BRIEF DESCRIPTION OF THE DRAWINGS
The above object and features of the present invention will become more apparent from the following description of some preferred embodiments with reference to the accompanying drawings, wherein:
FIG. 1 is a perspective view illustrating the whole constitution of a handy bar code reader for direct marking;
FIG. 2 is a perspective view illustrating the whole constitution of a general handy bar code reader;
FIG. 3 is a plan view illustrating examples of two-dimensional bar codes for direct marking;
FIG. 4 is a perspective view of when the handy bar code reader for direct marking of FIG. 1 is viewed from the side of the opening portion thereof;
FIG. 5 is a front view illustrating the internal structure of the handy bar code reader for direct marking of FIG. 1;
FIG. 6 is a perspective view of when the general handy bar code reader of FIG. 2 is viewed from the side of the opening portion thereof;
FIG. 7 is a front view illustrating the internal structure of the general handy bar code reader of FIG. 2;
FIG. 8 is a view schematically illustrating the constitution of a reading device according to an embodiment of the present invention;
FIG. 9 is a front view illustrating, on an enlarged scale, the constitution for detachably attaching a diffusion member of FIG. 8;
FIG. 10 is a front view illustrating, on an enlarged scale, the constitution for adjusting the mounting angle of the diffusion member of FIG. 8;
FIG. 11 is a diagram schematically illustrating a reading method according to an embodiment of the present invention; and
FIG. 12 is a diagram schematically illustrating the reading method according to another embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Here, prior to describing the reading device and the reading method according to the embodiment of the present invention, described below in detail with reference to the accompanying drawings (FIGS. 4 to 7) are the structure of a conventional handy bar code reader for direct making and of a general handy bar code reader on the side of the opening portion, and the internal structure thereof, that serve as a prerequisite for the present invention.
FIG. 4 is a perspective view of when the handy bar code reader for direct marking of FIG. 1 is viewed from the side of the opening portion thereof; FIG. 5 is a front view illustrating the internal structure of the handy bar code reader for direct marking of FIG. 1; FIG. 6 is a perspective view of when the general handy bar code reader of FIG. 2 is viewed from the side of the opening portion thereof; and FIG. 7 is a front view illustrating the internal structure of the general handy bar code reader of FIG. 2.
Illustrated here are the structures of the conventional handy bar code reader 100 for direct marking and of the general handy bar code reader 110 on the side of the opening portions and the internal structures thereof. Hereinafter, the same constituent elements as those described above will be denoted by the same reference numerals.
As in the handy bar code reader of FIG. 1 described above, the handy bar code reader 100 for direct marking shown in FIGS. 4 and 5 has a housing 1 incorporating therein an internal source of light 3, such as an LED which is a point sources of light, a grip portion 2, and a dedicated illumination portion 30 provided along the outer circumferential portion of the housing 1. An opening portion 31 made of a transparent resin plate or a glass plate is provided at the back of the dedicated illumination portion 30 but at an end portion of the housing 1.
Inside the housing 1, there are mounted a light-emitting portion projecting light IL emitted from the internal source of light 3 to a bar code BC of direct marking printed on the surface of a body MS, such as a metal body, a light-receiving lens 32 receiving light reflected by the bar code BC, and a light-receiving portion 33 reading signals from the bar code BC by receiving light focused by the light-receiving lens 32. The light-receiving portion 33 has a function of reading signals from the bar code BC by converting signals of light focused by the light-receiving lens 32 into electric signals, and is, desirably, constituted by a CCD or a CMOS (complementary metal oxide semiconductor) element. Here, light emitted from the internal source of light 3 or light reflected by the bar code BC propagates passing through the opening portion 31.
In the dedicated illumination portion 30 shown in FIGS. 4 and 5, further, a plurality of light-emitting elements (not shown), such as LEDs, are uniformly arranged along the outer cirumerential portion of the housing 1. Light DL emitted from the light-emitting elements is projected onto the bar code BC from the surrounding of the bar code BD of direct marking printed on the surface of the body MS. When the handy bar code reader 100 for direct marking is disposed close to the bar code BC of direct marking, the bar code BC of direct marking is illuminated by the dark visual field illumination, due to light DL emitted from the light-emitting elements. As will be obvious from the state of illuminating the bar code BC in FIG. 5, when the signals are read from the bar code BC of direct marking by using the handy bar code reader 100 for direct marking, the effect of illumination by the dark visual field illumination, due to light DL from the dedicated illumination portion 30, becomes greater than the effect of illumination by light IL from the internal source of light 3. This guarantees a stable and high reading ability without it being affected by the disturbance light reflected by the surface of the body MS.
In the handy bar code reader 100 for direct marking shown in FIGS. 4 and 5, a high reading ability is realized by increasing the effect of illumination by the dark visual field illumination of the dedicated illumination portion 30 imposing, however, a limitation on the distance to the body MS and on the reading direction for the body MS causing a great decrease in the operability and in the degree of freedom in reading the bar code BC of direct marking. Besides, to accomplish the illumination by the dark visual field illumination, a plurality of light-emitting elements, such as LEDs, must be uniformly arranged causing the structure of the dedicated illumination portion 30 to become complex to some extent and, hence, remarkably increasing the price of the reading device which comprises a handy bar code reader.
As in the handy bar code reader of FIG. 2 described above, further, the general handy bar code reader 110 shown in FIGS. 6 and 7 has a housing 1 incorporating therein an internal source of light 3, such as an LED, which is a point source of light, and a grip portion 2. An opening portion 31 made of a transparent resin plate or a glass plate is provided at an end portion of the housing 1.
Inside the housing 1, there are mounted a light-emitting portion projecting light IL emitted from the internal source of light 3 to a bar code BC of direct marking printed on the surface of a body MS, a light-receiving lens 32 receiving light reflected by the bar code BC, and a light-receiving portion 33 reading signals from the bar code BC by receiving light focused by the light-receiving lens 32, as in the handy bar code reader 100 for direct marking, of FIGS. 4 and 5, described above. Here, light IL emitted from the internal source of light 3 or light reflected by the bar code BC propagates passing through the opening portion 31.
In the general handy bar code reader 110 of FIGS. 6 and 7, however, no dedicated illumination portion is provided along the outer circumferential portion of the housing 1, unlike the handy bar code reader 100 for direct marking, of FIGS. 4 and 5, described above.
In other words, in the general handy bar code reader 110, only simple illumination is accomplished by light IL emitted from the internal source of light 3 which is the point source of light, which is subject to be easily affected by disturbance light reflected by the surface of the body MS. Therefore, its ability for reading the bar code BC of direct marking printed on the surface of the body MS tends to become lower than that of the handy bar code reader 100 for direct marking, of FIGS. 4 and 5, described above. This tendency becomes conspicuous particularly when the surface of the body MS is nearly a mirror surface, as is the surface of the metal body.
As will be obvious from the results of comparison in Table 1 described above, however, the general bar code handy reader shown in FIGS. 6 and 7 has many advantages over the handy bar code reader for direct marking of FIGS. 4 and 5, except for a poor ability for reading the bar codes. In the present invention, therefore, it is desired to provide a reading device which is capable of guaranteeing a high reading ability nearly equal to that of the handy bar code reader for direct marking, by improving the structure and arrangement of the general handy bar code reader of FIGS. 6 and 7.
Next, a reading device and a reading method according to preferred embodiments of the present invention contrived from the above point of view will be described with reference to the accompanying drawings (FIGS. 8 to 12).
FIG. 8 is a view schematically illustrating the constitution of the reading device according to an embodiment of the present invention. Here, the constitution of the reading device 8 according to the embodiment of the present invention is illustrated in a simplified manner.
As in the general handy bar code reader, of FIGS. 6 and 7, described above, the reading device 8 according to the embodiment of FIG. 8 has a housing 1 incorporating therein an internal source of light 3, such as an LED, and a grip portion 2 extending from the housing 1. An opening portion 31 made of a transparent resin plate or a glass plate is provided at an end portion of the housing 1.
Inside the housing 1, there are mounted a light-emitting portion projecting light emitted from the internal source of light 3 to a bar code BC of direct marking printed on the surface of a body MS, such as a metal body, a light-receiving lens 32 receiving light reflected by the bar code BC, and a light-receiving portion 33 reading signals from the bar code BC by receiving light focused by the light-receiving lens 32, as in the general handy bar code reader 100, of FIGS. 6 and 7, described above.
In the reading device 8 of the embodiment of FIG. 8, a diffusion member 4 for diffusing illumination light EB from an external source of light 9 (e.g., general light, such as ceiling lamps and the like) is attached to an end of the housing 1 via a mounting portion 5. The diffusion member 4 permits illumination light EB from the external source of light 9 to diffuse at a predetermined rate and to pass through at a predetermined rate, so as to uniformly fall as disturbance light SL on the bar code BC on the surface of the body MS. Desirably, the diffusion member 4 is made of a resin plate or a glass plate of which the surface has been delustered. Disturbance light SL that has fallen on the surface of the body MS through the diffusion member 4 is reflected by the bar code BC on the surface thereof and arrives at the light-receiving lens 32 and the light-receiving portion 33 through the opening portion 31.
In the general handy bar code reader as described above, only simple illumination is accomplished by light emitted from the internal source of light 3, which is subject to be easily affected by disturbance light SL reflected by the bar code BC on the surface of the body MS. Therefore, contrast of the bar code decreases and the ability for reading the bar code decreases, too.
In the reading device 8 according to the embodiment of FIG. 8, on the other hand, light falls uniformly on the light-receiving lens 32 and on the light-receiving portion 33 in the reading device, by positively utilizing the disturbance light SL reflected by the bar code BC on the surface of the body MS and by lowering the directivity of disturbance light SL through the diffusion member 4. This eliminates the effect of disturbance light SL reflected by the surface of the body MS, enhances the contrast of the bar bode, and greatly enhances the ability for reading the object to be read, such as bar code.
The reading device of FIG. 8 is used for reading the bar codes formed on the surface of the body but can further be used for reading marks and characters formed on the surface of the body.
FIG. 9 is a front view illustrating, on an enlarged scale, the constitution for detachably attaching the diffusion member of FIG. 8. Illustrated here on an enlarged scale and in a simplified manner is the constitution by which the diffusion member 4 is detachably attached to the housing 1 of the reading device 8 of FIG. 8.
In FIG. 9, a support shaft 51 is formed in a portion of the diffusion member 4. Further, a cam 52 is formed on the support shaft 51, the support shaft 51 and the cam 52 being allowed to rotate with respect to the housing 1. Further, a resilient member 50, such as a hinged spring, is provided on the housing 1.
In this constitution, the support shaft 51 is held by the resilient force of the resilient member 50 to thereby attach the diffusion member 4 to the housing 1 at a predetermined mounting angle. Further, the diffusion member 4 can be easily and detachably attached to the housing 1, depending upon the position of the cam 52 formed on the support shaft 51. When the cam 52 is, for example, at a position shown in FIG. 9, the diffusion member 4 is pulled in a direction of an arrow so as to be easily detached from the housing 1. When the diffusion member 4 that is once detached from the housing 1 is to be attached to the housing 1 again, the cam 52 is set at the above position and the diffusion member 4 is easily mounted on the housing 1.
When a plurality of kinds of bar codes BC (see FIG. 8) are formed on the surface of the body MS (see FIG. 8), in general, the contrasting state of the bar code differs depending upon the positions of the bar codes, and a situation may occur in which the diffusion member does not have to be attached for some bar codes.
To cope with the above situation, the constitution shown in FIG. 9 is employed in order to easily and detachably attach the diffusion member 4 to the housing 1, depending upon whether or not the diffusion member 4 is required for each of the bar codes.
FIG. 10 is a front view illustrating, on an enlarged scale, the constitution for adjusting the mounting angle of the diffusion member of FIG. 8. Illustrated here on an enlarged scale and in a simplified manner is the constitution by which the angle is adjustable for mounting the diffusion member 4 on the housing 1 in the reading device 8 of FIG. 8.
In FIG. 10, too, a support shaft 51 is formed in a portion of the diffusion member 4, as in the case of FIG. 9 described above. Further, a cam 52 is formed on the support shaft 51 and the support shaft 51 and the cam 52 can rotate with respect to the housing 1. Further, a resilient member 50 such as a hinged spring is provided on the housing 1. Moreover, a plurality of protuberances 6 are formed maintaining a predetermined gap on the resilient member 50 at positions in which the resilient member 50 comes in contact with the cam 52.
In this constitution, the support shaft 51 is held by the resilient force of the resilient member 50 to thereby bring the protuberances 6 on the resilient member 50 into engagement with the cam 52 at a position selected in advance, in order to attach the diffusion member 4 to the housing 1 in a state in which the mounting angle of the diffusion member 4 is suitably set with respect to the housing 1. Further, the angle of mounting the diffusion member 4 on the housing 1 is arbitrarily adjusted by varying the position in which the protuberances 6 of the resilient member 50 come into engagement with the cam 52. In this case, too, the diffusion member 4 can be easily and detachably attached to the housing 1, depending upon the position of the cam 52 formed on the support shaft 51, as in the case of FIG. 9 described above.
When a plurality of kinds of bar codes BC (see FIG. 8) are formed on the surface of the body MS (see FIG. 8), in general, the contrasting state of the bar code differs depending upon the angle of the housing 1 with respect to the individual bar codes or upon the positions (or angles) in which the illumination light from the external source of light falls on the surface of the body, and a situation may occur in which the angle for mounting the diffusion member 4 on the housing 1 must be varied.
To cope with the above situation, the constitution shown in FIG. 10 is employed in order to easily adjust the angle for mounting the diffusion member 4 on the housing 1, depending upon the angle of the housing 1 with respect to the bar code or upon the position in which the illumination light from the external source of light is falling on the surface of the body.
FIG. 11 is a diagram schematically illustrating a reading method according to an embodiment of the present invention. Illustrated here in a simplified manner is the reading method for reading bar codes BC of direct marking according to an embodiment of the present invention.
As in the case of FIGS. 6 and 7 described above, FIG. 11 uses the general handy bar code reader having a housing 1 which incorporates therein an internal source of light 3, such as an LED, and a grip portion 2 extending from the housing 1. An opening portion 31 made of a transparent resin plate or a glass plate is provided at an end portion of the housing 1.
Inside the housing 1, there are mounted a light-emitting portion projecting light emitted from the internal source of light 3 to a bar code BC of direct marking printed on the surface of a body MS, a light-receiving lens 32 receiving light reflected by the bar code BC, and a light-receiving portion 33 reading signals from the bar code BC by receiving light focused by the light-receiving lens 32, as in the case of FIGS. 6 and 7 described above.
In FIG. 11, further, a diffusion member 4a for diffusing illumination light EB from an external source of light 9 (e.g., general light, such as ceiling lamps and the like) is arranged surrounding (or surrounding only part of) the bar code BC of direct marking printed on the surface of the body MS. Here, illumination light EL that is diffused at a predetermined rate through the diffusion member 4a and has passed through the diffusion member 4a at a predetermined rate, is permitted to uniformly fall as disturbance light SL on the bar code BC on the surface of the body MS. Disturbance light SL that has fallen on the surface of the body MS through the diffusion member 4a is reflected by the bar code BC on the surface thereof and arrives at the light-receiving lens 32 and the light-receiving portion 33 through the opening portion 31.
According to the reading method of the embodiment of FIG. 11, light falls uniformly on the light-receiving lens 32 and on the light-receiving portion 33 in the general handy bar code reader by lowering the directivity of disturbance light SL, by arranging the diffusion member 4a surrounding the bar code BC on the surface of the body MS instead of attaching the diffusion member to the general handy bar code reader. This eliminates the effect of disturbance light reflected by the surface of the body, and greatly enhances the ability for reading the object to be read, such as bar code, as in the case of FIG. 8 described above.
According to the reading method of the embodiment of FIG. 11, directivity of disturbance light is lowered by simply arranging the diffusion member surrounding the body without varying the structure of the general handy bar code reader. Therefore, the ability for reading bar codes can be improved by a method simpler than that in the case of FIG. 8 described above.
FIG. 12 is a diagram schematically illustrating the reading method according to another embodiment of the present invention. Illustrated here in a simplified manner is the reading method for reading bar codes BC of direct marking according to another embodiment of the present invention.
As in the case of FIGS. 6 and 7 described above, FIG. 12 uses the general handy bar code reader having a housing 1 which incorporates therein an internal source of light 3, such as an LED, and a grip portion 2 extending from the housing 1. An opening portion 31 made of a transparent resin plate or a glass plate is provided at an end portion of the housing 1.
Inside the housing 1, there are mounted a light-emitting portion projecting light emitted from the internal source of light 3 to a bar code BC of direct marking printed on the surface of a body MS, a light-receiving lens 32 receiving light reflected by the bar code BC, and a light-receiving portion 33 reading signals from the bar code BC by receiving light focused by the light-receiving lens 32, as in the case of FIGS. 6 and 7 described above.
In FIG. 12, further, diffusion members 4b for diffusing illumination light from external sources of light 9 (e.g., general light, such as ceiling lamps and the like) are attached to the external sources of light themselves (or near to the external sources of light). Here, disturbance light SL that is diffused at a predetermined rate through the diffusion members 4b and has passed through the diffusion members 4b at a predetermined rate, is permitted to uniformly fall on the bar code BC on the surface of the body MS. Disturbance light SL that has fallen on the surface of the body MS is reflected by the bar code BC on the surface thereof and arrives at the light-receiving lens 32 and the light-receiving portion 33 through the opening portion 31.
According to the reading method of the embodiment of FIG. 12, light falls uniformly on the light-receiving lens 32 and on the light-receiving portion 33 in the general handy bar code reader, by building an illumination environment of low directivity by attaching the diffusion members 4b to the external sources of light themselves that form an environment for reading the bar codes instead of attaching the diffusion member to the general handy bar code reader. This eliminates the effect of disturbance light reflected by the surface of the body, and greatly enhances the ability for reading the object to be read, such as bar code, as in the case of FIGS. 8 and 11 described above.
According to the reading method of the embodiment of FIG. 12, directivity of disturbance light is lowered by simply attaching the diffusion members to the external sources of light forming the environment for reading bar codes without varying the structure of the general handy bar code reader. Therefore, the ability for reading the bar codes can be improved by a method simpler than that in the case of FIG. 8 described above.
With regard to the industrial applicability, the present invention is applied to a handy bar code reader of any type which is capable of realizing a high reading ability by excluding the effect of disturbance light, at the time of reading signals from an object to be read, by projecting light onto the object to be read, such as bar codes of direct marking formed on the surface of the body, such as a metal body, and by utilizing light reflected by the surface of the body.
Patent Application
20070278302
