TWI737095B - Optical information reading device - Google Patents

Abstract

[Problem] Provide a configuration that can switch to a state of polarization suitable for reading information codes without using multiple types of lighting units. [Solution] The first polarizing unit (41) arranged on the emission side of the illuminating unit (31) is configured to polarize the illuminating light in a predetermined polarization direction. Next, the second polarizing section (42) arranged on the light receiving side of the light receiving sensor (32) is configured as a switching polarization section, which can switch the reflected light from the information code (C) to be polarized in a direction different from the predetermined polarization direction. Either the state or the passing state in which polarized reflected light passes without polarization.

Description

Optical information reading device

The present invention relates to an optical information reading device, in particular to an optical information reading device that reads information contained in an information medium based on light reflected from an information medium such as an information code.

In recent years, an optical reading device that receives the reflected light from the information code in the light-receiving unit in a state where the illumination light is irradiated from the illuminating unit and reads the information code is often used. In the past, in this kind of optical reading device, in order to suppress the influence of the specular reflection on the display surface where the information code is displayed during the optical reading, a polarizing filter was used. That is, because the polarization of the light reflected by the specular surface is maintained at the time of reflection, the polarization direction of the polarizing filter on the exit side of the illuminating part is different from the polarization direction of the polarizing filter on the light receiving side of the light receiving part. The influence of specular reflection can be suppressed. On the other hand, because there are fine irregularities on the surface of the casting, etc., it will cause specular reflection as a whole. The information code formed on this irregular surface (for example, the information code formed by direct marking on the casting surface) produces Compared with the code part that does not cause specular reflection, a decodeable image is obtained. Therefore, when reading an information code formed on the above-mentioned concave and convex surface, the two polarizing filters configured as described above lose the contrast with the code portion, and there is a problem that a decodeable image cannot be obtained.

Regarding such a problem, as a technique for realizing the irradiation state of illuminating light suitable for reading of information codes, for example, an optical information reading device disclosed in Patent Document 1 below is known. In this optical information reading device, a window is arranged in the emission direction of the four light-emitting elements, and among the windows, the part where the light of the two light-emitting elements emits is provided with a polarizing filter, and the remaining two light-emitting elements The part where the light is emitted is not provided with a polarizing filter. In addition, in the window portion, in the portion where light enters the optical system of the imaging element, polarizing filters that are 90˚ different from the polarization direction of the polarizing filter are provided. With this configuration, when reading information codes that should suppress the influence of specular reflection, the two light-emitting elements provided with polarizing filters in the emission direction emit light, and when reading information codes formed on the uneven surface, the The two light-emitting elements that are not provided with the polarizing filter in the emitting direction emit light, thereby switching to an illumination state suitable for reading the information code. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2016-033787 A

[The problem to be solved by the invention]

In addition, in the structure of Patent Document 1 described above, it is necessary to prepare two types of illuminating parts: an illuminating part (light emitting element) provided with a polarizing filter and an illuminating part not provided with a polarizing filter. Therefore, when reading the information code, only one of the two types of illuminating units can be used. In order to ensure the amount of illuminating light (illuminance) necessary for reading the information code, the size of each illuminating unit is increased. In this case, there is a problem that the miniaturization of the optical system, that is, the miniaturization of the optical information reading device becomes difficult.

The present invention was completed to solve the above-mentioned problems, and its object is to provide a configuration that can switch to a polarized light state suitable for reading of information codes without using multiple types of illuminating units. [Means to Solve the Problem]

In order to achieve the above-mentioned purpose, the optical information reading device (10) described in claim 1 of the scope of the patent application includes: Illumination parts (31, 31a) that emit illuminating light to the information code (C); The first polarizing part (41, 41a) arranged on the exit side of the aforementioned illuminating part; The light receiving part (32) that receives the reflected light from the aforementioned information code; The second polarizing part (42) arranged on the light-receiving side of the aforementioned light-receiving part; A reading unit (21) that reads the information code in response to the light receiving result of the light receiving unit; in, The first polarizing part is configured in such a way that the illuminating light is polarized in a predetermined polarization direction; The second polarization unit is configured as a switching polarization unit, and can switch the state of the reflected light being polarized in a direction different from the predetermined polarization direction, And any one of the states in which the reflected light passes without polarization.

The optical information reading device (10) described in claim 4, comprising: Illumination parts (31, 31a) that emit illuminating light to the information code (C); The first polarizing part (41, 41a) arranged on the exit side of the aforementioned illuminating part; The light receiving part (32) that receives the reflected light from the aforementioned information code; The second polarizing part (42) arranged on the light-receiving side of the aforementioned light-receiving part; A reading unit (21) that reads the information code in response to the light receiving result of the light receiving unit; in, The first polarization unit is configured as a switching polarization unit, and can switch between the state of the illumination light being polarized in the first polarization direction and the state of the illumination light being polarized in the second polarization direction; The second polarization unit is configured to polarize the reflected light in the second polarization direction. In addition, the symbols in the above-mentioned parentheses indicate the correspondence relationship with the specific elements described in the embodiment described later. [Effects of the invention]

In the invention of claim 1, the first polarizing section arranged on the emission side of the illuminating section is configured such that the illuminating light is polarized in a predetermined polarization direction. Next, the second polarizing section arranged on the light receiving side of the light receiving section is configured as a switching polarization section, which can switch the state of polarization of the reflected light from the information code in a direction different from the predetermined polarization direction (hereinafter, also referred to as the polarization state) and Any of the states in which the reflected light passes without being polarized (hereinafter also referred to as the passing state).

In this way, the switching polarization unit is switched to the polarization state, because the polarization direction of the first polarization unit and the polarization direction of the second polarization unit become different directions, and when the reflected light from the information code is received, the illumination from the illuminating unit can be suppressed The effect of specular reflection caused by light. On the other hand, switching the polarizing section to the pass state, because the second polarizing section is not polarized, and when the information code formed on the uneven surface is read, the contrast with the code section will not be lost. Therefore, it is possible to switch to a state of polarized light suitable for reading the information code without using multiple types of illuminating units.

In the invention of claim 2, the first polarizer includes a diffuser that diffuses the illumination light, and a reflective polarizer that transmits light in the predetermined polarization direction among the light diffused by the diffuser and reflects the remainder toward the diffuser. Thereby, when the light reflected by the reflective polarizer is diffused again in the diffuser, the light that becomes a part of the predetermined polarization direction passes through the reflective polarizer, and the decrease in the amount of light caused by the polarization of the first polarizer can be suppressed. Ensure the amount of illumination light necessary for reading the information code.

In the invention of claim 3, the light-receiving unit includes a light-receiving sensor and an imaging lens for forming an image on the light-receiving surface of the light-receiving sensor. Next, the imaging lens is formed such that the maximum angle of the incident light formed by the light sensor is larger than the maximum angle of the emitted light formed by the light sensor, and the second polarizing part is arranged on the imaging lens and the light sensor. Between the devices.

In order to expand the imaging range, it is possible to use an imaging lens with a larger maximum angle of the incident light formed by the light-receiving sensor relative to the maximum angle of the emergent light formed by the light-receiving sensor, that is, a wide-angle lens. At this time, when the second polarizing part that functions as the switching polarizing part is arranged on the incident side of the imaging lens, the angle of light incident on the switching polarizing part becomes larger. Part of the specular reflection truncation effect will be weaker. Here, the second polarization section (switching polarization section) is arranged between the imaging lens (wide-angle lens) and the light sensor, compared with the case where the second polarization section (switching polarization section) is arranged on the incident side of the imaging lens Since the angle of the light incident to the switching polarization unit becomes smaller, even when a wide-angle lens for expanding the angle of view is used as an imaging lens, the specular reflection interception effect can be obtained over the entire imaging range.

In the invention of claim 4, the first polarizing section arranged on the emission side of the illuminating section is configured as a switching polarization section, and it is possible to switch between the state of polarization of the illumination light in the first polarization direction (hereinafter, also referred to as the first polarization state) and the illumination Any of the states in which the light is polarized in the second polarization direction (hereinafter also referred to as the second polarization state). Next, the second polarizing section arranged on the light receiving side of the light receiving section is configured such that the reflected light from the information code is polarized in the aforementioned second polarization direction.

By this, the switching polarization unit is switched to the first polarization state, because the polarization direction of the first polarization unit and the polarization direction of the second polarization unit become different directions, and the reflected light from the information code can be suppressed from the illumination unit. The effect of specular reflection caused by the illuminating light. On the other hand, the switching polarization part is switched to the second polarization state, because the polarization direction of the first polarization part and the polarization direction of the second polarization part become the same direction, and the polarized reflected light is not polarized in the second polarization part. When reading the information code formed on the concave and convex surface, the contrast with the code part will not be lost. Therefore, it is possible to switch to a state of polarized light suitable for reading the information code without using multiple types of illuminating units.

In the invention of claim 5, the switching polarization unit is composed of a liquid crystal and a polarizing plate. The liquid crystal has the function of switching the incident light into a state where the polarization direction is changed, for example, by 90˚, and the state where the polarization direction is not changed and the state where it is emitted is maintained as it is. Therefore, a combination of a liquid crystal and a polarizing plate constituted by removing one polarizing plate from a normal TN-type liquid crystal can realize a configuration capable of switching the polarization direction as a switching polarization unit at a low cost.

In the invention of claim 6, the liquid crystal includes a liquid crystal layer, and a pair of alignment films facing each other and having a rubbing direction different from each other by 90˚ through the liquid crystal layer. Formed in a way that one side is inclined.

Generally, a rectangular alignment film is formed, and the rubbing direction is formed parallel (vertical) to one side of the outer edge of the alignment film. It is known that when two such alignment films are used to receive polarized light, the The contrast at the end with a 45˚ slanting direction in the rubbing direction becomes lower. Therefore, when the liquid crystal with the above-mentioned alignment film is formed into a rectangular light-receiving portion with respect to the light-receiving surface, and the outer edge of the alignment film and the outer edge of the light-receiving surface are arranged in parallel, the rectangular light-receiving range is relative to the above The vicinity of the corner where the rubbing direction is inclined at about 45˚ will become a low contrast range, which may reduce the reading success rate.

Here, by arranging the alignment film so that the rubbing direction is inclined with respect to one side of the outer edge of the light-receiving surface of the light-receiving section, the range of low contrast can be changed to a direction different from the above-mentioned 45˚ left-right tilt direction. Therefore, it is easy to remove the range where the contrast becomes low from the rectangular light-receiving range, and it is possible to suppress the decrease in the reading success rate due to the above-mentioned decrease in the contrast.

In the invention of claim 7, the liquid crystal includes a liquid crystal layer including a spacer, and the liquid crystal layer has a content ratio of the spacer in a region that is a light-receiving range of the light-receiving portion than the gap in a region that is a range different from the light-receiving range. It is formed in a way that the content of the substance is still low. With this, when the distance between the liquid crystal on the optical axis and the light-receiving part is arranged such that the distance between the liquid crystal on the optical axis and the light-receiving portion becomes shorter, the spacers also become difficult to be imaged, and it is possible to suppress the deterioration of the quality of the captured image caused by the spacers in the liquid crystal layer. .

The invention of claim 8 includes a control unit that controls the switching of the switching polarization unit, and a detection unit that detects the end of the switching of the switching polarization unit. The light receiving unit starts after the switching of the switching polarization unit ends in response to the detection result of the detection unit. exposure. Thereby, since the exposure by the light receiving unit is surely started after the switching of the switching polarization unit is completed, the image during the switching of the switching polarization unit is not captured, and an image suitable for reading can be captured.

In the invention of claim 9, a memory unit that sequentially stores the captured images obtained from the light-receiving unit is provided, and the reading unit stores the captured image in the memory unit every time, and performs a function for interpreting and reading the information code of the captured image. Interpretation processing. Thereby, even during the switching of the switching polarization unit, the captured image can be decoded, and the processing efficiency can be improved compared with the case where the interpretation processing is started after the switching of the switching polarization unit is completed.

In the invention of claim 10, because the control unit switches the polarization unit according to the predetermined switching frequency, information codes that should suppress the influence of specular reflection or information codes formed on the uneven surface are mixed as reading targets. In, the information code can also be read smoothly.

In the invention of claim 11, in response to the interpretation result of the captured image obtained from the light receiving unit by the reading unit in one of the states (polarization state, first polarization state) switched by switching the polarizing unit, In the other switching state (passing state, second polarization state), the reading unit compares the result of interpretation of the captured image obtained from the light receiving unit, and the setting unit sets the switching frequency of the switching polarization unit, and the switching is based on the setting The frequency is switched by the control unit to switch the polarization unit. With this, even in the case where information codes or the like where the influence of specular reflection should be suppressed or information codes formed on a concave and convex surface are mixed as reading targets, it is possible to set the switching frequency according to the mixed condition. Therefore, the reading of the information code becomes easy to succeed, and the time for the reading process can be shortened.

In the invention of claim 12, in response to the interpretation result of the reading section obtained by changing the exposure conditions each time the exposure conditions are changed in one state (polarization state, first polarization state) switched by switching the polarization section, and The comparison result of the interpretation result of the reading section obtained by changing the exposure conditions each time in the other state of the switching state (passing state, second polarization state), the switching frequency and exposure conditions of the switching polarization section are set by the setting section . Thereby, the exposure condition setting switching frequency can also be added, the reading of the information code becomes easier to succeed, and the time for the reading process can be further shortened.

In the invention of claim 13, the illuminating unit includes a light source that emits illuminating light, and a light-collecting element that collects the illuminating light from the light source, and the first polarizing unit is arranged between the light source and the light-collecting element. Because the farther away from the light source, the more the illuminating light expands. Compared with the case where the first polarizing part is arranged on the exit side of the light collecting element, the area where the illuminating light enters the first polarizing part, that is, the illuminating light should be The area of the polarized light is reduced, and the size of the first polarizing part can be reduced.

[First Embodiment]

Hereinafter, the first embodiment for realizing the present invention will be described with reference to the drawings. The optical information reading device 10 shown in FIG. 1 is configured as a reading device that optically reads information contained in information media such as barcodes and QR codes (registered trademarks) or information media such as text information. Therefore, in the present disclosure, the information media such as information codes and text information are read by reflected light, which is also called optical information. The optical information reading device 10 has an outer profile formed by a case not shown in the figure, and thus various electronic components are housed in the case.

A control unit 21 for controlling the entire optical information reading device 10 is provided in the housing of the optical information reading device 10. The control unit 21 is composed mainly of elements of a microcomputer, and has elements such as a CPU 21A equipped with registers, a system bus 21B, an input/output (I/O) interface 21C, and the like. Together with the storage unit 22, it constitutes an information processing device IP. The control unit 21 decodes the data recorded in the information code by a predetermined interpretation method by reading processing using the captured image of the information code captured by the light-receiving sensor 32 of the optical system 30 described later. The memory unit 22 is configured by, for example, a semiconductor memory, and includes a RAM (random access memory) 22A and a ROM (read-only memory) 22B as an example. RAM22A is used as the main memory of CPU21A. In the ROM 22B, a predetermined program for executing reading processing and the like is stored in advance so as to be executable by the control unit 21 (CPU 21A). ROM22B also serves as a non-transitory computer-readable recording medium. In addition, the control unit 21 can be equivalent to an example of a "reading unit" that reads the information code in response to the result of light reception by the light sensor 32. In addition, the CPU is also called a microprocessor or processor.

In addition, the optical information reading device 10 includes an operation unit 23, a display unit 24, a light emitting unit 25, a communication interface 26, and the like. The operating unit 23 is provided with 1 or multiple keys provided on the outer surface of the case 3, and provides an operating signal to the control unit 21 in response to the user’s key-in operation. action. The display unit 24 is composed of liquid crystal or the like, and is controlled by the control unit 21 to display the result of reading the information code and the like on the screen. The light emitting unit 25 is, for example, an LED, and lights up in response to a signal from the control unit 21. The communication interface 26 is configured as an interface for performing data communication with external devices such as a host device, and performs communication processing in cooperation with the control unit 21.

In addition, the optical information reading device 10 is controlled by the control unit 21 (specifically, CPU21A), and is equipped with an optical system 30 for optically reading information codes and the like. The optical system 30 is divided into information codes as shown in FIG. A light projection optical system 30a that emits illumination light from an information medium, and a light receiving optical system 30b that receives reflected light from an information medium such as an information code. The projection optical system 30a includes an illuminating unit 31 that emits illuminating light to the information code, and a first polarizing unit 41 arranged on the emission side of the illuminating unit 31. The illuminating unit 31 has a light source such as an LED, an illuminating lens, etc., and is mounted on the circuit board 20a so as to irradiate illuminating light to an imaging range by the light receiving optical system 30b through a reading port (not shown) formed in the housing.

The first polarizing section 41 is a so-called polarizing plate, and the illumination light incident from the illuminating section 31 is irradiated to the imaging range through the reading port in a state of being constantly polarized in a predetermined polarization direction.

The light-receiving optical system 30b is composed of a light-receiving sensor 32, an imaging lens 33, a second polarizer 42 and the like. The light-receiving sensor 32 is composed of, for example, an area sensor in which light-receiving elements, which are solid-state imaging elements such as C-MOS and CCD, are two-dimensionally arranged, and has a light-receiving surface 32a as a rectangular light-receiving area. The light-receiving sensor 32 is mounted on the circuit board 20b so as to be able to receive (reflected light from an information medium such as an optical information code) incident on the light-receiving surface 32a through the imaging lens 33. In addition, the light-receiving sensor 32 can correspond to an example of the "light-receiving part".

The imaging lens 33 acts as an imaging optical system that collects the light incident into the housing through the reading port and can image the image on the light-receiving surface 32a of the light-receiving sensor 32, because it is fixed to the bracket 34 assembled on the circuit board 20b. , The positioning of the light-receiving sensor 32 and the like can be performed. In this embodiment, the illuminating light irradiated from the illuminating unit 31 through the first polarizing unit 41 is reflected by the information code C and the article with the information code C and the like R (refer to FIG. 1), and the reflected light passes through the second polarizing unit In the state of 42, the light is collected by the imaging lens 33, and the code image is formed on the light receiving surface 32 a of the light receiving sensor 32.

As shown in FIG. 2, the second polarizer 42 is arranged on the incident side of the imaging lens 33 (the light receiving side of the light receiving sensor 32 ). The second polarizing section 42 can switch between the polarization state of the reflected light from the information code passing through the reading port in a direction different from the polarization direction of the first polarization section 41 and the passing state of the reflected light passing through without polarization. . In addition, in the present embodiment, the second polarizing section 42 can correspond to an example of the "switching polarizing section".

Specifically, as shown in FIGS. 3 and 4, the second polarizing section 42 includes a rectangular liquid crystal 50 and a polarizing plate 60. The liquid crystal 50 is laminated with a liquid crystal layer 51 including a spacer 54, a pair of rectangular alignment films 52a, 52b facing each other through the liquid crystal layer 51 sealed by a sealing material 55, and glass substrates 53a, 53b for protecting from both sides .

The liquid crystal layer 51 has a content ratio of the spacer 54 in the central area (refer to the symbol S in FIG. 3) of the imaging range (light-receiving range) of the light-receiving sensor 32 than in the peripheral area which is a range different from the imaging range. It is formed so that the content rate of the spacer 54 is still low. For example, by shielding the above-mentioned central area when the spacers 54 are scattered, it is possible to form an area where the content rate of the spacers 54 becomes low. In addition, the pair of alignment films 52a and 52b are arranged such that the rubbing direction is 90° different.

The liquid crystal 50 controls the voltage application state by the control unit 21 (CPU 21A). Therefore, the liquid crystal 50 responds to the control performed by the control unit 21 to switch between the state where the incident light is emitted with the polarization direction changed by 90˚ due to no voltage being applied, and the state where the incident light is emitted without changing the polarization direction due to the applied voltage to maintain the original state. The way the state works.

The polarizing plate 60 is configured to emit incident light incident through the liquid crystal 50 to the imaging lens 33 in a state where the light is constantly polarized in a different direction with respect to the polarization direction of the first polarizer 41.

That is, the second polarizing section 42 is configured by a combination of the liquid crystal 50 and the polarizing plate 60 so that one polarizing plate on the incident side is removed from the TN mode liquid crystal.

In the second polarizing section 42 configured in this manner, when a voltage is applied to the liquid crystal 50, the reflected light from the information code or the like enters the polarizing plate 60 without changing its polarization direction from the liquid crystal 50. At this time, because the polarization direction of the reflected light emitted from the liquid crystal 50 and the polarization direction of the polarizing plate 60 are 90˚ different, the reflected light becomes a polarization state where the light is polarized in a direction different from the polarization direction of the first polarizer 41 . On the other hand, when no voltage is applied to the liquid crystal 50, the reflected light from the information code or the like is incident on the polarizing plate 60 from the liquid crystal 50 in such a manner that the polarization direction thereof is changed by 90°. At this time, since the polarization direction of the reflected light emitted from the liquid crystal 50 and the polarization direction of the polarizing plate 60 become the same direction, the polarized reflected light passes through without being polarized. That is, the second polarizing section 42 is configured as a switching polarization section, and in response to the voltage control of the liquid crystal 50 by the control section 21, it is possible to switch the polarization state in which the reflected light is polarized in a direction different from the polarization direction of the first polarizing section 41, And any one of the passing states in which the reflected light passes through without being polarized. Therefore, the control unit 21 functions to control the switching of the polarization state and the passing state of the second polarization unit 42.

In the optical information reading device 10 configured in this way, in the reading process performed by the control unit 21 (CPU21A) when reading the information code, when reading the information code that should suppress the influence of specular reflection, the second The polarizing section 42 is switched to the polarized state, and the second polarizing section 42 can be switched to the passing state when reading the information code or the like formed on the uneven surface.

As described above, in the optical information reading device 10 of this embodiment, the first polarizing section 41 arranged on the emission side of the illuminating section 31 is configured such that the illuminating light is polarized in a predetermined polarization direction. Next, the second polarizing section 42 arranged on the light receiving side of the light receiving sensor 32 is configured as a switching polarization section, which can switch the state of the reflected light from the information code being polarized in a direction different from the predetermined polarization direction and the polarized reflected light Any of the passing states that pass without polarization.

Thereby, the second polarizing part 42 is switched to the polarized state, because the polarization direction of the first polarizing part 41 and the polarization direction of the second polarizing part 42 become different directions, and the reflected light from the information code can be suppressed from The influence of the specular reflection caused by the illumination light of the illumination unit 31. On the other hand, the second polarizing section 42 is switched to the passing state, because the reflected light that has been polarized is not polarized by the second polarizing section 42. When the information code formed on the uneven surface is read, the contrast with the code section is not good. Will be lost. Therefore, it is possible to switch to a state of polarized light suitable for reading the information code without using multiple types of illuminating units.

Next, by configuring the second polarizing section 42 as a switching polarizing section, the following effects can be achieved. When the first polarizing section 41 arranged on the exit side of the illuminating section 31 is configured as a switching polarization section, the number of the first polarizing sections 41 increases as the number of illuminating sections 31 increases, and there is a possibility that the number of component points increases. Therefore, because the polarization state and the passing state can be switched in the second polarizing section 42 arranged on the light receiving side of the light receiving sensor 32, even when the number of illuminating sections 31 is increased for the purpose of ensuring the amount of light, etc., It is not necessary to increase the number of second polarizers 42 and it is possible to suppress an increase in the number of component points.

In particular, the second polarizing part 42 is configured by the liquid crystal 50 and the polarizing plate 60 as a switching polarizing part. Since the liquid crystal 50 has the function of switching the incident light to a state where the polarization direction is changed by 90˚ to emit, and the polarization direction does not change, the function of maintaining the original state of emission, removes one piece of polarized light from the normal TN type liquid crystal The combination of the liquid crystal 50 and the polarizing plate 60 configured in the form of a plate can realize a configuration in which the polarization state and the passing state can be switched at a low cost.

Furthermore, the liquid crystal layer 51 including the spacer 54 has a higher content ratio of the spacer 54 in the central area S of the imaging range of the light-receiving sensor 32 than the spacer 54 in the peripheral area which is a range different from the imaging range. 54 is formed in a way that the content rate is still low. Accordingly, when the distance between the liquid crystal 50 on the optical axis and the light-receiving sensor 32 becomes shorter, the spacer 54 also becomes difficult to be imaged, and it is possible to suppress the occurrence of the spacer 54 in the liquid crystal layer 51. The quality of the camera image is reduced.

[Second Embodiment] Hereinafter, the optical information reading device of the second embodiment will be described with reference to the drawings. In addition, components having the same or similar components as those of the first embodiment use the same reference numerals, and their descriptions are omitted or simplified. This explanation method is the same in various embodiments described later. In the second embodiment, the first polarizing section 41 is mainly configured as a switching polarization section, and the second polarizing section 42 is configured as a polarizing plate, which is different from the above-mentioned first embodiment.

Specifically, the first polarizing section 41 arranged on the exit side of the illuminating section 31 is configured as a switching polarization section, and can switch the state of the illumination light polarized in the first polarization direction and the state of the illumination light in the second polarization direction (for example, relative to the second polarization direction). 1 Polarization direction is 90˚ different directions) Any of the second polarization states of polarized light. Therefore, in this embodiment, the first polarizing section 41 includes the liquid crystal 50 and the polarizing plate 60, and the polarizing plate 60 is on the incident side. Next, the second polarizing section 42 arranged on the light receiving side of the light receiving sensor 32 serves as a polarizing plate 60 with a polarization direction different from that of 90˚, and the reflected light from the information code is constantly polarized in the second polarization direction. Mode composition.

Even so, by switching the first polarization section 41 to the first polarization state, since the polarization direction of the first polarization section 41 and the polarization direction of the second polarization section 42 become different, when the reflected light from the information code is received Therefore, it is possible to suppress the influence of the specular reflection caused by the illumination light from the illumination unit 31. On the other hand, the first polarization section 41 is switched to the second polarization state, because the polarization direction of the first polarization section 41 and the polarization direction of the second polarization section 42 become the same direction, and the polarized reflected light is in the second polarization section. 42 will not be polarized, and when reading the information code formed on the concave and convex surface, the contrast with the code part will not be lost. Therefore, it is possible to switch to a state of polarized light suitable for reading the information code without using multiple types of illuminating units.

Next, by configuring the first polarizing section 41 as a switching polarizing section, the following effects can be achieved. When the second polarizing section 42 arranged on the light receiving side of the light receiving sensor 32 is configured as a switching polarization section, it depends on the performance of the imaging system including the light receiving sensor 32 (for example, the number of sensor pixels and the analysis of the imaging lens). Since the distance between the second polarizer 42 and the light sensor 32 on the optical axis is close to each other, it may be caused by defects of the second polarizer 42 (for example, adhesion of dust, glass damage, defects, etc.). , The situation where the quality of the camera image is degraded. Therefore, by configuring the first polarizing section 41 arranged on the exit side of the illuminating section 31 as a switching polarizing section capable of switching between the first polarization state and the second polarization state, the first polarization section 41 on the optical axis can be pulled apart. The distance from the light-receiving sensor 32 can suppress the deterioration of the quality of the picked-up image caused by the defect of the first polarizing portion 41 or the like.

[Third Embodiment] Hereinafter, the optical information reading device of the third embodiment will be described with reference to FIGS. 5 to 8. The third embodiment is mainly different from the first embodiment described above in that the rubbing direction of the pair of alignment films is different from the rubbing direction of the pair of alignment films in the first embodiment. Therefore, components that are substantially the same as those of the first embodiment are given the same reference numerals, and the description thereof is omitted.

In this embodiment, in the second polarizing section 42, instead of the above-mentioned liquid crystal 50, a liquid crystal 50a is used. As shown in FIG. 5, the pair of alignment films 52c and 52d used in the liquid crystal 50a are formed such that the rubbing direction is inclined with respect to one side of the outer edges of the alignment films 52c and 52d. In addition, in FIGS. 5 and 6, for the convenience of description, some of the liquid crystal molecules are exaggeratedly illustrated, and except for the alignment film, polarizing plate, and light-receiving sensor that are simply illustrated, the illustration of some components is omitted.

Therefore, the effect achieved by inclining the rubbing direction with respect to one side of the outer edge of the alignment film will be described with reference to the drawings. Generally, a rectangular alignment film is formed such that the rubbing direction is parallel (vertical) to one side of the outer edge of the alignment film as shown in the alignment films 52a and 52b shown in FIG. 6. It is known that when two such alignment films 52a and 52b are used to receive polarized light, the contrast at the end portions inclined at about 45° with respect to the rubbing direction becomes low.

Therefore, the liquid crystal 50 having the alignment films 52a, 52b in the alignment direction shown in FIG. 6 is formed into a rectangular light receiving sensor 32 with respect to the light receiving surface 32a. When the outer edges are arranged in parallel, the light-receiving sensor 32 becomes the light-receiving range shown in FIG. 8. That is, in the rectangular light receiving range (refer to the symbol L in FIG. 8), the vicinity of the corner that is inclined to about 45˚ with respect to the above-mentioned rubbing direction becomes a low contrast range (refer to the symbol N in FIG. 8) , There is a possibility that the reading success rate will decrease.

Here, in this embodiment, as shown in a pair of alignment films 52c and 52d shown in FIG. 5, the rubbing direction is formed to be inclined with respect to one side of the outer edges of the alignment films 52c and 52d. In this embodiment, the rubbing direction of the alignment films 52c and 52d is formed to be inclined at about 45° with respect to one side of the outer edge. That is, the plane along the alignment films 52c, 52d is parallel to the light-receiving surface 32a, and the liquid crystal 50a is arranged such that the outer edges of the alignment films 52c, 52d and the light-receiving surface 32a are parallel to the light-receiving sensor 32. The alignment films 52c and 52d are arranged such that the rubbing direction is inclined with respect to one side of the outer edge of the light receiving surface 32a of the light receiving sensor 32.

Thereby, the range N in which the contrast becomes low can be changed to a direction different from the above-mentioned 45˚ left and right inclined direction. Therefore, it is easy to remove the range N in which the contrast becomes low from the rectangular light receiving range L, and it is possible to suppress the decrease in the reading success rate due to the above-mentioned decrease in the contrast.

For example, as described above, after the rubbing direction is formed to be inclined at about 45° with respect to one side of the outer edge, the light receiving range L shown in FIG. 7 can be removed from the light receiving range L where the contrast is reduced. In addition, the alignment films 52c and 52d are not limited to being formed in such a manner that the rubbing direction is inclined to the side of the outer edge by 45˚, if the rubbing direction is inclined with respect to the side of the outer edge of the light receiving surface 32a of the light receiving sensor 32 The configuration of the arrangement, for example, can be formed in an inclined manner of about 30˚, or may be formed in an inclined manner of about 60˚.

In addition, the characteristic configuration of the present embodiment in which the rubbing direction of the pair of alignment films is formed to be inclined with respect to one side of the outer edge of the alignment film can also be applied to other embodiments and the like.

[Fourth Embodiment] Hereinafter, the optical information reading device of the fourth embodiment will be described with reference to the drawings. The fourth embodiment is different from the above-mentioned first embodiment in that information codes are mainly captured while controlling the switching between the polarization state and the passing state (switching state). Therefore, components that are substantially the same as those of the first embodiment are given the same reference numerals, and the description thereof is omitted.

In this embodiment, on the premise that the information codes etc. which should suppress the influence of specular reflection or the information codes formed on the concave and convex surface are mixed as the reading targets, the reading process performed by the control unit 21 when the information codes are optically read, The switching in the second polarizing unit 42 is performed in accordance with a predetermined switching frequency.

Hereinafter, in this embodiment, the reading process performed by the control unit 21 will be described in detail using the flowchart shown in FIG. 9. After the reading process is started by the control section 21 in response to a predetermined operation of the operation section 23, the initial setting process shown in step S101 in FIG. 9 is performed. In this process, the switching frequency and exposure conditions of the second polarizer 42 are set based on a predetermined reading condition table. However, in this embodiment, the switching frequency is set in accordance with the ratio of the number of times the captured image is acquired in the polarization state to the number of times the captured image is acquired in the passing state. In the following description, a voltage is applied to the liquid crystal 50 at the start of the reading process, and the second polarizer 42 becomes a polarized state. After repeating the polarized state to obtain two captured images, then one captured image is obtained in the passing state. The method of image processing is set in the case where the switching frequency is determined in advance. In addition, regarding the exposure conditions of the light-receiving sensor 32 and the like, the polarization state and the passing state are different, and are set in advance under appropriate conditions respectively.

After the switching frequency is set as described above, in response to the instruction of the control unit 21, the exposure of the light-receiving sensor 32 is started under the preset exposure conditions (S103). Next, after the exposure is completed (S105: Yes), in the determination process of step S107, it is determined whether or not to implement switching in the second polarizing section 42. However, when it is determined that the switching is not necessary due to the switching frequency, it is determined as No in the above step S107, and the acquisition of the captured image from the light-receiving sensor 32 after the exposure is started for the storage unit 22 (S109). Then, after the acquisition is completed (S111: Yes), exposure starts again (S103).

Next, after the exposure is finished (S105: Yes), when the switching of the second polarizer 42 is performed in accordance with the above-mentioned switching frequency, it is determined as Yes in step S107. At this time, the acquisition of the captured image from the light-receiving sensor 32 whose exposure has ended is started (S113), and the switching in the second polarizing section 42 is started (S115). When switching from the polarization state to the passing state is started, the voltage application to the liquid crystal 50 is stopped.

Next, in the determination process of step S117, it is determined whether the acquisition of the captured image to the storage unit 22 and the switching of the second polarizing section 42 have ended at the same time, the acquisition of the captured image to the memory section 22 and the switching of the second polarizing section 42 are determined. The judgment of No is repeated until both ends. In addition, in step S117 described above, the control unit 21 that detects the completion of the switching of the second polarizing unit 42 can be equivalent to an example of the "detection unit".

Then, after the acquisition of the captured image to the memory unit 22 and the switching of the second polarizing unit 42 are completed (S117: Yes), the exposure conditions are changed to the exposure conditions suitable for the switched state (S119), and exposure is restarted (S103). When switching from the polarization state to the pass state, change to the exposure conditions suitable for the pass state, and start exposure again.

Next, as described above, during the process of repeatedly performing the acquisition of the captured image to the memory section 22 and the switching of the second polarizing section 42 due to the end of exposure, the image buffer prepared in the memory section 22 will depend on each time the acquisition is completed. The captured image is sequentially memorized, and the control unit 21 performs interpretation processing for decoding (deciphering) the captured image to decode (decipher) the information code.

Here, as another case of setting the switching frequency, the timing chart shown in Fig. 10 will be used to specifically describe when the switching frequency is set to repeat the process of acquiring one captured image in the polarized light state and then acquiring one captured image in the passing state. The flow of the read processing.

As shown in FIG. 10, in a state where the polarization state is initially set and the exposure conditions (exposure conditions A) suitable for the polarization state are set, exposure by the light sensor 32 is started. Next, after the exposure is completed (refer to t11 in FIG. 10), the acquisition of the captured image from the light-receiving sensor 32 after the exposure is completed, and the switching from the polarization state to the passing state is started. Next, after the captured image is stored in the image buffer 1 prepared in the storage unit 22 (refer to t12 in FIG. 10) due to the completion of the acquisition, the interpretation process is started on the stored captured image without waiting for the end of the switching. In the present embodiment, the captured image is stored in the image buffer until the interpretation process is completed, and is erased when the interpretation process is completed.

Next, after the switching from the polarization state to the passing state is completed (refer to t13 in FIG. 10), the exposure condition (exposure condition B) suitable for the passing state of the switching is set, and the photodetector 32 is started. exposure. Next, after the exposure is completed (refer to t14 in FIG. 10), the acquisition of the captured image from the light-receiving sensor 32 after the exposure is completed is started, and the switching from the passing state to the polarization state is started. In addition, when the interpretation process at the start of exposure has not ended, as shown in FIG. Next, when the switching is completed but the acquisition is not completed (refer to t15 in FIG. 10), exposure is not started, and when the acquisition is completed after the switching is completed (refer to t16 in FIG. 10), the interpretation process of the memorized captured image is started, and exposure is started .

Next, when the acquisition of the captured image after the exposure ends but the previously started interpretation process has not ended (refer to t17 in FIG. 10), the interpretation process of the captured image that has been acquired is in a standby state until the previous interpretation process ends. Next, the completed captured images are acquired before the previous interpretation process is completed, and are sequentially stored in the image buffer separately prepared in the storage unit 22.

As described above, in the optical information reading device 10 of this embodiment, the control unit 21 controls the switching of the second polarizing unit 42 and functions as a detection unit that detects the end of the switching of the second polarizing unit 42 in the reading process. . The light-receiving sensor 32 is controlled by the control unit 21 in response to the detection result of the detection unit, and starts exposure after the switching of the second polarizing unit 42 is completed (S117: Yes).

With this, since the exposure by the light sensor 32 is surely started after the switching of the second polarizing section 42 is completed, the image during the switching of the second polarizing section 42 will not be captured, and an image suitable for reading can be captured. .

In particular, in this embodiment, a memory unit 22 that sequentially stores captured images acquired from the light-receiving sensor 32 as an image buffer is provided. The image interprets the interpretation of the information code. Thereby, even during the switching of the second polarizing unit 42, it is possible to perform the interpretation processing on the captured image that has been captured. Compared with the case where the interpretation processing is started after the switching of the second polarizing unit 42 is completed, the interpretation processing can be performed. Improve processing efficiency.

Furthermore, in the present embodiment, since the control unit 21 performs switching in the second polarizing unit 42 in accordance with the predetermined switching frequency, the information code or the like that should suppress the influence of specular reflection or the information code formed on the uneven surface is used as a reading In the case of mixed objects, the information code can be read smoothly.

In addition, in the reading process performed in the above-mentioned second embodiment in which the first polarizing section 41 functions as a switching polarizing section, the switching in the first polarizing section 41 may be performed in accordance with a predetermined switching frequency or the like.

[Fifth Embodiment] Hereinafter, the optical information reading device of the fifth embodiment will be described with reference to the drawings. The fifth embodiment differs from the above-mentioned fourth embodiment mainly in that the switching frequency of the switching polarization unit is set by the interpretation result of the interpretation processing. Therefore, components that are substantially the same as those in the fourth embodiment are given the same reference numerals, and the description thereof is omitted.

In the present embodiment, in the setting processing such as the switching frequency performed by the control unit 21, in response to the interpretation result of the interpretation processing of the captured image obtained from the light-receiving sensor 32 in the polarization state switched by the second polarization unit 42, The comparison result with the interpretation result of the interpretation process of the captured image acquired from the light-receiving sensor 32 in the passing state sets the switching frequency and exposure conditions in the second polarizer 42.

Specifically, for example, when reading additional information codes for a plurality of items in sequence, one item is extracted from the plurality of items, and the information code attached to the extracted item is changed in the polarization state and the passing state. The conditions and so on are read and tested. Next, in accordance with the reading result of the reading test, the switching frequency and exposure conditions suitable for reading the information code attached to the plural articles are set. In addition, the control unit 21 that performs setting processing such as the switching frequency can correspond to an example of the "setting unit" that sets the switching frequency of the switching polarization unit.

Hereinafter, in the present embodiment, with reference to the flowchart shown in FIG. 11, the setting processing of the switching frequency and the like performed by the control unit 21 will be described in detail. After the control unit 21 starts processing such as switching frequency in response to a predetermined operation of the operation unit 23, the provisional setting processing shown in step S201 in FIG. 11 is performed. In this process, the switching state (polarization state, passing state) and exposure conditions of the second polarizing section 42 of the complex pattern prepared in advance for the reading test are read, and the initial switching state and exposure conditions are temporarily set.

Next, after the initial settings of the switching state for the reading test and the exposure conditions are completed, a reading test that repeats the process of reading the information code a predetermined number of times is performed (S203). Next, when the combination of all the switching states and exposure conditions read out as a reading test is not performed (S205: No), change the setting of the next switching state and exposure conditions (S207), and perform the above-mentioned reading test again (S203) .

Next, when a combination of all switching states and exposure conditions read out as a reading test is performed (S205: Yes), the switching frequency and exposure conditions are determined in accordance with the comparison result of the reading test (S209).

Specifically, for example, as illustrated in FIG. 12(A), when the reading success rate of the results of the reading test performed under the four types of exposure conditions A to D is obtained for each of the polarization state and the passing state, select the reading Take the exposure condition with the highest success rate, and set the switching frequency in accordance with the ratio of the reading success rate of the selected exposure condition. In the example of Fig. 12(A), because the reading success rate of exposure condition A is 90% in the polarized state is the highest, and the reading success rate of exposure condition B is 90% in the passing state, as shown in Fig. 12( B) As an example, the switching frequency is set at the ratio of the polarization state, the exposure condition A becomes 1, the pass state, and the exposure condition B becomes 1. In addition, when the highest reading success rate is less than the predetermined threshold (for example, 60%), the switching state is not selected, and only another switching state in which the reading success rate is equal to or higher than the predetermined threshold may be selected.

Next, set the reading condition table in a way that the higher the reading success rate is, the first choice is made. In the example of FIG. 12(B), since the reading success rate becomes the same, for example, as illustrated in FIG. 12(C), the reading condition table can be set in such a way that the polarization state is prioritized and selected first.

The above-mentioned reading process is performed based on the set reading condition table with the switching state and exposure condition as shown in FIG. 12(C) as the switching frequency, for example, it becomes the kind of flow of the timing chart shown in FIG. 10.

As another example, for example, as illustrated in FIG. 13(A), when the reading success rate of the results of the reading test under the four types of exposure conditions A to D is obtained for each of the polarization state and the passing state, Because the reading success rate of exposure condition C is the highest in the polarized state of 90%, and the reading success rate of exposure condition B is the highest in the passing state of 60%, as shown in Figure 13(B), set the polarization state and The exposure condition C becomes 3, the passing state, and the exposure condition B becomes the switching frequency of the ratio of 2. Next, as illustrated in FIG. 13(C), the reading condition table is set in such a way that the polarization state with a higher reading success rate is selected preferentially.

Here, with reference to the timing chart shown in FIG. 14, a detailed description will be given of the flow of the reading process when the switching frequency and the like are set as described above. As shown in FIG. 14, the first exposure by the light-receiving sensor 32 is started in a state where the polarization state is initially set and the exposure conditions (exposure conditions C) suitable for the polarization state are set. After that, after the exposure is completed, the acquisition of the captured image from the light-receiving sensor 32 after the exposure is started. In addition, because the read condition table based on the setting does not need to be switched as described above, the switching has not been started.

Next, when the captured image is stored in the image buffer 1 prepared in the storage unit 22 (refer to t21 in FIG. 14) due to the completion of the acquisition, the interpretation process of the stored captured image is started, and the second of the polarization state and exposure condition C is started. Exposures. After that, when the exposure is over, and the acquisition of the captured image is stored in the image buffer 2 when the above-mentioned interpretation process has not ended (refer to t22 in FIG. 14), the interpretation standby state is entered, and the third time in the polarization state and exposure condition C is started. Of exposure.

Next, after the exposure is completed (refer to t23 in FIG. 14), switching from the polarization state to the passing state is started, and the acquisition of the captured image from the light-receiving sensor 32 after the exposure is completed. Then, since the switching from the polarization state to the passing state is completed and the acquisition of the captured image is completed (refer to t24 in FIG. 14), the first exposure in the passing state and exposure condition B is started. After that, after the exposure is completed, the acquisition of the captured image from the light-receiving sensor 32 after the exposure is started. In addition, because the read condition table based on the setting does not need to be switched as described above, the switching has not been started.

Next, when the captured image is stored in the image buffer 1 prepared in the storage unit 22 (refer to t25 in FIG. 14) due to the completion of the acquisition, the second exposure in the passing state and exposure condition B is started. In addition, when the previous interpretation process has not ended, the interpretation standby state is entered, and since the previous interpretation process ends, the interpretation process is started on the captured image stored in the image buffer.

After that, after the second exposure is completed (refer to t26 in FIG. 14 ), switching from the passing state to the polarization state is started, and the acquisition of the captured image from the light-receiving sensor 32 after the exposure is completed. Then, since the switching from the passing state to the polarization state is completed and the acquisition of the captured image is completed (refer to t27 in FIG. 14), the first exposure in the passing state and exposure condition C is started.

As described above, in the optical information reading device 10 of the present embodiment, the interpretation result of the interpretation processing of the captured image in the polarization state switched by the second polarization section 42 and the interpretation result of the captured image obtained in the passing state The comparison result of the interpretation result of the interpretation process is set by the switching frequency in the second polarization section 42 by the switching frequency and other setting processing performed by the control section 21, and the switching frequency that should be set is performed by the control section 21 in the second Switching of the polarizing section 42.

In this way, in the case where the information codes etc. which should suppress the influence of the specular reflection or the information codes formed on the concave and convex surface are mixed as the reading targets, the switching frequency can be set according to the mixed situation. Therefore, the reading of the information code becomes easy to succeed, and the time for the reading process can be shortened.

Particularly in this embodiment, the interpretation result of the interpretation process obtained every time the polarization condition is changed in the polarization state switched by the second polarizer 42 and the interpretation process obtained every time the polarization condition is changed in the passing state As a result of the comparison result of the interpretation results, the switching frequency and exposure conditions in the second polarizing section 42 are set by the setting processing such as the switching frequency performed in the control section 21. Thereby, the exposure condition setting switching frequency can also be added, the reading of the information code becomes easier to succeed, and the time for the reading process can be further shortened.

In addition, in the above-mentioned second embodiment in which the first polarizing section 41 functions as a switching polarizing section, it responds to the interpretation processing of the captured image obtained from the light-receiving sensor 32 in the first polarization state switched by the first polarizing section 41 The interpretation result and the comparison result of the interpretation result of the interpretation process of the captured image acquired from the light-receiving sensor 32 in the second polarization state may be set in the switching frequency and exposure conditions of the first polarization unit 41.

[Sixth Embodiment] Next, the optical information reading device of the sixth embodiment will be described with reference to the drawings. The sixth embodiment is different from the above-mentioned first embodiment in that it mainly adopts a configuration for suppressing the decrease in the amount of light caused by the polarization of the first polarizing section. Therefore, components that are substantially the same as those of the first embodiment are given the same reference numerals, and the description thereof is omitted.

In this embodiment, in order to suppress the decrease in the amount of light due to polarization in the first polarizing section, instead of the first polarizing section 41 described above, the first polarizing section 41a shown in FIG. 15 is used. The first polarizing section 41a emits most of the incident illuminating light in the predetermined polarization direction, and includes a diffusion section 43 that diffuses (scatters) the illuminating light from the illuminating section 31 and a reflective polarizing section 44. The reflective polarizing part 44, for example, a trade name "DBEF" manufactured by 3M Company, is to transmit light (for example, S-polarized light) in the predetermined polarization direction among the light (randomly polarized light, unpolarized light) diffused by the diffuser 43, leaving the remaining light Light (for example, P-polarized light, etc.) reflected toward the diffuser 43.

With this configuration, the illuminating light incident from the illuminating section 31 to the first polarizing section 41 is diffused in the diffusion section 43, and among the diffused light, light polarized in the predetermined polarization direction passes through the reflective polarizing section 44, and the rest is diffused. Section 43 spread again. Then, among the light diffused again, the light polarized in the predetermined polarization direction passes through the reflective polarizing section 44, and the remaining light is diffused again in the diffuser 43. That is, in the first polarizing portion 41a, most of the illuminating light is repeatedly diffused and transmitted/reflected so as to be aligned with the predetermined polarization direction.

Accordingly, in the optical information reading device 10 of the present embodiment, when the light reflected by the reflective polarizing section 44 is diffused again by the diffuser 43, the light that becomes part of the predetermined polarization direction passes through the reflective polarizing section 44, suppressing Since the amount of light caused by the polarization of the first polarizing portion 41a is reduced, it is possible to easily ensure the amount of illumination light necessary for reading the information code.

In addition, as a configuration for aligning most of the incident illuminating light in the above-mentioned predetermined polarization direction, as described above, it is not limited to the use of the reflective polarization section 44, and other polarization configurations are used, for example, "PG-PCS" manufactured by Colorlink Japan. It's also possible.

In addition, the characteristic configuration of this embodiment can also be applied to other embodiments.

[The seventh embodiment] Next, the optical information reading device of the seventh embodiment will be described with reference to the drawings. In the seventh embodiment, the arrangement configuration of the illuminating part and the first polarizing part is different from the above-mentioned first embodiment mainly. Therefore, components that are substantially the same as those of the first embodiment are given the same reference numerals, and the description thereof is omitted.

In this embodiment, instead of the above-mentioned illuminating unit 31, the illuminating unit 31a shown in FIG. 16 is used. The illuminating unit 31a includes a light source 31b such as an LED that emits illuminating light, and an illuminating lens 31c as a light-collecting element that collects the illuminating light from the light source 31b. The first polarizing unit 41 is arranged between the light source 31b and the light-collecting element 31c. . That is, the first polarizer 41 is arranged between the light source 31b and the illumination lens 31c. In particular, in this embodiment, the first polarizer 41 is arranged between the light source 31b and the illumination lens 31c, and is closer to the light source 31b than the illumination lens 31c.

Because the illuminating light emitted from the light source 31b expands as farther from the light source 31b, the area where the illuminating light enters the first polarizer 41 is compared with the case where the first polarizer 41 is arranged on the emission side of the illuminating lens 31c, that is, The first polarizer 41 should reduce the area where the illumination light is polarized, so that the size of the first polarizer 41 can be reduced. Furthermore, compared with the case where the first polarizer 41 is arranged on the emission side of the illumination lens 31c, in order to be able to keep the illumination lens 31c away from the light source 31b, the light collection effect of the illumination lens 31c is improved, and the information code can be easily secured. Read the necessary amount of illumination light.

In addition, the characteristic configuration of the present embodiment in which the first polarizing section is arranged between the light source and the illumination lens (condensing element) can also be applied to other embodiments. In particular, as in the sixth embodiment described above, in order to improve the polarization efficiency, the reflective polarizing section is used. Since the light emitted from the first polarizing section is easily diffused, the first polarizing section is arranged in the light source and the illumination Between the lenses, the illuminating light irradiated to the information code can be collected effectively.

[Eighth Embodiment] Next, the optical information reading device of the eighth embodiment will be described with reference to the drawings. The present eighth embodiment is different from the above-mentioned first embodiment mainly in that the reading success rate when the information code is read using the optical information reading device configured as described above is notified to the user.

The optical information reading device 10 of this embodiment is a stand-alone reading device. As shown in FIG. 17(A)(B), an outer profile is formed by a box-shaped housing 11, and a control unit 21 is housed in the housing 11 And at least a part of the optical system 30. The display screen 24a of the display unit 24 is arranged in the center of the first surface 11a of the casing 11, and the reading port 12 that absorbs the reflected light from the information code C is arranged in the center of the second surface 11b connected to the first surface 11a.

A pair of light emitting parts 25 are provided on the first surface 11a so as to face each other with the display screen 24a interposed therebetween. In this embodiment, the two light emitting units 25 are controlled by the control unit 21 to emit multiple colors such as blue, green, and red. In addition, on the second surface 11b side of the display screen 24a of the first surface 11a, two push-button switches constituting the operation unit 23 are arranged.

A pair of lighting windows 13a and 13b are provided on the second surface 11b so as to face each other through the reading port 12. In this embodiment, the illuminating unit 31 irradiates the illuminating light through the illuminating window, and one or two or more illuminating units 31 are arranged in each of the illuminating windows 13a and 13b. Particularly in this embodiment, the irradiation state of the illumination light irradiated through the illumination window 13a and the irradiation state of the illumination light irradiated through the illumination window 13b can be individually controlled by the control of the control unit 21.

In addition, in this embodiment, a speaker that is controlled by the control unit 21 to emit various notification sounds such as preset sounds and warning sounds is provided, and the sound hole 14 of the speaker is arranged near the lighting window 13b.

The optical information reading device 10 configured in this way, as shown in FIG. 18, on the conveying line for sequentially conveying the conveyed article R of the additional information code C, the second surface 11b faces the downward conveying line and the first surface 11a faces the user Side configuration. Next, the reading result and the like obtained by the reading process of the imaged information code C performed by the control unit 21 are sent to the host device via the communication interface 26.

Next, the characteristic structure of this embodiment will be described. In this embodiment, by direct marking (DPM), the information code C formed by the concave-convex pattern provided on the display surface (printing surface) of the conveyed article R is used as the reading target. In the information code C formed in this way, in order to ensure a certain reading success rate, various parameters such as exposure conditions and the presence or absence of polarized light, the presence or absence of specular reflection, and the illumination state caused by each illuminating unit 31 are consistent with the information code. C is necessary for adjustment. In addition, even if the initial setting is performed to ensure a certain reading success rate, the reading success rate may gradually decrease without the user noticing it because of changes in the information code caused by environmental changes during future use. . Although a method of quantifying the reading success rate and displaying it on the display screen is also considered, it may be difficult to see the display screen due to the installation environment of the device.

Here, in this embodiment, the reading rate notification processing performed by the control unit 21 is used to report the calculated reading success rate. The user who receives the report can easily recognize the current optical information. The level of the reading success rate of the reading device 10. Among them, the reading success rate, for example, can be calculated based on the number of reading successes when the reading process is repeated in response to a predetermined time with respect to the same information code.

In particular, in this embodiment, the light-emitting state of the pair of light-emitting parts 25 is used to report in accordance with the reading success rate. Specifically, for example, if the reading success rate is at a high level (for example, 90% or more), the two light emitting parts 25 emit blue, and if the reading success rate is at a low level (for example, less than 90%), the two light emitting parts 25 emits red, and a user who sees the light-emitting state of the two light-emitting parts 25 can easily recognize the level of the reading success rate of the current optical information reading device 10.

As a result, the level of the reading success rate can be easily recognized in accordance with the light-emitting state of the light-emitting section 25, and in the initial setting, the exposure conditions and the presence or absence of polarized light, the presence or absence of specular reflection, the illumination state of each illuminating section 31, etc. can be determined. Various parameters are adjusted to a state suitable for reading the information code C. In addition, the same applies to the operation after the initial setting, because the light-emitting state of the light emitting unit 25 changes when the reading success rate decreases, and the decrease in the reading success rate can be easily recognized.

In addition, because the level of the reading success rate is reported in more detail, if the reading success rate is a high level (for example, 95% or more), the two light-emitting parts 25 emit blue, and if the reading success rate is a middle level (for example, 50%) Above 95%), the two light-emitting parts 25 emit green, and if the reading success rate is low (for example, less than 50%), the two light-emitting parts 25 may emit red. In addition, it is not limited to the above-mentioned level for reporting three types of reading success rates with three types of light-emitting states, but it is also possible to report four or more types of reading success rates with four or more types of light-emitting states (including blinking states, etc.). . In addition, the notification is not limited to using the light-emitting state of the pair of light-emitting parts 25, and the notification may be performed using the light-emitting state or the like of other light-emitting parts provided in the housing 11. In addition, in a state where the reading success rate is calculated, both light-emitting parts 25 may be in a non-light-emitting state. In addition, the reading success rate may be in the aforementioned non-luminous state at a low level.

In addition, the relationship between the level of the reading success rate and the light-emitting state of the light-emitting unit 25 may be displayed on the display screen 24a of the display unit 24, the display screen of the host device, or the like. At this time, if the display screen is in color, the above relationship can be expressed in the displayed color, and if the display screen is in monochrome, the above relationship can be expressed in displayed characters.

In addition, in accordance with the interval of the beep sound that is intermittently played through the sound hole 14 by the speaker functioning as a buzzer, the level of the reading success rate may be notified. In addition, the frequency of the beep sound may be changed according to the level of the reading success rate. For example, the higher the reading success rate is, the higher the reading success rate can be by shortening the frequency of the beep (raising the sound). In addition, the level of the reading success rate and the specific value of the reading success rate may be notified by voice.

In addition, the relationship between the level of the reading success rate and the light-emitting state of the light-emitting portion 25 may be changed in accordance with a predetermined operation of the user, the reading of the information code for setting, and the like. Similarly, the relationship between the level of the reading success rate and the beep sound can be changed according to the user's predetermined operation and the reading of the information code for setting.

In addition, the characteristic configuration of the present embodiment that reports the level of the reading success rate can also be applied to other embodiments and the like.

[Ninth Embodiment] Next, the optical information reading device of the ninth embodiment will be described with reference to the drawings. The ninth embodiment is different from the above-mentioned first embodiment in that the second polarizing section is mainly arranged between the imaging lens constituted as a wide-angle lens and the light-receiving sensor.

In this embodiment, instead of the light-receiving optical system 30b described above, the light-receiving optical system 30c shown in FIG. 19 is used. This light-receiving optical system 30c is provided with an imaging lens 33c instead of the imaging lens 33 with respect to the light-receiving optical system 30b.

In order to expand the imaging range of the imaging lens 33c, as shown in FIG. 19, the maximum angle θ1 of the incident light formed on the light sensor 32 is larger than the maximum angle θ2 of the emitted light formed on the light sensor 32. form.

When the second polarizing section 42 acting as the switching polarization section is arranged on the incident side of the imaging lens 33c, the angle of light incident on the switching polarization section becomes larger. The truncation effect of the specular reflection in the peripheral part will be weakened.

Here, in this embodiment, as shown in FIG. 19 for the light receiving optical system 30c, the second polarizing section 42 is arranged between the light receiving sensor 32 and the imaging lens 33c. In this way, compared with the case where the second polarizing section 42 is arranged on the incident side of the imaging lens 33c (upper side in FIG. 19), the angle of the light incident on the switching polarizing section becomes smaller, even if it is used to enlarge the angle of shooting. When a wide-angle lens is used as the imaging lens 33c, it is possible to obtain a specular reflection blocking effect over the entire imaging range.

In addition, the present invention is not limited to the above-mentioned embodiments and the like. For example, it may be embodied as follows. (1) In the above-mentioned first embodiment and the like, the second polarizing section 42 is not limited to being composed of the liquid crystal 50 and the polarizing plate 60, and the reflected light can be switched to be polarized in a direction different from the polarization direction of the first polarizing section 41. The polarization state of the reflected light and the passing state in which the reflected light passes without being polarized may also be configured with another switching polarization unit.

(2) In the above-mentioned second embodiment and the like, the first polarizing section 41 is not limited to being constituted by the liquid crystal 50 and the polarizing plate 60, and the illumination light can be switched between the first polarization state of polarization in the first polarization direction and the illumination light. Another switchable polarization unit configuration in any of the second polarization states polarized in the second polarization direction may be used.

(3) The present invention is not limited to the optical information reading device 10 that has an optical information reading function that reads optical information such as information codes and text information, and is applicable to other functions, such as reading and writing wireless tags, etc. Optical information reading devices with wireless tag communication functions are also possible. In addition, the present invention is suitable for portable information code reading devices and also suitable for placement type information code reading devices.

10: Optical information reading device 21: Control unit (reading unit, detection unit, setting unit) 30: Optical system 31, 31a: Lighting Department 32: Light-receiving sensor (light-receiving part) 41, 41a: the first polarizing part 42: The second polarizing part 50: LCD 51: liquid crystal layer 52, 52b: Alignment film 54: Spacer 60: Polarizing plate C: Information code

[Fig. 1] A block diagram schematically illustrating the structure of the optical information reading device of the first embodiment. [Fig. 2] An explanatory diagram explaining the configuration of the optical system of Fig. 1. [Fig. 3] A plan view showing a schematic configuration of a second polarizing section in Fig. 2. [Fig. 4] A schematic cross-sectional view schematically showing the X-X cross section of the second polarizing section in Fig. 3. [Fig. [Fig. 5] An explanatory diagram for explaining the second polarizing unit used in the optical information reading device of the third embodiment. [FIG. 6] An explanatory diagram for explaining the polarizing part of the conventional alignment film in which the rubbing direction is parallel (perpendicular) to one side of the outer edge with respect to FIG. 5. FIG. [FIG. 7] An explanatory diagram explaining the light-receiving range of the second polarizing section using the liquid crystal of FIG. 5. [FIG. [FIG. 8] An explanatory diagram explaining the light-receiving range of the polarizing section using the liquid crystal of FIG. 6. [FIG. [Fig. 9] Fig. 9 is a flowchart illustrating the flow of the reading process performed by the control unit in the fourth embodiment. [FIG. 10] A timing chart explaining the flow of the reading process when the frequency of switching is set so that the process of acquiring one captured image in the polarized light state and then acquiring one captured image in the passing state is repeated. [Fig. 11] Fig. 11 is a flowchart illustrating the flow of the setting process of switching frequency and the like performed by the control unit in the fifth embodiment. [FIG. 12] FIG. 12(A) is an explanatory diagram showing the reading success rate for each switching state and each exposure condition, and FIG. 12(B) is an explanatory diagram and diagram showing the switching frequency obtained from FIG. 12(A) 12(C) is an explanatory diagram for explaining the reading condition table set based on FIG. 12(B) and the like. [FIG. 13] FIG. 13(A) is an explanatory diagram showing the reading success rate of each switching state and each exposure condition as a condition different from FIG. ) An explanatory diagram of the obtained switching frequency, and FIG. 13(C) is an explanatory diagram illustrating a reading condition table set based on FIG. 13(B) and the like. [FIG. 14] A timing chart explaining the flow of the reading process when the frequency of switching is set to repeat the process of acquiring three captured images in a polarized light state and then acquiring two captured images in a passing state. [Fig. 15] An explanatory diagram for explaining the first polarizing unit used in the optical information reading device of the sixth embodiment. [Fig. 16] An explanatory diagram explaining the arrangement relationship between the illuminating unit and the first polarizing unit used in the optical information reading device of the seventh embodiment. [FIG. 17] An explanatory diagram showing the appearance of the optical information reading device of the eighth embodiment, FIG. 17(A) shows the state seen from the first surface of the housing, and FIG. 17(B) shows the second surface of the housing See the status. [Fig. 18] An explanatory diagram illustrating a state in which the optical information reading device of Fig. 17 is installed on a conveying line. [Fig. 19] An explanatory diagram schematically illustrating the configuration of the light receiving optical system of the optical information reading device of the ninth embodiment.

20a, 20b: circuit board

30: Optical system

30a: Projection optical system

30b: Light-receiving optical system

31: Lighting Department

32: Light-receiving sensor (light-receiving part)

32a: Light-receiving surface

33: imaging lens

34: bracket

41: The first polarizing part

42: The second polarizing part

Claims (21)

An optical information reading device, comprising: an illuminating part that emits illuminating light to an information code; a first polarizing part arranged on the emission side of the illuminating part; a light receiving part that receives reflected light from the information code; and a light receiving part arranged on the light receiving part The second polarizing part on the light-receiving side of the light-receiving part; the reading part that reads the information code in response to the light-receiving result of the light-receiving part; wherein the first polarizing part is constructed in such a way that the illuminating light is polarized in a predetermined polarization direction; the second polarizing light The portion is configured as a switching polarization portion, and can switch between a state where the reflected light is polarized in a direction different from the predetermined polarization direction and a state where the reflected light passes without polarization. The optical information reading device described in claim 1 includes a control unit that controls the switching of the switching polarization unit. The optical information reading device according to claim 2, wherein the first polarizing portion includes a diffusion portion that diffuses the illumination light, and among the light diffused by the diffusion portion, the light in the predetermined polarization direction is transmitted and the remainder A reflective polarizing part that reflects toward the aforementioned diffuser. The optical information reading device according to claim 2 or 3, wherein the light-receiving unit includes a light-receiving sensor, and an imaging lens for imaging an image on the light-receiving surface of the light-receiving sensor; The incident light imaged by the light sensor The maximum angle of is formed to be larger than the maximum angle of the emitted light formed by the light-receiving sensor; the second polarizing part is disposed between the imaging lens and the light-receiving sensor. The optical information reading device according to claim 4, wherein the switching polarization unit is composed of a liquid crystal and a polarizing plate. The optical information reading device according to claim 5, wherein the liquid crystal includes a liquid crystal layer, and a pair of alignment films facing each other and having a rubbing direction different from each other at 90° across the liquid crystal layer; the alignment films are opposed to each other in rubbing directions It is arranged so that one side of the outer edge of the light-receiving surface of the light-receiving part is inclined. The optical information reading device according to claim 5, wherein the liquid crystal includes a liquid crystal layer containing spacers; and the liquid crystal layer has a content ratio of the spacers in a region serving as the light receiving range of the light receiving portion, which is higher than The region in the range where the light-receiving range is different is formed so that the content of the spacer is still low. The optical information reading device described in claim 2 or 3 includes: a detection unit that detects the end of switching at the switching polarization unit; wherein the light receiving unit is controlled by the control unit in response to the detection result of the detection unit After the switching of the above-mentioned switching polarization unit is completed, exposure is started. Such as the optical information reading device described in claim 8, with Prepared: a memory unit that sequentially stores the captured images obtained from the light-receiving unit; the read unit stores the captured images in the memory unit each time, and performs interpretation for interpreting and reading the information codes of the captured images deal with. The optical information reading device according to claim 8, wherein the control section performs switching at the switching polarization section in accordance with a predetermined switching frequency. The optical information reading device described in claim 8 includes: responding to the interpretation result of the captured image obtained from the light-receiving section by the reading section in a state switched by the switching polarization section, and The comparison result of the reading unit's interpretation result of the captured image obtained from the light receiving unit in the other state of the polarization unit switching is set in the setting unit for switching the switching frequency of the polarization unit; The switching frequency set by the section is switched in the switching polarization section. The optical information reading device according to claim 11, wherein the setting section responds to the reading section obtained by changing the exposure condition of the light receiving section in one state switched by the switching polarization section. The interpretation result and the comparison result of the interpretation result of the reading section obtained each time the exposure conditions are changed in another state switched by the switching polarization section are set in the switching frequency of the switching polarization section and the exposure condition. The optical information reading device according to claim 1 or 2, wherein the illuminating unit includes a light source that emits the illuminating light, and The light collecting element that collects the illuminating light from the light source; the first polarizing part is arranged between the light source and the light collecting element. An optical information reading device, comprising: an illuminating part that emits illuminating light to an information code; a first polarizing part arranged on the emission side of the illuminating part; a light receiving part that receives reflected light from the information code; and a light receiving part arranged on the light receiving part The second polarizing part on the light-receiving side of the light-receiving part; the reading part that reads the information code according to the light-receiving result of the light-receiving part; wherein the first polarizing part is configured as a switching polarization part, which can switch the polarization of the illuminating light in the first polarization direction Either the state in which the illumination light is polarized in the second polarization direction; the second polarizing section is configured such that the reflected light is polarized in the second polarization direction. The optical information reading device described in claim 14 includes a control unit that controls the switching of the switching polarization unit. The optical information reading device according to claim 14, wherein the switching polarization unit is composed of a liquid crystal and a polarizing plate. The optical information reading device according to claim 16, wherein the liquid crystal includes a liquid crystal layer, and a pair of alignment films facing each other and having a rubbing direction different from each other at 90° across the liquid crystal layer; the alignment films are opposed to each other in rubbing directions On the light-receiving surface of the aforementioned light-receiving part One side of the outer edge is slanted. The optical information reading device according to claim 17, wherein the liquid crystal includes a liquid crystal layer containing spacers; and the liquid crystal layer has a content ratio of the spacers in the region serving as the light-receiving range of the light-receiving portion, which is higher than It is formed so that the content rate of the said spacer in the area|region of the range different from the said light-receiving range is still low. The optical information reading device according to claim 15, including: a detection unit that detects the end of switching at the switching polarization unit; wherein the light receiving unit is controlled by the control unit in response to the detection result of the detection unit After the switching of the switching polarizer is completed, the exposure starts. The optical information reading device described in claim 19 includes: a memory unit that sequentially stores the captured images obtained from the light receiving unit; The camera image decodes and reads the aforementioned information code. The optical information reading device according to claim 14, wherein the illuminating unit includes a light source that emits the illuminating light, and a light-collecting element that collects the illuminating light from the light source; and the first polarizing unit is disposed between the light source and the light source. Between the aforementioned light-collecting elements.

Images