrates through the stage200, and operating shaft332which is attached to the other end of the support member330.

The support shaft331is fixed onto the stage200, and supported rotatably by the housing12. The operating shaft332penetrates outside the housing12through arc17that is formed in the housing12. An operator may apply a moment to the support member330and the stage200by moving right and left in the drawing the operating shaft332. In this embodiment, the operating shaft332is spaced from the support shaft331of the stage200by a predetermined distance.

The support member330and the operating shaft332may be integrated into one member. The support member330is not limited to a plate-shaped member, but may be formed as an L-shaped rod so as to serve as the operating shaft332, omitting the operating shaft332. As stated, the stage200may have one or both of these functions. Processing part of the stage200may make the support shaft331. A position and shape of the support shaft331are not limited to those shown inFIG. 13, similar to the above embodiments.

The one-dimensional inclination mechanism may thus use, but is not limited to, any of the above concrete structures. A description will now be given of the inclination mechanism302as a two-dimensional inclination mechanism.

The two-dimensional inclination mechanism is one which broadly inclines the stage200two-dimensionally, but is not limited to two orthogonal axes. It is similar to the one-dimensional inclination mechanism in that an operator inclines the stage directly or indirectly by applying a moment to the stage200via an operating point that is located outside the housing12.

A description will now be given of inclination apparatus300ehaving two-dimensional inclination mechanism302ewhich inclines the stage200ain two-axes, with reference toFIGS. 14 and 15. The inclination mechanism302eincludes support shafts340and342, stage344, different from the stage200a, which mounts the optical unit100, direction indicator dial346engaged with the support shaft340, direction indicator dial348engaged with the support shaft342, hinge350which engages the stage200awith the stage344, spring member352, and cam354.

The support shaft340is coupled to the lower surface of the stage344by securing members356and358. As far as the support shaft340rotates together with the stage344, an arbitrary position and structure may be selected for the securing members356and358. For example, the securing members356and358may be comprised of the levers319aand319b, as shown inFIG. 7.

The stage344is coupled to the stage200aby the hinge350. As the support shaft340rotates, the stage344that is integrated with it rotates together. The stage200aalso rotates with the stage344around the support shaft340since the hinge350connects the stage200awith the stage344while prohibiting them from relatively rotating in a rotating direction of the support shaft340. Thereby, an operator may incline the stage200aaround the support shaft340by twisting the direction indicator dial346.

The stage200ais rotatable relative to the stage344by the hinge350(in direction C inFIG. 15). The direction C is orthogonal to a rotatable direction of the support shaft346. The stage200ais forced clockwise by the spring member352.

The support shaft342is connected to a top surface of the stage344by a securing member (not shown) similar to the securing members356and358. The cam354is coupled to and rotated with the support shaft342. The cam354is located between the hinge350and the spring member352, and contacts the lower surface202of the stage200a. As far as the cam354inclines the stage200awhen rotating with the support shaft342by a different height which corresponds to the rotational angle, its shape is not limited to the illustrated one. The cam354is formed as a cylindrical shape and the support shaft342is shifted from the center of the cylinder inFIG. 15, but it is apparent that the cam354may have a shape similar to the direction indicator dial348. Thereby, the operator may incline the stage200aaround the hinge350by a height corresponding to the rotational angle by twisting the direction indicator dial3485and rotating the support shaft342and the cam350.

Securing mechanism304e, returning device306e, and display306eof the inclination apparatus300eshown inFIGS. 14 and 15may utilize those shown inFIG. 6, and a description thereof will be omitted. The spring member352serves as the returning device around the support shaft342.

Next follows a description of a two-dimensional inclination mechanism that broadly two-dimensionally inclines the stage200. First, a description will now be given of inclination apparatus300fhaving two-dimensional inclination mechanism302fof the present invention, with reference toFIG. 16.FIG. 16schematically shows the inclination mechanism302f, omitting the optical unit100. The inclination mechanism302fincludes support member360located beneath the centroid of the stage200b, spring members362which keep the stage200bhorizontal, and compression means364which apply forces onto the stage200bfrom the top of the stage200b. InFIG. 16, the two-dimensional inclination mechanism302fhas four spring members362and four compression means364.

As far as the support member360properly serves as a fulcrum of inclination for the stage200b, it has an arbitrary shape. Referring toFIG. 16, a dent (not shown) is formed at the bottom of the stage200band the support member360has a conical shape having top361that is processed round so as to be partially engageable with the dent of the stage200b. Alternatively, the support member360may have a polygon pyramid or a sphere shape.

Each spring member362is connected to the bottom of the housing12at one end thereof, and the lower surface202of the stage202bat the other end thereof. The spring member362is adjusted so that no spring force applies to the stage200bat a horizontal state (initial state). The number and positions of springs are determined in accordance with the number and positions of compression means364so that the stage202bbecomes stable. Therefore, the spring member362may be provided below the compression means364. Alternatively, an elastic member other than the spring member362maybe provided under the stage200b, for example, an elastic sponge that envelops the support member360under the stage200b.

The compression means364apply compression or tension forces to corners of the stage200b, and may adopt any structure. It is not necessary to provide four spots as shown inFIG. 16. The compression means364is made, for example, by a link that is connected to the stage200bthrough a hinge. Referring toFIG. 16, working one or more compression means364would apply a moment around the top361of the support member360. For example, when the compression means364is made of a link, any method known in the art can be applicable to secure the link and indicate the moving amount. The spring member362serves as the returning device.

A description will now be given of the CPU400shown inFIG. 1. The CPU400is connected to the A/D converter part164of the optical unit100, the light control circuit112, the angle detecting device146, and the motor drive circuit148. The CPU400is also connected to the interface part410, the display part420, the speaker422and an external power source (not shown).

The CPU400includes a ROM, a RAM, a timer, an 1/0 controller, etc. (not shown), and runs based on a program stored in the ROM or RAM.

The CPU400controls the light control circuit112by a method known in the art. The CPU400can control each element so that it may enter an energy-saving mode when the timer (not shown) detects that the barcode scanner10has not been used for a long time.

The CPU400sends an angle signal to the angle detecting device146and the motor drive circuit148, thereby controlling a rotational angle of the motor144(and the reflection surfaces142of the polygon mirror140).

The CPU400receives a digital signal from the A/D converter part164of the light receiving part160and recognizes the barcode data. A barcode is recognized from data written down its top, middle, and end in a predetermined format. The CPU400judges that the data is valid when recognizing that the received digital data includes all of these data, and sends the data to a POS terminal via the interface part410. Simultaneously, the CPU400may switch on and off the green light on the display420, and beeps from the speaker422, notifying an operator that the data has been validly recognized.

On the other hand, the CPU400judges that the data is invalid when it could recognize only part of the data or when the data did not comply with the predetermined format. The CPU400then switches on and off the red light on the display420, and optionally gives an alarm sound from the speaker422. Thus, the CPU400notifies the operator of the invalid reading and prompts him/her to perform the reading over again. Incidentally, a description will be given later of control of the CPU400over the inclination apparatus300when the CPU400recognizes the part of barcode data.

Next follows a description of barcode scanner10C in which the CPU400automatically controls the inclination apparatus300, with reference toFIGS. 17 and 18. In this case, the CPU400controls the inclination apparatus300based on the program stored in the ROM or RAM (not shown). As shown inFIG. 18, the CPU400may control the stage200when the stage200serves as the inclination apparatus300, omitting the inclination apparatus300. However, this case would be easily understood from the description of control of the CPU400over the inclination apparatus300, and a description thereof will be omitted.

The CPU400in advance stores an optimal inclination angle for each operator in the ROM (not shown), and may control the inclination apparatus300based on it.

In this case, the CPU400obtains ID number data from the interface part410that the operator entered in the POS terminal, picks up inclined angle information corresponding to the ID from the ROM, and controls the inclination apparatus300based on that information. In this way, the operator may always obtain the optical unit100inclined at the optimal angle by simply entering his/her ID into the POS terminal.

When the CPU400does not store angle information for an operator, the CPU400conducts a simulation in accordance with a program stored in the ROM and detects the optimal angle information for the operator. There are several kinds of simulations, such as a method in which the operator repeats a trial reading, detects the optimal inclined angle, and enters it in the CPU400, and a method in which the CPU400automatically detect the inclined angle and stores it. Moreover, even after the CPU400obtains the optimal inclined angle for a certain operator, it may update the optimal inclined angle periodically (for example, when the number of reading errors exceeds a predetermined times per unit time) or when the operator desires so by conducting over again the former method or the latter automatic detecting method. Optionally, the CPU400does not store an optimal inclined angle every operator and always performs an automatic detection by the latter method.

When an operator detects the optimal inclined angle and enters it into the CPU400, the operator enters information of inclined direction that indicates whether a merchandise having a barcode moves from left to right or right to left viewed from the operator. Then, the operator makes the CPU400incline the stage200every predetermined angle (for example, five degrees) and enters the angle optimal to him/her into the CPU400. Optionally, the CPU400may automatically detect and store the optimal inclined angle based on the reading success rate. When an operator enters the inclined angle, he/she may utilize the POS terminal or a keyboard etc. connected to the barcode scanner10.

When the CPU400automatically detects an inclined angle, the CPU400may detect the optimal inclined angle by detecting a position of a stationary barcode or by detecting a path of a moving barcode. In either event, when information indicative of a moving direction of merchandise (i.e., whether it moves left to right or right to left) is entered previously, the CPU400would be able to detect the optimal inclined angle faster.

When the CPU400detects an inclined angle by detecting a position of a stationary barcode, an operator moves a barcode (or merchandise) to a reading area peculiar to him and stops the barcode there. There are several methods of detecting a position of the barcode.

First of all, there is a method in which the CPU400automatically and sequentially inclines the stage200by every predetermined angle (for example, five degrees) and detects an angle when it acquires light reflected from a barcode. In this case, the CPU400may adopt a two-stage searching method. The CPU400initially conducts a general search which uses a broad angle (for example, ten degrees) so as to roughly detect a barcode position, and the switches to a precise search when it detects part of the light reflected from the barcode, thereby detecting the precise position of the barcode.

A sensor may detect a barcode position. For example, as shown inFIG. 19, the barcode scanner10C has product detecting sensors366and indicator lamps368on the housing12. Needless to sav, positions and arrangements of the product detecting sensors366and the indicator lamps368are not limited to those shown inFIG. 19.

The product detecting sensors366are arranged in the longitudinal and lateral directions, covering the read window14at the top of the housing12, and their outputs are connected to the CPU400, The product detecting sensor366detects a shadow of merchandise and/or a barcode, and thereby detects its rough position. Any known sensor is applicable to the product detecting sensor366. The CPU400controls inclination by the inclination apparatus300based on a detection signal of the product detecting sensors366.

The indicator lamp368indicates a position of scanning pattern (or a reading area) emitted from the optical unit100on the inclined stage200, and informs an operator of it. The indicator lamp368turns on in accordance with an instruction from the CPU400. Thereby, an operator recognizes that a barcode should be approached to the reading area indicated by the indicator lamp368.

Where the CPU400detects an optimal inclined angle by detecting a moving path of a barcode, an operator is required to move a barcode (or actually a merchandise) along his moving path once or several times. The CPU400may detect the barcode moving path based on the detection signal of the product detecting sensors366, or it may detect the optimal inclined angle by making the inclination apparatus300incline the stage200randomly, and detecting the barcode moving path from the light reflected from the barcode at that time.

When the product detecting sensor366is used, there are provided a plurality of product detecting sensors366on the housing12. The CPU400may detect a barcode moving path by tracing the product detecting sensors366which respond to barcode's shadow which moves as the barcode moves. Referring toFIG. 20, a description will be given of an exemplary control method in which the CPU400detects the optimal inclined angle by detecting a barcode moving path, using the product detecting sensors366.

Initially, the CPU400judges whether or not the barcode scanner10C having the stage200at an inclined angle in an initial state (or operated state) could read a barcode (step702). Such a judgement is based on whether the CPU400or the POS terminal connected to it could understand the read barcode data.

If the barcode is normally read out, then the result is output to the POS terminal via the interface part410(step704), and the CPU400maintains the inclined angle at that time. In the step702, if the barcode cannot be read, the CPU400checks the inclined angle of the stage200by the inclination apparatus300(step706). Optionally, a step of judging whether the number of reading errors exceeds a predetermined times (for example, three times continuously) may be inserted between the steps702and706. In that case, only if the number of reading errors reaches the predetermined times, the procedure is fed to the step706, otherwise is fed back to the step702, prompting the operator to repeat the reading operation.

Next, the CPU400obtains information relating to the barcode moving path from the product detecting sensors366(step708), calculates the optimal inclined angle based on the it, and controls the inclination apparatus300, thereby modifying the current inclined angle to the optimal inclined angle (steps710and712). In this case, it is conceivable that the barcode moving path by the operator was accidentally abnormal to the operator, so the CPU400may prompt the operator to move the barcode several times, and calculate the optimal inclined angle from the averaged moving path.

Control of the inclination apparatus300is conducted, for example, by controlling driving of the motor370, which will be described with reference toFIG. 22. Thereafter, the barcode is read with the optimal inclined angle (step714), but optionally the CPU400may inform and/or indicate the operator after the step712before the step714that the optimal inclined angle has been set.

If the reading operation succeeds, the CPU400outputs the result to the POS terminal (step704), and if the reading operation fails, the CPU400prompts the operator to repeat the reading operation since the inclined angle has already been set to be optimal (step716).

A barcode moving path is also detectable by utilizing light reflected from the barcode. A description will now be given of the CPU400in this case. The scanning pattern emitted from the optical unit100sequentially moves in the space as the motor144rotates. When the scanning pattern properly goes across the entire surface of the barcode, the reading operation succeeds. However, when the scanning pattern goes across only part of the barcode, for example, the read data becomes incomplete. The CPU400may monitor this information momentarily, calculate a position of the scanning pattern which reads (even part of) data, and make the inclination of the stage200follow the calculation result.

For example, as shown inFIG. 4, a beam is emitted (as a scanning pattern) in three directions from one stationary mirror152as the polygon mirror140rotates and each reflection surface142changes an inclined angle. For instance, as shown inFIG. 21, a pair of V mirrors154generate V patterns155athrough155f, a pair of H mirrors156generate H patterns155fthrough155f, and one Z mirror158generates Z patterns159athrough159c. The generation is repeated, by the rotation of the polygon mirror140, in the order of155a,157f,159a,155d,157d,155b,157b,159b,155e,157e,155c,157c,159c,155f, and157fand a barcode is recognized in this order. Therefore, if the barcode data enters in the order of155d,155e, and155f, for example, the CPU400recognizes an area of the moving path is close to155dthrough155fand the moving direction is left to right inFIG. 21, Based on this information, the CPU400may generate a control signal and control the inclination apparatus300, Since the CPU400obtains an entry order of the barcode data in step708(for example, the order of155d,155eand155f) the control method in this case is similar to the procedure shown inFIG. 20.

Next, a description will now be given of an operation of the CPU400when the inclination mechanism302comprises the one-dimensional inclination mechanism shown inFIG. 22. The structure is similar to that inFIG. 7except for the automatic inclination, and a duplicate description will be omitted.

The one-dimensional inclination mechanism shown inFIG. 21includes motor370, gearbox371, motor drive circuit372which drives the motor370, support table373which supports the motor370and the gearbox371, potentiometer374as an angle detecting device which detects an inclined angle of the stage200, and support shaft310which is connected to and rotatable with the stage200and also connected directly or indirectly to and rotatable with the motor shaft (not shown) of the motor370. The motor drive circuit372and the potentiometer374are connected to and controlled by the CPU400. The CPU400obtains angular information of the stage200from the potentiometer374, and controls the motor drive circuit372based on this information.

The gearbox371serves to reduce a speed of the motor370and increase torque to be applied to the support shaft310. Thereby, even the small motor370can secure the torque enough to incline the stage200.

It is understood that when the stage200serves as the support shaft310the motor370is directly connected to the stage200.

In general, no securing device which secures the support shaft310(and the stage200) (such as, the gear314and the lock pin316shown inFIG. 6) is required in the inclination apparatus300g(inclination mechanism302g) shown inFIG. 22. This is because that the support shaft310is connected to the motor shaft (not shown) of the25motor370, and the motor shaft and the support shaft310stops, when the motor drive circuit372stops electrifying the motor, in that state. This is common to the following two-dimensional inclination mechanisms having similar structures.

A return to a predetermined position is realized simply by a program (which reversely rotating the motor370, for example) stored in the CPU400or the motor drive circuit372in the inclination mechanism302gshown inFIG. 22. Therefore, no5spring member is required to connect the lower surface202of the stage200to the bottom of the housing12. This is common to the following two-dimensional inclination mechanisms having similar structures.

No display is generally required in the inclination mechanism302ginFIG. 22. The primary purpose of the display is to notify the operator of the inclined angle for use with the next operation, but the CPU400memorizes the optimal inclined angle for the next operation for each operator. As a result, the operator does not have to memorize it, and the direction indicator dial312is not required generally. However, if necessary, the angle detecting device374and/or an angle display connected to the CPU400may be independently provided. Such an angle display is useful for those 15 operators who would like to actually reconfirm his/her optimal inclined angle. This is common to the following two-dimensional inclination mechanisms having similar structures.

The potentiometer374is connected to variable resistor375via lead line376aand376b. The variable resistor375may apply resistance responsive to the rotational angle of the support shaft310to the potentiometer375. When the input voltage is made constant (for example, DC 5V), the resistance value of the variable resistor375can be detected by measuring the output voltage, whereby the rotational angle of the support shaft310can be detected. The motor drive circuit372serves as the moment application means.

Next, referring toFIG. 23, a description will be given of inclination apparatus300h(inclination mechanism302h) which is an automatic inclination version of the inclination apparatus300bshown inFIG. 10. The inclination mechanism302hfurther includes, in addition to the elements of the inclination mechanism302b, angle detecting device374which detects an inclined angle of the stage200, moving device376which moves the operating shaft326, and drive device378which drives the moving device376. The moving device376and the drive device378may broadly utilize any known device in the art. For example, a motor which attaches a cam to the motor shaft is used for the moving device376and a motor drive circuit is used for the drive device378. In this case, the CPU400may incline the stage200by the predetermined angle by controlling a moving distance of the operating shaft326(which is expressed by the rotational angle of the motor shaft).

As shown inFIG. 11, where the operating shaft328is provided, the CPU400moves the operating shaft328up and down. The control method of the moving distance of the operating shaft328is similar to those for the moving device376and the drive device378. This is also similar to a case where the support member330and the operating shaft332are provided as shown inFIG. 13.

Referring toFIG. 24, a description will now be given of inclination apparatus300i(inclination mechanism302i) which is an automatic inclination version of the inclination apparatus300eshown inFIG. 14. The inclination mechanism302iincludes, instead of direction indicators346and348, in the elements of the inclination mechanism302e, motors380and381, motor drive circuits382and383which drive the motors380and381, angle detecting device384which detects an inclined angle of the stage200a, and angle detecting device385which detects an inclined angle of the stage344. The support shaft340is connected directly or indirectly to and rotatabie with the motor shaft (not shown) of the motor380, whereas the support shaft342is connected directly or indirectly to and rotatabie with the motor shaft (not shown) of the motor381. The motor drive circuits382and383and the angle detecting devices384and385are connected to and controlled by the CPU400. The CPU400obtains angular information of the stages200aand344from the angle detecting devices384and385, and controls the motor drive circuits382and383based on this information.

When the stage200aand/or the stage344serve as the support shafts340and5342, the motors380and381are connected to the stages200aand344, Each of the angle detecting devices384and385is similar to the angle detecting device374. A method for the CPU400to obtain the optimal inclined angle is basically the same as that for the one-dimensional inclination mechanism, but it is necessary to heed that the rotary shaft of the stage200ais not the support shaft342but the hinge350(seeFIG. 15) inFIG. 24. Therefore, the CPU400must, in advance, memorize the relationship between the rotational angle of the support shaft342and the inclined angle of the stage200a.

In automatically controlling the inclination apparatus300fshown inFIG. 16, the CPU400may control an inclination angle of the stage200bby controlling a moving distance of the compression means364. The moving distance of the compression means364is similarly controlled, as shown inFIG. 23, for example, by the angular detecting device374connected to the stage200b, the moving device376connected to the compression means364, and the drive device378connected to the moving device376.

As briefly shown inFIG. 25, which omits the optical unit100, inclination apparatus300j(inclination mechanism302j) may include four support members390which are hinged at the lower surface202cof the stage200c. Four joints between these four support members390and the stage200ccorrespond to corners of a square or a rectansle. The stage200cmay be inclined in an arbitrary direction by simultaneously moving up or down the adjacent two support members390. The CPU400similarly controls a moving distance of the compression means364, as shown inFIG. 23, for example, by using the angular detecting device374connected to the stage200c, the moving devices376connected to each support member390, and the drive device378connected to each moving device376.

Optionally, even when the CPU400automatically controls the inclination apparatus300, an operator may change the setting by manipulating a keyboard near the barcode scanner10. This is especially useful to avoid double reading when the barcode scanner10ainFIG. 27is used.

Irrespective of the manual and automatic adjustments, the inclinable angle may be restricted so that a scanning pattern does not go into eyes of an operator and/or a customer who stand at a predetermined position and/or the stage200(or the optical unit100) does not collide with the inner wall of the housing12. The restriction to the rotatable range of the rotational axis is easily available, for example, by a mechanical action or a program in a ROM (not shown) in the CPU400. The mechanical restriction is available as shown inFIG. 26, for example, where pin315provided on the gear314coaxial to the support shaft310inFIG. 6is allowed to move in cutout19in the housing12. When the pin315rotates clockwise inFIG. 26, its movement is restricted by end19bof the cutout19. When the pin315rotates counterclockwise inFIG. 26, its movement is restricted by end19bof the cutout19. For example, in order to prevent the stage200inFIG. 6from colliding with the housing12as a result of inclination, a buffer cushion may be provided inside the housing12.

A description will now be given of concrete actions of the barcode scanners10A through10D of the present invention. In the following discussion, the barcode scanner10generalizes the barcode scanners10A through10D and direction indicator dials and other elements are omitted in the drawings0.

FIG. 27shows the barcode scanner10installed on post502a. Keyboard500ais provided next to the barcode scanner10. The barcode scanner10is connected to POS terminal504. The barcode scanner10shown inFIG. 27is used as a longitudinal type. The height of the post502ais adjustable depending upon operator's height. In operation, the operator picks up a merchandise out of a shopping basket that he/she has placed under the barcode scanner10, makes the barcode scanner10read the barcode, and returns the merchandise to the basket. However, if the basket is placed in the scanning-pattern emitting direction of the barcode scanner10and has merchandise with barcodes, there is a risk of double reading. As shown inFIG. 29, a method in which another basket is prepared and two baskets are placed at both ends of the barcode scanner10may avoid the double reading, but this method is restricted if the cashier table is not wide enough to place two baskets. Accordingly, the operator changes the inclined angle of the stage200by a mechanical operation or entry through keyboard500aso that the basket may be placed outside the reading area of the scanning pattern.

In use, the operator twists the direction indicator dial (not shown) or enters his/her ID through the keyboard50( )a, whereby he/she can obtain the optimal inclined angle. In order to set a new inclined angle or change the current inclined angle, the operator conducts the aforementioned simulation. The scanning pattern preinstalled at the time of shipping in a factory is maintained even when the optical unit100is inclined, securing highly reliable reading operations. The scanning pattern meets the laser safety standards, securing highly safe reading. A longitudinal barcode scanner may be conveniently used as a lateral barcode scanner after the store-refurbishing etc. simply by changing an inclined angle of the stage200.

FIG. 28shows the barcode scanner10that is embedded into the cashier table and used as a lateral type. An operator stands at a front side inFIG. 28and jumps a merchandise from left to right while making the intervening barcode scanner10read a barcode on the merchandise. This drawing shows a typical example of the barcode scanner10of the present invention. An operator may advantageously stand at the opposite side inFIG. 28after the store-refurbishing etc. and jump a merchandise from right to left simply by changing an inclined angle of the stage200.

The barcode scanner10shown inFIG. 29is also installed on post502b, but the post502bis not adjustable in height. Keyboard500bis located on the barcode scanner10, and the cashier table has a room for two baskets. This drawing also shows one of the most typical examples of the barcode scanner10of the present invention.

FIGS. 28 and 29each have similar effects to those ofFIG. 27.

Referring toFIG. 30, a description will now be given of barcode scanner (two-faced scanner)10E as one example of multi-faced scanners of the present invention. The multi-faced scanners are those barcode scanners which have a plurality of read windows on the housing. The two-faced scanners are those barcode scanners which have two read windows, and some have bendable two parts each having a read window. The two-faced scanner10E shown inFIG. 30has bending angle ct as an obtuse angle, but the barcode scanner10of the present invention is applicable to one which has the bending angle cc of an approximately right angle as shown inFIG. 31.

As the two-faced scanner10E emits scanning patterns from two scanner parts602and604, and scans a barcode from multiple directions, thus providing a reading precision greater than the single-faced scanner. More specifically, the two-faced scanner10E may improve the reading precision by passing a barcode through an optimal reading area (sweet spot S) near foci (a point where a beam diameter becomes minimum) of two scanning patterns emitted from these two scanner parts602and604.

Even though a barcode passes outside the sweet spot S those barcodes which have wide bar intervals, like a barcode printed on a relatively large merchandise (e.g. a six-roll pack toilet paper) are possibly readable. However, a barcode having narrow bar intervals put on a relatively small merchandise is not always readable properly. A two-faced scanner may keep the sweet spot S wider than usual scanners.

The two-faced scanner10E of the present invention has two scanner parts602and604which are bendable at joint601, guide indicator part606and switch608attached to the scanner part602, a pair of reading direction indicators610attached to the scanner604, and arrow mark612which indicates the bending angle α between the scanner parts602and604, and scale614.

In this way, the two-faced scanner10E is variable in bending angle α. Optionally, the bending angle a may be fixed to the predetermined value and made invariable. The scanner part602and/or the scanner part604may have a collimeter lens etc., if necessary, so that an emitted beam has a focus in the sweet spot S.

An operator changes the scanning-pattern emitting directions of the scanner parts602and604in accordance with the bending angle α, changing a position of the sweet spot S. The operator sets the bending angle α to an experientially-determined optimal angle, confirming a value on the scale614indicated by the arrow mark612.

Next follows a description of a relationship between the scanning-pattern emitting direction of the scanner part602and the bending angle α. Referring toFIG. 32, the scanner part602has a linkage including movable arm616and fixed arm619. The movable arm616includes end617which is rotatably connected to the stage200which mounts the optical unit100, and fixed end618which is rotatable relative to the scanner part602. On the other hand, the fixed arm619is fixed onto the side of the stage200, and includes end620which is connected to the end617of the movable arm616and the stage200, and fixed end621which is rotatable relative to the scanner part602. The movable arm616moves in an arrow direction inFIG. 32as the scanner part602moves relative to the scanner part604so that the bending angle α may increase. Thereby, the ends617and620, the stage200, and the optical unit100rotate counterclockwise around the fixed ends618and621as fulcrums. Therefore, as the bending angle α changes, the scanning-pattern emitting direction of the scanner part602changes accordingly.

For example, the two-faced scanner inFIG. 31enables the scanner parts602and604to emit scanning patterns in directions perpendicular to the read windows603and605, respectively. Therefore, as shown inFIG. 33, the sweet spot S is formed near a position where focus distance (or optimal depth) L from the scanner part604is L1. On the other hand, in the two-faced scanner inFIG. 29, the scanner part602emits scanning pattern at acute angle with respect to the read window603. Therefore, as shown inFIG. 33, the sweet spot S is formed near a position where a focus distance L from the scanner part604is L2. Small L (e.g., L=L1) is used to read small barcodes printed on a small merchandise, whereas large L (e.g., L=L2) is used to read large barcodes printed on a large merchandise. For example, in an attempt to read out a barcode printed on a six-roll pack toilet paper, if L is set to be L1, the merchandise collides with the scanner part602and cannot pass through the sweet spot S. When a barcode is located at the sweet spot S, two beams hit the barcode, whereby they are reflected and scattered. The reflected light then returns to the optical unit100in a path reverse to the scan light.

As shown inFIG. 35, the scanner parts602and604each generally correspond to one of the barcode units10A through10D. A variation which simplifies a structure is available; for instance, one CPU400may control both scanner parts602and604. Thus, even after the bending angle << is determined, and the scanning-pattern emitting direction of the scanner part602is determined by the linkage shown inFIG. 31, the stage200(and optical unit100) can be changed in inclined angle, of course.

The guide indicator part606inFIG. 30indicates a set value of the bendin” angle a, a size of merchandise corresponding to the set value (for example “L”, “M”, and “S”), an image which expresses the reading area, information of whether the reading has been succeeded, information of the read merchandise (such as, price),5shopping information, manipulation information, breakdown information of each part, and the like. The switch608may switch these information.

The guide indicator part606primarily serves to improve a working efficiency by providing an optimal manipulation to an inexperienced operator. Thereby, the operator may secure the optimal manipulation by adjusting the bending angle α, changing the inclined angle of the stage200, and the like. Alternatively, the guide indicator part606may be located at a position where a customer and the operator both can easily see it, for example, at the top of the scanner part602. Thus, the guide indicator part606can be used to improve service to customers, for example, to have the customer confirm the price of the shopped goods, to provide shopping information (for example, sales information) to the customer, etc.

The guide indicator part606is provided with the scanner part602, but may be formed as a different unit from the scanner part602or integrated with the keyboard unit. The guide indicator part606is made of an LED or LCD which indicate only letters, or a TFT or plasma display which can indicate images, and the like.

The reading direction indicator610includes arrow marks. The arrow mark corresponding to a merchandise moving direction turns on. For example, as shown inFIG. 36, where a merchandise moves right to left, the right arrow mark which indicates the moving direction turns on, and the scanner part604emits the scanning pattern in the right direction.

Further, the present invention is not limited to these preferred embodiments, but various variations and modifications may be made without departing from the scope of the invention. For example, the barcode scanner of the present invention is not limited to those fixed onto a cashier table and the like, but is broadly applicable to hand-held type barcode scanners in which an operator approaches an optical reading part to a barcode, and optical readers which emit a scanning pattern to an optically readable medium.

According to the optical reader of the present invention, the variable emitting direction of the scanning pattern enables uniform manufacturing of the optical reader, without distinction of longitudinal and lateral types and barcode moving directions. An operator may adjust an emitting direction in accordance with his/her height and experience to obtain prompt reading operations without practicing manipulations necessary for the conventional devices. Moreover, the maintained optimal scanning pattern provides a high reading reliance and meets the laser standards safely.