Abstract:
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 freely changeable.

Description:
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&#39;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 merchandises 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. Disadvantageously, each operator must adjust a barcode moving path and spend a long 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 pattern that has a high barcode-reading reliability. The optimal scanning pattern is one determined 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&#39;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. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a block diagram showing a principle of a barcode scanner of a first embodiment according to the present invention. 
     FIG. 2 shows an arrangement of essential part of a typical optical unit for use with the barcode scanner according to the present invention. 
     FIG. 3 is a perspective view of essential part of a modified example of a reflection mirror of the optical unit shown in FIG.  2 . 
     FIG. 4 is a side view of essential part of arrangement between a polygon mirror and a fixed mirror group in the optical unit shown in FIG.  2 . 
     FIG. 5 is a perspective view of essential part of arrangement between a polygon mirror and a fixed mirror group in the optical unit shown in FIG.  2 . 
     FIG. 6 is a transparent perspective view of essential part of one example of inclination apparatus of the barcode scanner shown in FIG.  1 . 
     FIG. 7 is a partially sectional and perspective view showing essential part of exemplary connections that realize the inclination apparatus shown in FIG.  6 . 
     FIG. 8 is a perspective view for explaining an effect of the barcode scanner shown in FIG.  6 . 
     FIG. 9 is a perspective view for explaining another effect of the barcode scanner shown in FIG.  6 . 
     FIG. 10 is a schematic perspective view of a modified example of the inclination apparatus shown in FIG.  6 . 
     FIG. 11 is a transparent perspective view of essential part of another modified example of the inclination apparatus shown in FIG.  6 . 
     FIG. 12 is a block diagram showing a principle of a barcode scanner of a second embodiment according to the present invention. 
     FIG. 13 is a transparent perspective view of essential part showing still another modified example of the inclination apparatus shown in FIG.  6 . 
     FIG. 14 is a perspective view of essential part showing another example of the inclination apparatus of the barcode scanner shown in FIG.  1 . 
     FIG. 15 is a side view of the inclination apparatus shown in FIG.  14 . 
     FIG. 16 is a schematic perspective view of a modified example of the inclination apparatus shown in FIG.  14 . 
     FIG. 17 is a block diagram showing a principle of a barcode scanner of a third embodiment according to the present invention. 
     FIG. 18 is a block diagram showing a principle of a barcode scanner of a fourth embodiment according to the present invention. 
     FIG. 19 is a perspective view of product detecting sensors applicable to the barcode scanners shown in FIGS. 17 and 18. 
     FIG. 20 is a flowchart of control procedures of a CPU shown in FIGS. 17 and 18. 
     FIG. 21 shows a scanning pattern emitted from a read window. 
     FIG. 22 is a diagram for explaining automatic control of the inclination apparatus shown in FIG.  6 . 
     FIG. 23 is a diagram for explaining automatic control of the inclination apparatus shown in FIG.  10 . 
     FIG. 24 is a diagram for explaining automatic control of the inclination apparatus shown in FIG.  14 . 
     FIG. 25 is a diagram for explaining automatic control of an inclination apparatus different from the inclination apparatus in FIG.  23 . 
     FIG. 26 is a plane view for explaining an example of mechanical restriction to an inclined angle of the inclination apparatus shown in FIG.  6 . 
     FIG. 27 is a view for explaining a concrete effect of the barcode scanner according to the present invention. 
     FIG. 28 is another view for explaining a concrete effect of the barcode scanner according to the present invention. 
     FIG. 29 is still another view for explaining a concrete effect of the barcode scanner according to the present invention. 
     FIG. 30 is a schematic perspective view of a barcode scanner (two-faced scanner) of a fifth embodiment according to the present invention. 
     FIG. 31 is a schematic perspective view of the barcode scanner shown in FIG. 30 in which a bending angle is a right angle. 
     FIG. 32 is a side view showing a relationship between a bending angle and an emitting direction of a scanning pattern in the barcode scanner in FIG.  30 . 
     FIG. 33 is a side view for explaining a sweet spot of the barcode scanner shown in FIG.  31 . 
     FIG. 34 is a side view for explaining a sweet spot of the barcode scanner shown in FIG.  30 . 
     FIG. 35 is a transparent perspective view of essential part showing an inner structure of the barcode scanner shown in FIG.  30 . 
     FIG. 36 is a top view for explaining a reading direction indicator of the barcode scanner shown in FIG.  30 . 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to the accompanying drawings, a description will be given of barcode scanner  10 A 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 scanner  10  generalizes barcode scanners  10 A,  10 B, etc. 
     The barcode scanner  10 A of the present invention, formed as a rectangular parallel shaped module (housing  12 ), emits a scanning pattern onto a barcode as a readable object through read window  14  in the housing  12 , receives light reflected from the barcode, and reads the barcode data. The housing  12  may includes a plurality of read windows or is formed to be bendable, as seen in barcode scanner  10 E which will be described later with reference to FIG.  30 . 
     The barcode scanner  10 A in FIG. 1 includes optical unit  100  which generates a scanning pattern, emits it in a predetermined direction, and receives light reflected from a barcode, stage  200  which mounts the optical unit  100 , inclination apparatus  300  which inclines the stage  200  with the optical unit  100 , and CPU  400  which controls the optical unit  100 . Optionally, the CPU  400  may control the inclination apparatus  300 , but this embodiment will be described later as barcode scanner  10 C with reference to FIG.  18 . The barcode scanner  10 A may further include interface part  410  for exchanging data with an external POS terminal, a display part  420  which informs an operator whether it has recognized validly barcode data, and speaker  422 , or the like. 
     As shown in FIG. 2, the optical unit  100  includes light source  110 , light collecting mirror  120  having, at a center thereof, reflection mirror  130  as a plane mirror part, polygon mirror  140 , and fixed mirror group  150 , and light receiving part  160 . 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 unit  100  for use with the barcode scanner  10  of 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 units  100 , a plurality of stages  200  and inclination apparatuses  300  are provided accordingly. 
     The light source  110  generates a laser beam or infrared ray (simply refereed to as “beam” hereinafter) and emits it toward (the reflection mirror  130  provided at the center of) the light collecting mirror  120 . The light source  110  may utilize a semiconductor laser, e.g., a He—Ne laser tube. The light source  110  is driven light control circuit  112  shown in FIG. 1 that controls turning on/off of the beam. The light control circuit  112  is connected to and controlled by the CPU  400 . A solid line arrow in FIG. 2 indicates a beam emitted from the light source  110 . 
     The light collecting mirror  120  has a concave mirror shape having circle window  122  at a center thereof. The reflection mirror  130  is set as a plane mirror at the circle window  122 . The light collecting mirror  120  is made of one resin molded product including concave mirror  124  and the reflection mirror  130 . Of course, the reflection mirror  130  may be made as a different member independent of the light collecting mirror  120 . 
     In this embodiment, the concave mirror  124  in the light collecting mirror  120  receives light which includes barcode data and has been reflected from the polygon mirror  140 , stops it down to a predetermined spot diameter, and reflects it to the light receiving part  160 . A broken line arrow from the light collecting mirror  120  to the light receiving part  160  in FIG. 2 indicates the reflected light. Optionally, the light collecting mirror  120  may 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 mirror  130  in the light collecting mirror  120  reflects a beam emitted from the light source  110  to the polygon mirror  140 . Optionally, the reflection mirror  130  may serve to reflect light reflected from the polygon mirror to the light receiving part  160 . 
     Optionally, as shown in FIG. 3, the reflection mirror  130  may be comprised of swing mirror  134  which is swingable around shaft  132  orthogonal to a rotational axis  143  of the polygon mirror  140  which will be described later. Swing of the reflection mirror  130  ( 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&#39;s pupil(s). 
     As shown in FIGS. 1 through 5, the polygon mirror  140  has a plurality of reflection surfaces  142  and rotational axis  143 , and is connected to a motor  144  that rotates the polygon mirror  140 . The motor  144  is connected to angle detecting device  146  which detects a rotational angle of a motor shaft (not shown) of the motor  144 , and motor driving circuit  148  which drives the motor  144 . Optionally, magnet  147  and hole element  149  are provided to detect a home position (i.e., reference position) of the polygon mirror  140 . Either the magnet  147  or the hole element  149  rotates with the polygon mirror  140 , whereas the other stands still with the stage  200 . 
     The polygon mirror  140  reflects beam light reflected from the reflection mirror  130  to the fixed mirror group  150 , and reflects light including the barcode data reflected from the fixed mirror group  150  to the reflection mirror  130 . The desired number of reflection surfaces  142  may be provided, and each reflection surface  142  has a different inclination in the instant embodiment. For example, the polygon mirror  140  is formed as a square pillar for four reflection surfaces  142 , and a pentagonal pillar for five reflection surfaces  142 . The motor shaft (not shown) of the motor  144  is the same shaft as the rotational axis  143  of the polygon mirror  140 , and the polygon mirror  140  (or the respective reflection surfaces  142 ) rotates around the rotational axis  143 . 
     The angle detecting device  146  and the motor driving circuit  148  are connected to and controlled by the CPU  400 . Any angle detecting means (for instance, a potentiometer) that has been known in the art is applicable to the angle detecting device  146 . 
     The fixed mirror group  150  includes a plurality of (e.g., five) stationary mirrors (or also called “scan mirrors”)  152 . The fixed mirror group  150  emits, as a scanning pattern, a beam light reflected from the polygon mirror  140  through the read window  14  to a barcode so as to scan it, and reflects light reflected by the barcode to the polygon mirror  140 . Since each reflection surface  142  of the polygon mirror  140  is inclined differently, one stationary mirror  152  emits a beam in a plurality of directions (for example, three directions for three inclined angles). When five stationary mirrors are used, as shown in FIGS. 2,  4  and  5 , the stationary mirrors  152  include a pair of outermost V mirrors  154 , a pair of H mirrors  156  adjacent to the V mirrors  154 , and one center Z mirror  158 . Beams reflected by these stationary mirrors  152  form a scanning pattern including V pattern  155 , H pattern, and Z pattern  159  above the read window  14 . Radiation of this scanning pattern onto a barcode above the read window  14  results in the reflected light including the barcode data. 
     The light receiving part  160  includes light receiving element  162  such as a pin photodiode, etc., and A/D converter part  164 . The light receiving element  162  receives light reflected from a barcode through the reflection mirror  130  which 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 part  164 . The A/D converter part  164 , connected to the CPU  400 , converts the analog signal to a digital signal, and sends it to the CPU  400 . 
     A simulation has been previously conducted for the optical unit  400  before 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 unit  10  may generate a scanning pattern which always has an optimal reading precision and secures safety irrespective of the installation and usage environments. 
     The optical unit  100  is fixed onto the stage  200  which has a plate shape or any other arbitrary shape. The stage  200  is made of materials which have strength sufficient to support the optical unit  100  (such as an iron plate). The stage  200  does not have to mount all the elements of the optical unit  100 , and may mount only a minimum optical system necessary to emit a scan beam (e.g., the light source  110 , light collecting mirror  120 , reflection mirror  130 , polygon mirror  140 , and fixed mirror group  150 ). Optionally, the stage  200  mounts such an optical system to receives reflected light of a scan beam (such as the light receiving element  162 ). In any event, the stage  200  need not mount the light control circuit  112 , angle detecting device  146 , and motor driving circuit  148 , and A/D converter part  164 . 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 mirror  130 . However, for example, in case of using a one-dimensional inclination mechanism which maintains an optical axis of a beam from the light source  110 , the light source  110  may be theoretically excluded from the stage  200 . As far as the light reflected from a barcode can be read, the light receiving element  162  may be removed from the stage  200 . If an element of the optical unit changes, for example, if a collimeter lens is used rather than the light collecting mirror  120 , “a minimum optical system necessary to emit a scan beam” must also change accordingly. Incidentally, the stage  200  may be processed so that it has part or all of the functions of the inclination apparatus  300  which will be described below. 
     The inclination apparatus  300  is mechanically connected to the stage  200 , 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 CPU  400  will be described later with reference to FIG.  17 . The inclination apparatus  300  includes inclination mechanism  302  which inclines the stage  200 , and securing mechanism  304  which secures the stage  200  at a predetermined inclined angle. Optionally, the inclination apparatus  300  further includes returning device  306  which returns the stage  200  to the horizontal state, and display  308  which notifies an operator of a direction and amount of the inclination. In the following description, the inclination apparatus  300  generalizes reference numerals  300   a ,  300   b , etc., that are assigned to inclination apparatuses in the different embodiments. This generalization applies to the inclination mechanism and other elements. 
     The inclination mechanism  302  may be a one-dimensional inclination mechanism that one-dimensionally inclines the stage  200 , or a two-dimensional inclination mechanism that two-dimensionally inclines it. In the following description, the inclination mechanism  302  inclines the stage  200  by a mechanical action, but this does not exclude electric, magnetic and other actions. As described above, the inclination mechanism  302  may be inclined manually by an operator or automatically by the CPU  400 , and the automatic inclination will be discussed with reference to FIG.  17 . 
     The one-dimensional inclination mechanism is one that inclines the stage  200  around a rotational axis that extends in a predetermined direction. An operator can inclines the stage  200  directly or indirectly around the rotational axis by applying a moment to the rotational axis, the stage  200  or a member coupled with the stage  200 . Therefore, the one-dimensional inclination mechanism generally 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 shaft  310  coupled to the stage  200  and an operator applies a moment directly onto the support shaft  310  via direction indicator dial  312  coupled to the support shaft  310 . 
     FIG. 6 shows exemplary inclination apparatus  300   a  having one-dimensional inclination mechanism  302   a . As illustrated, the support shaft  310  as a rotational axis is connected to lower surface  202  of the stage  200  while separated from the lower surface  202  by a predetermined distance, and supported rotatable with the stage  200  with respect to the housing  12 . A position and sectional shape of the support shaft  310  is not limited to those shown in FIG.  6 . Therefore, the support shaft  310  may be connected to the stage  200  while penetrating almost the center of the stage  200  or may be connected to the bottom or side of the stage  200 . In other words, the rotational axis may be positioned in the stage  200  or spaced from the stage  200 . 
     FIG. 7 is an exemplary connection between the support shaft  310  and the stage  200  that realizes the inclination mechanism shown in FIG.  6 . As illustrated, the support shaft  310  is attached rotatably to the housing  12  via a pair of bearings  311   a  and  311   b , and a pair of levers  319   a  and  319   b  are secured onto the support shaft  310  between the bearings  311   a  and  311   b . These levers  319   a  and  319   b  are secured onto the lower surface  202  of the stage  200 . Therefore, the support shaft  310  is able to rotate together with the stage  200  via the levers  319   a  and  319   b  with respect to the housing  12 . For purpose of illustrations, gear  314  in FIG. 6 which will be described later and other elements are omitted in FIG.  7 . Similarly, the bearings  311   a  and  311   b  and the like are omitted in FIG.  6 . 
     Any bearing known in the art (for example, a ball bearing) is applicable to the bearings  311   a  and  311   b.    
     Although FIG. 7 shows that each of the levers  319   a  and  319   b  has a semi-cylindrical shape having a predetermined width along the support shaft  310 , 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 shaft  310  and the stage  200 , and other conditions. The predetermined width is set by taking into account the strength necessary for achieving stable inclining actions between the support shaft  310  and the stage  200 . Therefore, levers  319   a  and  319   b  may be made of members having different shapes and sizes. The number and positions of levers are not limited to those shown in FIG.  7 . The lever may be part of the stage  200 , instead of forming an independent member. 
     As shown in FIGS. 6 and 7, the support shaft  310  penetrates the housing  12  at both ends thereof, and one end protrudes as protrusion  310   a  from the housing  12  and engaged with the direction indicator dial  312 . The direction indicator dial  312  has any shape as far as it can surely function to indicate an inclined angle as stated below. In FIGS. 6 and 7, the direction indicator dial  312  has 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 dial  312  indicates 0° in scale  313  provided on the housing  12 . The scale  313  is omitted in FIGS. 6 and 7. Exemplary scale  313  is shown in FIG.  8 . The scale  313  may 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 dial  312  may be provided in addition to or instead of the scale  313 . 
     An operator may incline the stage  200  by an arbitrary angle by rotating the direction indicator dial  312 . When the stage  200  is inclined, the direction indicator dial  312  indicates the inclined angle on the scale  313 . 
     The inclination apparatus  300   a  shown in FIG. 6 includes securing mechanism  304   a  that holds the stage  200  at the initial state and the inclined state after inclination. The securing mechanism  304   a  may secure the stage  200  by any known method. For example, referring to FIG. 6, the securing mechanism  304   a  may be comprised of gear  314  which is connected coaxially to and rotatable with the support shaft  310 , and lock pin  316  which is connected to the housing  12  and movable between lock position A and retreat position B in hole  317  in the housing  12 . When the lock pin  316  is located at the retreat position B, an operator can rotate the direction indicator dial  312 . When the lock pin  316  is moved to the lock position A and engaged with the gear  314 , it can secure the gear  314 , thereby securing the support shaft  310  and the stage  200  at that inclination. In an attempt to secure a stable operation by setting as a normal state the lock state of the stage  200 , the lock pin  316  may be forced to the lock position A by a spring member etc. In this case, the operator moves the lock pin  316  to the retreat position B before inclining the stage  200 . 
     If the stage  200  needs to be returned to the initial state (horizontal state) after the lock pin  316  is released from fixation, a spring member (not shown) may be provided as return device  306   a . One end of the spring member is fixed onto the bottom of the housing  12  and the other end is connected to the lower surface  202  of the stage  200 . 
     The scale  313  provided at the side of the housing  12  and the direction indicator dial  312  serve as the display  308  of the inclination apparatus  300   a . An operator may always obtain optimal operations by memorizing the inclined angle and using it for the next setting. 
     The barcode scanner  10 A shown in FIG. 6 may be used as a longitudinal type, as shown in FIG. 8, or as a lateral type as shown in FIG. 9, for example. An operator can obtain an inclined angle of the stage  200  optimal to him/her by simply adjusting the direction indicator dial  312 , irrespective of his/her height and experience. Therefore, the barcode scanner  10 A shown in FIGS. 6 and 7 may 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 to FIG. 6, although the rotational axis is made of the support shaft  310  which is an independent member, it is not necessary to constitute the rotational axis by an independent member when the stiffness of the stage  200  is utilized. For example, FIG. 10 schematically shows inclination apparatus  300   b  having one-dimensional inclination mechanism  302   b . In the inclination mechanism  302   a , one end of each of two support shafts  320  and  322  is fixed onto the bottom of the housing  12  and the other end thereof is rotatably attached to the lower surface  202  of the stage  200  by a hinge (not shown). A rotational axis corresponds to straight line  325  that connects joint  321  between the support shaft  320  and the stage  200  to joint  323  between the support shaft  322  and the stage  200 . Thus, the inclination mechanism  302   b  does not include a rotational axis as an independent member. The support shafts  320  and  322  do not have to stand perpendicular to the stage  200 . The stage  200  is inclinable around the straight line  325  by moving up and down operating shaft  326  that is connected to the stage  200  apart from the straight line  325 . 
     The support shaft  310  serving as a rotational axis is a member independent of the stage  200  in FIG.  6 . However, another (not shown) one-dimensional inclination mechanism may be adopted by processing part of the stage  200  into a pair of protrusions, and protruding these protrusions from the housing  12  to serve as a rotational axis. In this case, the one-dimensional inclination mechanism does not contain a rotational axis as an independent member, but the stage  200  has this function instead. 
     The moment application means is not limited to the direction indicator dial  312  that directly applies a moment to the support shaft  310 . For example, rather than the direction indicator dial  312 , if operating shaft  328  is coupled to the stage  200  parallel to the support shaft  310 , as in inclination apparatus  300   c  in FIG. 11, an operator may apply a moment to the stage  200  around the support shaft  310  by moving up and down in the drawing the operating shaft  328  which protrudes from the housing  12 . This case is similar to that of FIG. 6, in that the stage  200  is rotatable around the support shaft  310 , but it is different from FIG. 6 in that the support shaft  310  does not necessarily have the end  310   a  which protrudes from the housing  12 . The hole  16  in the housing  12  in which the operating shaft  328  moves would be formed as an arc, but could have a different shape as the shape of the operating shaft  328  changes. Needless to say, a position of the operating shaft  328  is not limited to that illustrated. 
     Although the operating shaft  328  is a member independent of the stage  200  in FIG. 11, it is possible to process part of the stage  200  into a protrusion, and protrude the protrusion from the hole  16  in the housing  12 , making this serve as the operating shaft  328 . Therefore, in this case, the one-dimensional inclination mechanism does not include the moment application means, but the stage  200  has this function instead. 
     If the stage  200  has the functions of the rotational axis and the moment application means, the stage  200  may additionally have functions of the securing mechanism, returning device, display, omitting inclination device  300  in FIG.  1 . Such barcode scanner  10 B is shown in FIG.  12 . FIG. 18 shows a case where the CPU  400  automatically controls such stage  200 . 
     FIG. 13 shows inclination apparatus  300   d  having another one-dimensional inclination mechanism  302   d . The inclination mechanism  302   d  includes plate support member  330  which is engaged with the lower surface  202  of the stage  200  at one end thereof, support shaft  331  as a rotational axis which penetrates through the stage  200 , and operating shaft  332  which is attached to the other end of the support member  330 . 
     The support shaft  331  is fixed onto the stage  200 , and supported rotatably by the housing  12 . The operating shaft  332  penetrates outside the housing  12  through arc  17  that is formed in the housing  12 . An operator may apply a moment to the support member  330  and the stage  200  by moving right and left in the drawing the operating shaft  332 . In this embodiment, the operating shaft  332  is spaced from the support shaft  331  of the stage  200  by a predetermined distance. 
     The support member  330  and the operating shaft  332  may be integrated into one member. The support member  330  is not limited to a plate-shaped member, but may be formed as an L-shaped rod so as to serve as the operating shaft  332 , omitting the operating shaft  332 . As stated, the stage  200  may have one or both of these functions. Processing part of the stage  200  may make the support shaft  331 . A position and shape of the support shaft  331  are not limited to those shown in FIG. 13, similar to the above embodiments. 
     The one-dimensional inclination mechanism may thus use, but is not limited to, many of the above structures. A description will now be given of the inclination mechanism  302  as a two-dimensional inclination mechanism. 
     The two-dimensional inclination mechanism is one which broadly inclines the stage  200  two-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 stage  200  via an operating point that is located outside the housing  12 . 
     A description will now be given of inclination apparatus  300   e  having two-dimensional inclination mechanism  302   e  which inclines the stage  200   a  in two axes, with reference to FIGS. 14 and 15. The inclination mechanism  302   e  includes support shafts  340  and  342 , stage  344 , different from the stage  200   a , which mounts the optical unit  100 , direction indicator dial  346  engaged with the support shaft  340 , direction indicator dial  348  engaged with the support shaft  342 , hinge  350  which engages the stage  200   a  with the stage  344 , spring member  352 , and cam  354 . 
     The support shaft  340  is coupled to the lower surface of the stage  344  by securing members  356  and  358 . As far as the support shaft  340  rotates together with the stage  344 , an arbitrary position and structure may be selected for the securing members  356  and  358 . For example, the securing members  356  and  358  may be comprised of the levers  319   a  and  319   b , as shown in FIG.  7 . 
     The stage  344  is coupled to the stage  200   a  by the hinge  350 . As the support shaft  340  rotates, the stage  344  that is integrated with it rotates together. The stage  200   a  also rotates with the stage  344  around the support shaft  340  since the hinge  350  connects the stage  200   a  with the stage  344  while prohibiting them from relatively rotating in a rotating direction of the support shaft  340 . Thereby, an operator may incline the stage  200   a  around the support shaft  340  by twisting the direction indicator dial  346 . 
     The stage  200   a  is rotatable relative to the stage  344  by the hinge  350  (in direction C in FIG.  15 ). The direction C is orthogonal to a rotatable direction of the support shaft  346 . The stage  200   a  is forced clockwise by the spring member  352 . 
     The support shaft  342  is connected to a top surface of the stage  344  by a securing member (not shown) similar to the securing members  356  and  358 . The cam  354  is coupled to and rotated with the support shaft  342 . The cam  354  is located between the hinge  350  and the spring member  352 , and contacts the lower surface  202  of the stage  200   a . As far as the cam  354  inclines the stage  200   a  when rotating with the support shaft  342 , by a different height which corresponds to the rotational angle, its shape is not limited to the illustrated one. The cam  354  is formed as a cylindrical shape and the support shaft  342  is shifted from the center of the cylinder in FIG. 15, but it is apparent that the cam  354  may have a shape similar to the direction indicator dial  348 . Thereby, the operator may incline the stage  200   a  around the hinge  350  by a height corresponding to the rotational angle by twisting the direction indicator dial  348  and rotating the support shaft  342  and the cam  350 . 
     Securing mechanism  304   e , returning device  306   e , and display  308   e  of the inclination apparatus  300   e  shown in FIGS. 14 and 15 may utilize those shown in FIG. 6, and a description thereof will be omitted. The spring member  352  serves as the returning device around the support shaft  342 . 
     Next follows a description of a two-dimensional inclination mechanism that broadly two-dimensionally inclines the stage  200 . First, a description will now be given of inclination apparatus  300   f  having two-dimensional inclination mechanism  302   f  of the present invention, with reference to FIG.  16 . FIG. 16 schematically shows the inclination mechanism  302   f , omitting the optical unit  100 . The inclination mechanism  302   f  includes support member  360  located beneath the centroid of the stage  200   b , spring members  362  which keep the stage  200   b  horizontal, and compression means  364  which apply forces onto the stage  200   b  from the top of the stage  200   b . In FIG. 16, the two-dimensional inclination mechanism  302   f  has four spring members  362  and four compression means  364 . 
     As far as the support member  360  properly serves as a fulcrum of inclination for the stage  200   b , it has an arbitrary shape. Referring to FIG. 16, a dent (not shown) is formed at the bottom of the stage  200   b  and the support member  360  has a conical shape having top  361  that is processed round so as to be partially engageable with the dent of the stage  200   b . Alternatively, the support member  360  may have a polygon pyramid or a sphere shape. 
     Each spring member  362  is connected to the bottom of the housing  12  at one end thereof, and the lower surface  202  of the stage  202   b  at the other end thereof. The spring member  362  is adjusted so that no spring force applies to the stage  200   b  at a horizontal state (initial state). The number and positions of springs are determined in accordance with the number and positions of compression means  364  so that the stage  202   b  becomes stable. Therefore, the spring member  362  may be provided below the compression means  364 . Alternatively, an elastic member other than the spring member  362  may be provided under the stage  200   b , for example, an elastic sponge that envelops the support member  360  under the stage  200   b.    
     The compression means  364  apply compression or tension forces to corners of the stage  200   b , and may adopt any structure. It is not necessary to provide four spots as shown in FIG.  16 . The compression means  364  is made, for example, by a link that is connected to the stage  200   b  through a hinge. Referring to FIG. 16, working one or more compression means  364  would apply a moment around the top  361  of the support member  360 . For example, when the compression means  364  is made of a link, any method known in the art can be applicable to secure the link and indicate the moving amount. The spring member  362  serves as the returning device. 
     A description will now be given of the CPU  400  shown in FIG.  1 . The CPU  400  is connected to the A/D converter part  164  of the optical unit  100 , the light control circuit  112 , the angle detecting device  146 , and the motor drive circuit  148 . The CPU  400  is also connected to the interface part  410 , the display part  420 , the speaker  422 , and an external power source (not shown). 
     The CPU  400  includes a ROM, a RAM, a timer, an I/O controller, etc. (not shown), and runs based on a program stored in the ROM or RAM. 
     The CPU  400  controls the light control circuit  112  by a method known in the art. The CPU  400  can control each element so that it may enter an energy-saving mode when the timer (not shown) detects that the barcode scanner  10  has not been used for a long time. 
     The CPU  400  sends an angle signal to the angle detecting device  146  and the motor drive circuit  148 , thereby controlling a rotational angle of the motor  144  (and the reflection surfaces  142  of the polygon mirror  140 ). 
     The CPU  400  receives a digital signal from the A/D converter part  164  of the light receiving part  160  and recognizes the barcode data. A barcode is recognized from data written down its top, middle, and end in a predetermined format. The CPU  400  judges 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 part  410 . Simultaneously, the CPU  400  may switch on and off the green light on the display  420 , and beeps from the speaker  422 , notifying an operator that the data has been validly recognized. 
     On the other hand, the CPU  400  judges 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 CPU  400  then switches on and off the red light on the display  420 , and optionally gives an alarm sound from the speaker  422 . Thus, the CPU  400  notifies the operator of the invalid reading and prompts him/her to do perform the reading over again. Incidentally, a description will be given later of control of the CPU  400  over the inclination apparatus  300  when the CPU  400  recognizes the part of barcode data. 
     Next follows a description of barcode scanner  10 C in which the CPU  400  automatically controls the inclination apparatus  300 , with reference to FIG.  17 . In this case, the CPU  400  controls the inclination apparatus  300  based on the program stored in the ROM or RAM (not shown). As shown in FIG. 18, the CPU  400  may control the stage  200  when the stage  200  serves as the inclination apparatus  300 , omitting the inclination apparatus  300 . However, this case would be easily understood from the description of control of the CPU  400  over the inclination apparatus  300 , and a description thereof will be omitted. 
     The CPU  400  in advance stores an optimal inclination angle for each operator in the ROM (not shown), and may control the inclination apparatus  300  based on it. 
     In this case, the CPU  400  obtains ID number data from the interface part  410  that the operator entered in the POS terminal, picks up inclined angle information corresponding to the ID from the ROM, and controls the inclination apparatus  300  based on that information. In this way, the operator may always obtain the optical unit  100  inclined at the optimal angle by simply entering his/her ID into the POS terminal. 
     When the CPU  400  does not store angle information for an operator, the CPU  400  conducts 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 CPU  400 , and a method in which the CPU  400  automatically detect the inclined angle and stores it. Moreover, even after the CPU  400  obtains 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 CPU  400  does 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 CPU  400 , 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 CPU  400  incline the stage  200  every predetermined angle (for example, five degrees) and enters the angle optimal to him/her into the CPU  400 . Optionally, the CPU  400  may 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 scanner  10 . 
     When the CPU  400  automatically detects an inclined angle, the CPU  400  may 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 CPU  400  would be able to detect the optimal inclined angle faster. 
     When the CPU  400  detects 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 CPU  400  automatically and sequentially inclines the stage  200  by every predetermined angle (for example, five degrees) and detects an angle when it acquires light reflected from a barcode. In this case, the CPU  400  may adopt a two-stage searching method. The CPU  400  initially 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 in FIG. 19, the barcode scanner  10 C has product detecting sensors  366  and indicator lamps  368  on the housing  12 . Needless to say, positions and arrangements of the product detecting sensors  366  and the indicator lamps  368  are not limited to those shown in FIG.  19 . 
     The product detecting sensors  366  are arranged in the longitudinal and lateral directions, covering the read window  14  at the top of the housing  12 , and their outputs are connected to the CPU  400 . The product detecting sensor  366  detects a shadow of merchandise and/or a barcode, and thereby detects its rough position. Any known sensor is applicable to the product detecting sensor  366 . The CPU  400  controls inclination by the inclination apparatus  300  based on a detection signal of the product detecting sensors  366 . 
     The indicator lamp  368  indicates a position of scanning pattern (or a reading area) emitted from the optical unit  100  on the inclined stage  200 , and informs an operator of it. The indicator lamp  368  turns on in accordance with an instruction from the CPU  400 . Thereby, an operator recognizes that a barcode should be approached to the reading area indicated by the indicator lamp  368 . 
     Where the CPU  400  detects 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 CPU  400  may detect the barcode moving path based on the detection signal of the product detecting sensors  366 , or it may detect the optimal inclined angle by making the inclination apparatus  300  incline the stage  200  randomly, and detecting the barcode moving path from the light reflected from the barcode at that time. 
     When the product detecting sensor  366  is used, there are provided a plurality of product detecting sensors  366  on the housing  12 . The CPU  400  may detect a barcode moving path by tracing the product detecting sensors  366  which respond to barcode&#39;s shadow which moves as the barcode moves. Referring to FIG. 20, a description will be given of an exemplary control method in which the CPU  400  detects the optimal inclined angle by detecting a barcode moving path, using the product detecting sensors  366 . 
     Initially, the CPU  400  judges whether or not the barcode scanner  10 C having the stage  200  at an inclined angle in an initial state (or operated state) could read a barcode (step  702 ). Such a judgement is based on whether the CPU  400  or 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 part  410  (step  704 ), and the CPU  400  maintains the inclined angle at that time. In the step  702 , if the barcode cannot be read, the CPU  400  checks the inclined angle of the stage  200  by the inclination apparatus  300  (step  706 ). 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 steps  702  and  706 . In that case, only if the number of reading errors reaches the predetermined times, the procedure is fed to the step  706 , otherwise is fed back to the step  702 , prompting the operator to repeat the reading operation. 
     Next, the CPU  400  obtains information relating to the barcode moving path from the product detecting sensors  366  (step  708 ), calculates the optimal inclined angle based on the it, and controls the inclination apparatus  300 , thereby modifying the current inclined angle to the optimal inclined angle (steps  710  and  712 ). In this case, it is conceivable that the barcode moving path by the operator was accidentally abnormal to the operator, so the CPU  400  may prompt the operator to move the barcode several times, and calculate the optimal inclined angle from the averaged moving path. 
     Control of the inclination apparatus  300  is conducted, for example, by controlling driving of the motor  370 , which will be described with reference to FIG.  22 . Thereafter, the barcode is read with the optimal inclined angle (step  714 ), but optionally the CPU  400  may inform and/or indicate the operator after the step  712  before the step  714  that the optimal inclined angle has been set. 
     If the reading operation succeeds, the CPU  400  outputs the result to the POS terminal (step  704 ), and if the reading operation fails, the CPU  400  prompts the operator to repeat the reading operation since the inclined angle has already been set to be optimal (step  716 ). 
     A barcode moving path is also detectable by utilizing light reflected from the barcode. A description will now be given of the CPU  400  in this case. The scanning pattern emitted from the optical unit  100  sequentially moves in the space as the motor  144  rotates. 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 CPU  400  may monitor this information momentarily, calculate a position of the scanning pattern which reads (even part of) data, and make the inclination of the stage  200  follow the calculation result. 
     For example, as shown in FIG. 4, a beam is emitted (as a scanning pattern) in three directions from one stationary mirror  152  as the polygon mirror  140  rotates and each reflection surface  142  changes an inclined angle. For instance, as shown in FIG. 21, a pair of V mirrors  154  generate V patterns  155   a  through  155   f , a pair of H mirrors  156  generate H patterns  157   a  through  157   f , and one Z mirror  158  generates Z patterns  159   a  through  159   c . The generation is repeated, by the rotation of the polygon mirror  140 , in the order of  155   a ,  157   a ,  159   a ,  155   d ,  157   d ,  155   b ,  157   b ,  159   b ,  155   e ,  157   e ,  155   c ,  157   c ,  159   c ,  155   f , and  157   f , and a barcode is recognized in this order. Therefore, if the barcode data enters in the order of  155   d ,  155   e , and  155   f , for example, the CPU  400  recognizes an area of the moving path is close to  155   d  through  155   f  and the moving direction is left to right in FIG.  21 . Based on this information, the CPU  400  may generate a control signal and control the inclination apparatus  300 . Since the CPU  400  obtains an entry order of the barcode data in step  708  (for example, the order of  155   d ,  155   e , and  155   f ) the control method in this case is similar to the procedure shown in FIG.  20 . 
     Next, a description will now be given of an operation of the CPU  400  when the inclination mechanism  302  comprises the one-dimensional inclination mechanism shown in FIG.  22 . The structure is similar to that in FIG. 7 except for the automatic inclination, and a duplicate description will be omitted. 
     The one-dimensional inclination mechanism shown in FIG. 21 includes motor  370 , gearbox  371 , motor drive circuit  372  which drives the motor  370 , support table  373  which supports the motor  370  and the gearbox  371 , potentiometer  374  as an angle detecting device which detects an inclined angle of the stage  200 , and support shaft  310  which is connected to and rotatable with the stage  200  and also connected directly or indirectly to and rotatable with the motor shaft (not shown) of the motor  370 . The motor drive circuit  372  and the potentiometer  374  are connected to and controlled by the CPU  400 . The CPU  400  obtains angular information of the stage  200  from the potentiometer  374 , and controls the motor drive circuit  372  based on this information. 
     The gearbox  371  serves to reduce a speed of the motor  370  and increase torque to be applied to the support shaft  310 . Thereby, even the small motor  370  can secure the torque enough to incline the stage  200 . 
     It is understood that when the stage  200  serves as the support shaft  310  the motor  370  is directly connected to the stage  200 . 
     In general, no securing device which secures the support shaft  310  (and the stage  200 ) (such as, the gear  314  and the lock pin  316  shown in FIG. 6) is required in the inclination apparatus  300   g  (inclination mechanism  302   g ) shown in FIG.  22 . This is because that the support shaft  310  is connected to the motor shaft (not shown) of the motor  370 , and the motor shaft and the support shaft  310  stops, when the motor drive circuit  372  stops 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 motor  370 , for example) stored in the CPU  400  or the motor drive circuit  372  in the inclination mechanism  302   g  shown in FIG.  22 . Therefore, no spring member is required to connect the lower surface  202  of the stage  200  to the bottom of the housing  12 . This is common to the following two-dimensional inclination mechanisms having similar structures. 
     No display is generally required in the inclination mechanism  302   g  in FIG.  22 . The primary purpose of the display is to notify the operator of the inclined angle for use with the next operation, but the CPU  400  memorizes 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 dial  312  is not required generally. However, if necessary, the angle detecting device  374  and/or an angle display connected to the CPU  400  may be independently provided. Such an angle display is useful for those 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 potentiometer  374  is connected to variable resistor  375  via lead line  376   a  and  376   b . The variable resistor  375  may apply resistance responsive to the rotational angle of the support shaft  310  to the potentiometer  375 . When the input voltage is made constant (for example, DC 5V), the resistance value of the variable resistor  375  can be detected by measuring the output voltage, whereby the rotational angle of the support shaft  310  can be detected. The motor drive circuit  372  serves as the moment application means. 
     Next, referring to FIG. 23, a description will be given of inclination apparatus  300   h  (inclination mechanism  302   h ) which is an automatic inclination version of the inclination apparatus  300   b  shown in FIG.  10 . The inclination mechanism  302   h  further includes, in addition to the elements of the inclination mechanism  302   b , angle detecting device  374  which detects an inclined angle of the stage  200 , moving device  376  which moves the operating shaft  326 , and drive device  378  which drives the moving device  376 . The moving device  376  and the drive device  378  may 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 device  376  and a motor drive circuit is used for the drive device  378 . In this case, the CPU  400  may incline the stage  200  by the predetermined angle by controlling a moving distance of the operating shaft  326  (which is expressed by the rotational angle of the motor shaft). 
     As shown in FIG. 11, where the operating shaft  328  is provided, the CPU  400  moves the operating shaft  328  up and down. The control method of the moving distance of the operating shaft  328  is similar to those for the moving device  376  and the drive device  378 . This is also similar to a case where the support member  330  and the operating shaft  332  are provided as shown in FIG.  13 . 
     Referring to FIG. 24, a description will now be given of inclination apparatus  300   i  (inclination mechanism  302   i ) which is an automatic inclination version of the inclination apparatus  300   e  shown in FIG.  14 . The inclination mechanism  302   i  includes, instead of direction indicators  346  and  348 , in the elements of the inclination mechanism  302   e , motors  380  and  381 , motor drive circuits  382  and  383  which drive the motors  380  and  381 , angle detecting device  384  which detects an inclined angle of the stage  200   a , and angle detecting device  385  which detects an inclined angle of the stage  344 . The support shaft  340  is connected directly or indirectly to and rotatable with the motor shaft (not shown) of the motor  380 , whereas the support shaft  342  is connected directly or indirectly to and rotatable with the motor shaft (not shown) of the motor  381 . The motor drive circuits  382  and  383  and the angle detecting devices  384  and  385  are connected to and controlled by the CPU  400 . The CPU  400  obtains angular information of the stages  200   a  and  344  from the angle detecting devices  384  and  385 , and controls the motor drive circuits  382  and  383  based on this information. 
     When the stage  200   a  and/or the stage  344  serve as the support shafts  340  and  342 , the motors  380  and  381  are connected to the stages  200   a  and  344 . 
     Each of the angle detecting devices  384  and  385  is similar to the angle detecting device  374 . A method for the CPU  400  to 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 stage  200   a  is not the support shaft  342  but the hinge  350  (see FIG. 15) in FIG.  24 . Therefore, the CPU  400  must, in advances, memorize the relationship between the rotational angle of the support shaft  342  and the inclined angle of the stage  200   a.    
     In automatically controlling the inclination apparatus  300   f  shown in FIG. 16, the CPU  400  may control an inclination angle of the stage  200   b  by controlling a moving distance of the compression means  364 . The moving distance of the compression means  364  is similarly controlled, as shown in FIG. 23, for example, by the angular detecting device  374  connected to the stage  200   b , the moving device  376  connected to the compression means  364 , and the drive device  378  connected to the moving device  376 . 
     As briefly shown in FIG. 25, which omits the optical unit  100 , inclination apparatus  300   j  (inclination mechanism  302   j ) may include four support members  390  which are hinged at the lower surface  202   c  of the stage  200   c . Four joints between these four support members  390  and the stage  200   c  correspond to corners of a square or a rectangle. The stage  200   c  may be inclined in an arbitrary direction by simultaneously moving up or down the adjacent two support members  390 . The CPU  400  similarly controls a moving distance of the compression means  364 , as shown in FIG. 23, for example, by using the angular detecting device  374  connected to the stage  200   c , the moving devices  376  connected to each support member  390 , and the drive device  378  connected to each moving device  376 . 
     Optionally, even when the CPU  400  automatically controls the inclination apparatus  300 , an operator may change the setting by manipulating a keyboard near the barcode scanner  10 . This is especially useful to avoid double reading when the barcode scanner  10   a  in FIG. 27 is 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 stage  200  (or the optical unit  100 ) does not collide with the inner wall of the housing  12 . 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 CPU  400 . The mechanical restriction is available as shown in FIG. 26, for example, where pin  315  provided on the gear  314  coaxial to the support shaft  310  in FIG. 6 is allowed to move in cutout  19  in the housing  12 . When the pin  315  rotates clockwise in FIG. 26, its movement is restricted by end  19   b  of the cutout  19 . When the pin  315  rotates counterclockwise in FIG. 26, its movement is restricted by end  19   b  of the cutout  19 . For example, in order to prevent the stage  200  in FIG. 6 from colliding with the housing  12  as a result of inclination, a buffer cushion may be provided inside the housing  12 . 
     A description will now be given of concrete actions of the barcode scanners  10 A through  10 D of the present invention. In the following discussion, the barcode scanner  10  generalizes the barcode scanners  10 A through  10 D and direction indicator dials and other elements are omitted in the drawings. 
     FIG. 27 shows the barcode scanner  10  installed on post  502   a . Keyboard  500   a  is provided next to the barcode scanner  10 . The barcode scanner  10  is connected to POS terminal  504 . The barcode scanner  10  shown in FIG. 27 is used as a longitudinal type. The height of the post  502   a  is adjustable depending upon operator&#39;s height. In operation, the operator picks up a merchandise out of a shopping basket that he/she has placed under the barcode scanner  10 , makes the barcode scanner  10  read the barcode, and returns the merchandise to the basket. However, if the basket is placed in the scanning-pattern emitting direction of the barcode scanner  10  and has merchandised with barcodes, there is a risk of double reading. As shown in FIG. 29, a method in which another basket is prepared and two baskets are placed at both ends of the barcode scanner  10  may 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 stage  200  by a mechanical operation or entry through keyboard  500   a  so 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 keyboard  500   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 unit  100  is 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 stage  200 . 
     FIG. 28 shows the barcode scanner  10  that is embedded into the cashier table and used as a lateral type. An operator stands at a front side in FIG.  28  and jumps a merchandise from left to right while making the intervening barcode scanner  10  read a barcode on the merchandise. This drawing shows a typical example of the barcode scanner  10  of the present invention. An operator may advantageously stand at the opposite side in FIG. 28 after the store-refurbishing etc., and jump a merchandise from right to left simply by changing an inclined angle of the stage  200 . 
     The barcode scanner  10  shown in FIG. 29 is also installed on post  502   b , but the post  502   b  is not adjustable in height. Keyboard  500   b  is located on the barcode scanner  10 , and the cashier table has a room for two baskets. This drawing also shows one of the most typical examples of the barcode scanner  10  of the present invention. 
     FIGS. 28 and 29 each have similar effects to those of FIG.  27 . 
     Referring to FIG. 30, a description will now be given of barcode scanner (two-faced scanner)  10 E 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 scanner  10 E shown in FIG. 30 has bending angle α as an obtuse angle, but the barcode scanner  10  of the present invention is applicable to one which has the bending angle α of an approximately right angle as shown in FIG.  31 . 
     As the two-faced scanner  10 E emits scanning patterns from two scanner parts  602  and  604 , and scans a barcode from multiple directions, thus providing a reading precision greater than the single-faced scanner. More specifically, the two-faced scanner  10 E 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 parts  602  and  604 . 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 scanner  10 E of the present invention has two scanner parts  602  and  604  which are bendable at joint  601 , guide indicator part  606  and switch  608  attached to the scanner part  602 , a pair of reading direction indicators  610  attached to the scanner  604 , and arrow mark  612  which indicates the bending angle α between the scanner parts  602  and  604 , and scale  614 . 
     In this way, the two-faced scanner  10 E is variable in bending angle α. Optionally, the bending angle α may be fixed to the predetermined value and made invariable. The scanner part  602  and/or the scanner part  604  may 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 parts  602  and  604  in accordance with the bending angle α, changing a position of the sweet spot S. The operator sets the bending angle α to an experimentally-determined optimal angle, confirming a value on the scale  614  indicated by the arrow mark  612 . 
     Next follows a description of a relationship between the scanning-pattern emitting direction of the scanner part  602  and the bending angle α. Referring to FIG. 32, the scanner part  602  has a linkage including movable arm  616  and fixed arm  619 . The movable arm  616  includes end  617  which is rotatably connected to the stage  200  which mounts the optical unit  100 , and fixed end  618  which is rotatable relative to the scanner part  602 . On the other hand, the fixed arm  619  is fixed onto the side of the stage  200 , and includes end  620  which is connected to the end  617  of the movable arm  616  and the stage  200 , and fixed end  621  which is rotatable relative to the scanner part  602 . The movable arm  616  moves in an arrow direction in FIG. 32 as the scanner part  602  moves relative to the scanner part  604  so that the bending angle α may increase. Thereby, the ends  617  and  620 , the stage  200 , and the optical unit  100  rotate counterclockwise around the fixed ends  618  and  621  as fulcrums. Therefore, as the bending angle α changes, the scanning-pattern emitting direction of the scanner part  602  changes accordingly. 
     For example, the two-faced scanner in FIG. 31 enables the scanner parts  602  and  604  to emit scanning patterns in directions perpendicular to the read windows  603  and  605 , respectively. Therefore, as shown in FIG. 33, the sweet spot S is formed near a position where focus distance (or optimal depth) L from the scanner part  604  is L 1 . On the other hand, in the two-faced scanner in FIG. 29, the scanner part  602  emits scanning pattern at acute angle with respect to the read window  603 . Therefore, as shown in FIG. 33, the sweet spot S is formed near a position where a focus distance L from the scanner part  604  is L 2 . Small L (e.g., L=L 1 ) is used to read small barcodes printed on a small merchandise, whereas large L (e.g., L=L 2 ) 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 L 1 , the merchandise collides with the scanner part  602  and 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 unit  100  in a path reverse to the scan light. 
     As shown in FIG. 35, the scanner parts  602  and  604  each generally correspond to one of the barcode units  10 A through  10 D. A variation which simplifies a structure is available; for instance, one CPU  400  may control both scanner parts  602  and  604 . Thus, even after the bending angle α is determined, and the scanning-pattern emitting direction of the scanner part  602  is determined by the linkage shown in FIG. 31, the stage  200  (and optical unit  100 ) can be changed in inclined angle, of course. 
     The guide indicator part  606  in FIG. 30 indicates a set value of the bending angle α, 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), shopping information, manipulation information, breakdown information of each part, and the like. The switch  608  may switch these information. 
     The guide indicator part  606  primarily 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 stage  200 , and the like. Alternatively, the guide indicator part  606  may be located at a position where a customer and the operator both can easily see it, for example, at the top of the scanner part  602 . Thus, the guide indicator part  606  can 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 part  606  is provided with the scanner part  602 , but may be formed as a different unit from the scanner part  602  or integrated with the keyboard unit. The guide indicator part  606  is 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 indicator  610  includes arrow marks. The arrow mark corresponding to a merchandise moving direction turns on. For example, as shown in FIG. 36, where a merchandise moves right to left, the right arrow mark which indicates the moving direction turns on, and the scanner part  604  emits 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.