Optical information reading device and method for manufacturing optical information reading device

Abstract

To provide a structure with which it is possible to easily suppress the deviation of an optical system due to component tolerances or positional tolerances of assembly.SOLUTION: A lens holding part 60 assembled to a holder 50 in which an area sensor 23 is fixed in position is provided with a flange underside 63 as a reference plane which is parallel to a master flat plane along both the optical axis L of an imaging lens 25 and the longer direction (horizontal direction) of a light receiving surface 23a. Meanwhile, the holder 50 is provided with a bottom face 54 as a guide face which the flange underside 63 comes into surface contact with when the lens holding part 60 is assembled so that light via the imaging lens 25 is focused onto the area sensor 23. The bottom face 54 is formed so as to make sliding contact with the flange underside 63 when the lens holding part 60 is moved along the longer direction (horizontal direction) of the light receiving surface 23a.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to an optical information reader that optically reads information codes such as bar codes, and a method for manufacturing the same. [Background technology]

[0002] In recent years, with the spread of two-dimensional codes such as QR Code (registered trademark), there has been an increasing need for retailers, convenience stores, etc. to read two-dimensional codes attached to coupons, etc. For this reason, it is expected that the introduction of reading devices that use area sensors that can also read two-dimensional codes will increase, instead of line sensors dedicated to reading one-dimensional codes. On the other hand, there is still a need to read barcodes, and even devices that can read two-dimensional codes are required to be able to read barcodes.

[0003] In particular, when considering touch reading of barcodes (a reading operation in which the reading port is brought into contact with the barcode) that are wide due to the large amount of recorded information, it is necessary to align the longitudinal direction of the light receiving surface of the area sensor with the longitudinal direction of the reading port, and include the opening area that receives light through the reading port in the imaging field of the area sensor. On the other hand, when component tolerances and assembly position tolerances of optical components such as the imaging lens and the area sensor are overlapped, the imaging field of view shifts with respect to the reading port, and the amount of shift also differs depending on the reading device. It is possible to adopt an area sensor with a wider imaging field of view to allow for the amount of shift, but this would result in a problem of adopting an expensive area sensor, which would increase the manufacturing cost of the reading device.

[0004] As a technique for suppressing deviation of an optical system caused by component tolerances, assembly position tolerances, etc., an optical adjustment mechanism for an image reading device disclosed in the following Patent Document 1 is known, for example. This optical adjustment mechanism is configured to adjust the focus and optical axis of the image reading device by attaching a sensor board of an image sensor (area sensor) to the tip of a support member extending in the optical axis direction of an imaging lens, and slightly moving the fixing position of the support member to which the image sensor is fixed in the optical axis direction by an optical axis direction position adjustment means and slightly moving it parallel to the light receiving surface by a surface direction position adjustment means. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 2886032 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the above-mentioned optical adjustment mechanism, the optical axis direction is adjusted by the optical axis direction position adjustment means, and the direction parallel to the light receiving surface is adjusted by the surface direction position adjustment means, so that the manufacturing process requires a device for adjusting the optical axis direction position and a device for adjusting the surface direction position. This not only increases the number of processes, but also makes the manufacturing related devices large-scale, which makes it difficult to reduce the cost of the reading device. This problem is not limited to the suppression of misalignment between the imaging lens and the area sensor, but also occurs in the suppression of misalignment of other optical systems such as marker light.

[0007] The present invention has been made to solve the above-mentioned problems, and its object is to provide a configuration that can easily suppress misalignment of the optical system caused by component tolerances, assembly position tolerances, etc. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention provides An optical information reader (10) comprising an area sensor (23) in which reflected light from an information code incident through a reading port (13) is received on a light receiving surface (23a) via an imaging lens (25), and the optical information reader (10) optically reads the information code based on a signal output from the area sensor, a holder (50) to which the area sensor is fixed; a lens holding portion (60) that is assembled to the holder while holding the imaging lens; Equipped with The lens holding portion is provided with a reference surface (63) that is parallel to a reference plane that is aligned with both the optical axis (L) of the imaging lens and the longitudinal direction of the light receiving surface, the holder is provided with a guide surface (54) with which the reference surface comes into surface contact when the lens holding portion is assembled so that light passing through the imaging lens forms an image on the area sensor; The guide surface is formed so as to be in sliding contact with the reference surface when the lens holding portion is moved along the longitudinal direction of the light receiving surface. The symbols in parentheses above indicate the corresponding relationship with the specific means described in the embodiments described later. Effect of the Invention

[0009] In the present invention, the lens holding part assembled to the holder to which the area sensor is fixed is provided with a reference surface that is parallel to a reference plane that is along both the optical axis of the imaging lens and the longitudinal direction (hereinafter also simply referred to as the horizontal direction) of the light receiving surface. The holder is provided with a guide surface with which the reference surface comes into surface contact when the lens holding part is assembled so that light passing through the imaging lens forms an image on the area sensor, and this guide surface is formed so as to come into sliding contact with the reference surface when the lens holding part is moved along the longitudinal direction (horizontal direction) of the light receiving surface.

[0010] As a result, when the lens holding part is moved horizontally relative to the holder with the reference surface in surface contact with the guide surface, the reference surface and the guide surface come into sliding contact with each other, so that the horizontal relative position of the imaging lens with respect to the area sensor can be easily and accurately adjusted. Therefore, it is possible to realize an optical adjustment mechanism that can easily suppress horizontal misalignment of the optical system caused by component tolerances, assembly position tolerances, etc., using a simple jig or the like.

[0011] The guide surface may be formed so as to be in sliding contact with the reference plane when the lens holding part is moved along the reference plane, thereby making it possible to easily and accurately adjust not only the horizontal position of the imaging lens relative to the area sensor but also the optical axis direction relative to the area sensor.

[0012] The flange portion of the lens holding part has at least a part of its flat surface facing the imaging lens functioning as a reference surface, and the holder is formed so that when assembled, the part of the lens holding part that is closer to the imaging lens than the flange portion is accommodated through an opening, and at least a part of the flat surface in which this opening is provided may function as a guide surface.

[0013] This not only makes it easy to assemble the lens holding portion to the holder, but also makes it easy to bring the reference surface and the guide surface into surface contact during assembly.

[0014] The flange may be formed so as to cover the opening with a plane that faces the imaging lens when in sliding contact with the opening, whereby the flange functions as a light blocking portion that prevents light from entering through the opening, thereby improving the light blocking property of the holder.

[0015] The lens holding portion is provided with a pair of engagement holes into which an arm engages to move the lens holding portion along the longitudinal direction (horizontal direction) of the light receiving surface, and the pair of engagement holes may be positioned so that, when viewed from a direction perpendicular to the reference plane, the midpoint position between one engagement hole and the other engagement hole coincides with the entrance pupil of the imaging lens.

[0016] The arm engaged with the pair of engagement holes is moved in the horizontal direction to adjust the horizontal relative position of the imaging lens with respect to the area sensor. During this adjustment, due to the clearance for engagement between the arm and the engagement hole, a rotational deviation may occur in a direction along the reference plane based on the midpoint position between one engagement hole and the other engagement hole. Even when such a rotational deviation occurs, the entrance pupil is the rotation center of the imaging lens, so that the deviation of the imaging field of view caused by the rotational deviation can be suitably suppressed compared to the case where the midpoint position is significantly deviated from the entrance pupil of the imaging lens.

[0017] A marker light irradiator that irradiates marker light toward an imaging field of view obtained by the area sensor and the imaging lens may be fixed to the holder.

[0018] As a result, when the lens holding portion is moved horizontally relative to the holder with the reference surface in surface contact with the guide surface, the reference surface and the guide surface come into sliding contact, making it possible to easily and accurately adjust the horizontal relative position of the imaging lens to the marker light irradiation portion, i.e., the irradiation position of the marker light in the horizontal direction in the imaging field of view.

[0019] As a manufacturing method for the optical information reading device of the present invention, a lens holding part holding an imaging lens may be assembled to a holder to which an area sensor is fixed so that the reference surface is in surface contact with the guide surface, and then an arm movable along the longitudinal direction of the light receiving surface is assembled to the lens holding part, and the arm is moved in the longitudinal direction of the light receiving surface so that the reference surface is in sliding contact with the guide surface while sequentially measuring the amount of deviation between the center of the imaging field of view obtained by the area sensor and the imaging lens and a reference point for adjustment, and the lens holding part with the arm assembled thereto is fixed to the holder at a position where the amount of deviation is smallest, and then the arm is removed from the lens holding part.

[0020] As a result, when the lens holding part is fixed to the holder at the position where the above-mentioned deviation amount is smallest, i.e., the relative position where the deviation of the imaging field of view is smallest, the lens holding part is less likely to deviate because an arm is attached to the lens holding part, and adjustment to the optimal relative position determined by measuring the above-mentioned deviation amount can be reliably performed.

[0021] As a manufacturing method for the optical information reading device of the present invention, a lens holding part holding an imaging lens may be assembled to a holder to which an area sensor is fixed so that the reference surface is in surface contact with the guide surface, and then an arm movable along the longitudinal direction of the light receiving surface may be assembled to the lens holding part, and the arm may be moved in the longitudinal direction of the light receiving surface so that the reference surface is in sliding contact with the guide surface while sequentially measuring the amount of deviation between the imaging field of view obtained by the area sensor and the imaging lens and the irradiation range of the marker light irradiated from the marker light irradiator, and the lens holding part with the arm assembled thereto may be fixed to the holder at a position where the amount of deviation is smallest, and then the arm may be removed from the lens holding part.

[0022] As a result, when the lens holding part is fixed to the holder at the position where the above-mentioned deviation amount is smallest, i.e., the relative position where the deviation of the marker light relative to the imaging field of view is smallest, the lens holding part is less likely to deviate because an arm is attached to the lens holding part, and adjustment to the optimal relative position determined by measuring the above-mentioned deviation amount can be reliably performed. [Brief description of the drawings]

[0023] [Figure 1] 1 is a block diagram illustrating a schematic configuration of an optical information reading device according to a first embodiment. [Diagram 2] 1 is an explanatory diagram showing the positional relationship between the opening shape of the reading port and the imaging field of view at the position of the reading port to explain that the longitudinal direction of the light receiving surface and the longitudinal direction of the reading port are aligned. FIG. [Diagram 3] 3A, 3B, and 3C are diagrams showing the configuration of a holder in the first embodiment, with FIG. 3A showing a front view, FIG. 3B showing a plan view, and FIG. 3C showing a side view. [Figure 4]4A, 4B, and 4C are diagrams showing the configuration of a lens holding portion in the first embodiment, with FIG. 4A showing a front view, FIG. 4B showing a plan view, and FIG. 4C showing a side view. [Diagram 5] 5A and 5B are diagrams showing the state in which the lens holding portion is assembled to the holder in the first embodiment, where FIG. 5(A) shows a front view, FIG. 5(B) shows a plan view, and FIG. 5(C) shows a side view with a portion shown in cross section. [Figure 6] 11A and 11B are explanatory diagrams for explaining a relative position adjustment process for each optical unit. [Figure 7] FIG. 11 is an explanatory diagram for explaining relative position adjustment in the X direction. [Figure 8] FIG. 11 is an explanatory diagram for explaining relative position adjustment in the Y direction. [Figure 9] 9A and 9B are explanatory diagrams illustrating the amount of shift in the Y direction between the center of an captured image and a reference point for adjustment within that captured image, where FIG. 9A shows an imaging state in which the reference point is shifted to one side in the Y direction, FIG. 9B shows an imaging state in which the amount of shift is relatively small, and FIG. 9C shows an imaging state in which the reference point is shifted to the other side in the Y direction. [Figure 10] 13A and 13B are explanatory diagrams showing modified examples of the lens holding portion. [Figure 11] 13 is an explanatory diagram for explaining the positional relationship between a pair of engagement holes, which are a main part of an optical information reading device according to a second embodiment, and an entrance pupil of an imaging lens. FIG. [Figure 12] FIG. 12 is an explanatory diagram illustrating the relationship between the positional relationship between a pair of engagement holes and the entrance pupil of the imaging lens and the shift in the imaging field of view due to rotational misalignment. FIG. 12(A) illustrates an example of the imaging field of view when the pair of engagement holes and the entrance pupil of the imaging lens coincide, and FIG. 12(B) illustrates an example of the imaging field of view when the pair of engagement holes and the entrance pupil of the imaging lens are misaligned. [Figure 13] 13A and 13B are explanatory diagrams illustrating a case where the irradiation position of the marker light is misaligned in the third embodiment, where FIG. 13A shows the positional relationship between the marker light and the imaging field of view, and FIG. 13B shows the positional relationship between the barcode aligned with the marker light in FIG. 13A and the imaging field of view. [Figure 14]This is an explanatory diagram showing the amount of shift in the Y direction between the center of an captured image and the marker light within that captured image, where Figure 14(A) shows an imaging state in which the marker light is shifted to one side in the Y direction, Figure 14(B) shows an imaging state in which the amount of shift is relatively small, and Figure 14(C) shows an imaging state in which the marker light is shifted to the other side in the Y direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] [First embodiment] An optical information reader according to a first embodiment of the present invention will now be described with reference to the drawings. The optical information reading device 10 according to the present embodiment is configured as an information code reader that optically reads information codes C such as one-dimensional codes and two-dimensional codes. Here, examples of one-dimensional codes include so-called bar codes such as JAN codes, EAN codes, UPC codes, ITF codes, CODE39, CODE128, and NW-7 codes. Examples of two-dimensional codes include rectangular information codes such as QR codes, data matrix codes, maxicodes, and Aztec codes.

[0025] This optical information reading device 10 has a circuit section 20 housed inside a case not shown, and the circuit section 20 mainly comprises an optical system including an illumination light source 21, a marker light irradiation section 22, an area sensor 23, etc., and a microcomputer (hereinafter referred to as "microcomputer") system including a memory 35, a control section 40, etc.

[0026] The optical system is divided into a light projection optical system and a light receiving optical system. The light projection optical system is composed of an illumination light source 21 and a marker light irradiator 22. The illumination light source 21 functions as an illumination light source capable of emitting illumination light Lf, and is composed of, for example, an LED and a lens provided on the emission side of the LED.

[0027] The marker light irradiating unit 22 functions as a marker light source capable of irradiating marker light Lm indicating the imaging range of the area sensor 23, and is composed of, for example, an LED and a lens provided on the emission side of the LED. Note that Fig. 1 conceptually shows an example in which the illumination light Lf and the marker light Lm are irradiated through the reading port 13 toward the reading object R to which the information code C is attached.

[0028] The light receiving optical system is composed of an area sensor 23, an imaging lens 25, etc. The area sensor 23 is configured to be able to image the information code C as a light receiving sensor having a rectangular light receiving surface 23a in which light receiving elements, which are solid-state imaging elements such as C-MOS or CCD, are two-dimensionally arranged, and is configured to output an electrical signal according to the intensity of the reflected light Lr for each cell (pattern) of the information code received through the reading port 13.

[0029] As shown in Fig. 2, the reading port 13 is formed in a substantially trapezoidal shape so as to have both an elongated opening area S1 for reading a one-dimensional code and an opening area S2 for reading a two-dimensional code. The area sensor 23 is capable of receiving incident light entering through the imaging lens 25, and is mounted on the sensor board 20a so that the longitudinal direction of the light receiving surface 23a is aligned with the longitudinal direction of the reading port 13 (the longitudinal direction of the opening area S1). In Fig. 2, the imaging field of view P at the position of the reading port 13 is illustrated by a rectangular dashed line area.

[0030] The imaging lens 25 is configured to have one or more lenses, and functions as an imaging optical system capable of focusing incident light entering from the outside through the reading port 13 to form an image on the light receiving surface 23a of the area sensor 23. In this embodiment, the illumination light Lf emitted from the illumination light source 21 is reflected by the information code C and the reading object R to which the information code C is attached, and this reflected light Lr is focused by the imaging lens 25 to form a code image on the light receiving surface 23a of the area sensor 23. Note that, for convenience, in FIG. 4 etc., one of the multiple lenses is diagrammatically illustrated as the imaging lens 25.

[0031] 3 to 5, the optical system is provided with a holder 50 to which the sensor substrate 20a is fixed and a lens holding portion 60 to which the imaging lens 25 is held. In the following description, the linear direction perpendicular to the light receiving surface 23a of the area sensor 23 and along the optical axis L of the imaging lens 25 is defined as the X direction (also simply referred to as the optical axis direction), the longitudinal direction of the light receiving surface 23a of the area sensor 23 is defined as the Y direction (also simply referred to as the horizontal direction), and the direction perpendicular to both the X direction and the Y direction (the short side direction of the light receiving surface 23a) is defined as the Z direction.

[0032] As shown in Figs. 3(A) to (C), the holder 50 is substantially box-shaped, and one end 51 is open so that the sensor board 20a can be fixed. The sensor board 20a is fixed so as to cover this opening, so that the area sensor 23 mounted on the sensor board 20a is accommodated in the holder 50. The holder 50 also has an opening 52a centered on the optical axis L at the other end 52 facing the light receiving surface 23a of the area sensor 23. In order to enhance the light blocking property of the holder 50, the opening 52a is formed so as to expose only the imaging lens 25 held by the lens holding part 60 and its vicinity when viewed from the optical axis direction. At least a part of the light projection optical system, such as the illumination light source 21 and the marker light irradiator 22, is also fixed to the holder 50. In this embodiment, the marker light irradiator 22 is fixed to the other end 52 directly below the opening 52a.

[0033] A recess 53 of a predetermined depth is provided in the upper part of the holder 50. The recess 53 is formed so that its rectangular bottom surface 54 is parallel to the XY plane (a plane along both the optical axis L and the longitudinal direction of the light receiving surface 23a: a reference plane). A rectangular opening 55 communicating with the inside of the holder 50 is formed in the center of the bottom surface 54. The bottom surface 54 can correspond to an example of a "guide surface."

[0034] As shown in FIGS. 4(A) to (C), the lens holding portion 60 includes a holding portion main body 61 that holds the imaging lens 25, and a flange portion 62 that extends in a substantially rectangular ring shape from the upper portion of the holding portion main body 61.

[0035] The flange portion 62 is formed so that a flange undersurface 63, which is a flat surface on the imaging lens 25 side, is parallel to the XY plane and can slide in surface contact with the bottom surface 54 of the holder 50. The flange portion 62 is formed so that the Z-direction position of the imaging lens 25 relative to the light receiving surface 23a of the area sensor 23 becomes a specified position when the flange undersurface 63 and the bottom surface 54 are in surface contact. The flange portion 62 has an extension length in the X direction and an extension length in the Y direction set so that the flange undersurface 63 always covers the opening 55 during the sliding contact. A pair of engagement holes 64 are formed on the upper surface of the flange portion 62 and are used when adjusting the relative positions of the lens holding portion 60 and the holder 50. The flange undersurface 63 can be an example of a "reference surface".

[0036] 5(A) to 5(C), when the lens holding part 60 configured in this manner is assembled into the holder 50, the holding part main body 61 of the lens holding part 60, which is closer to the imaging lens than the flange part 62, is housed in the holder 50 through the opening 55, with the flange underside 63 and the bottom surface 54 in surface contact with each other. Then, with the lens holding part 60 adjusted in relative position to the holder 50 in both the X direction and the Y direction, a UV adhesive is applied in the recess 53, etc., to configure an optical unit in which the lens holding part 60 is fixed (secured) to the holder 50.

[0037] The microcomputer system is composed of an amplifier circuit 31, an A / D conversion circuit 33, a memory 35, an address generation circuit 36, a synchronization signal generation circuit 38, a control unit 40, an operation unit 42, a liquid crystal display 43, a buzzer 44, a vibrator 45, a light emission unit 46, a communication interface 48, etc. As the name suggests, this microcomputer system is composed mainly of the control unit 40 and memory 35 that can function as a microcomputer (information processing device), and can process the image signal of the information code captured by the above-mentioned optical system in terms of hardware and software. The control unit 40 also controls the entire system of the optical information reading device 10.

[0038] An image signal (analog signal) output from the area sensor 23 of the optical system is input to an amplifier circuit 31 where it is amplified at a predetermined amplification rate, and then input to an A / D conversion circuit 33 where it is converted from an analog signal to a digital signal. The digitized image signal, i.e., image data (image information), is generated and input to a memory 35, where it is stored in a predetermined code image information storage area. The synchronization signal generation circuit 38 is configured to be able to generate a synchronization signal for the area sensor 23 and the address generation circuit 36, and the address generation circuit 36 ​​is configured to be able to generate a storage address of the image data to be stored in the memory 35 based on the synchronization signal supplied from the synchronization signal generation circuit 38.

[0039] The memory 35 is a semiconductor memory device, such as a RAM (DRAM, SRAM, etc.) or a ROM (EPROM, EEPROM, etc.). The RAM of the memory 35 is configured to reserve not only the code image information storage area described above, but also a work area and a reading condition table used by the control unit 40 during each process such as arithmetic operation and logical operation. The ROM also stores in advance a reading program capable of executing a reading process for optically reading the information code, and a system program capable of controlling each hardware such as the illumination light source 21 and the area sensor 23.

[0040] The control unit 40 is a microcomputer capable of controlling the entire optical information reading device 10, and is composed of a CPU, a system bus, an input / output interface, etc., and can constitute an information processing device together with the memory 35, and has an information processing function. The control unit 40 functions to perform a decoding process on the code image of the information code captured by the area sensor 23 and stored in the memory 35. The control unit 40 is also configured to be connectable to various input / output devices (peripheral devices) via the built-in input / output interface, and in this embodiment, an operation unit 42, a liquid crystal display 43, a buzzer 44, a vibrator 45, a light emitter 46, a communication interface 48, etc. are connected.

[0041] The operation unit 42 is composed of a plurality of keys, and is configured to give an operation signal to the control unit 40 in response to the user's key operation, and the control unit 40 is configured to perform an operation in response to the operation signal when it receives the operation signal from the operation unit 42. The liquid crystal display 43 is composed of a known liquid crystal display panel, and the display content is controlled by the control unit 40. The buzzer 44 is composed of a known buzzer, and is configured to generate a predetermined sound in response to an operation signal from the control unit 40. The vibrator 45 is composed of a known vibrator mounted on a portable device, and is configured to generate vibration in response to a drive signal from the control unit 40. The light emitting unit 46 is, for example, an LED, and is configured to light up in response to a signal from the control unit 40. The communication interface 48 is configured as an interface for performing data communication with the outside (for example, a host device), and is configured to perform communication processing in cooperation with the control unit 40.

[0042] Next, adjustment of the relative positions of the lens holding portion 60 and the holder 50 during the manufacture of the optical unit according to this embodiment will be described. As described above, in order to be able to handle touch reading of a wide range of barcodes, it is necessary to align the longitudinal direction of the light receiving surface of the area sensor with the longitudinal direction of the reading port, while including the opening area that receives light through the reading port in the imaging field of the area sensor. On the other hand, the imaging field of view may be shifted from the reading port due to component tolerances and assembly position tolerances of optical components such as the imaging lens and the area sensor, and if an area sensor with a wider imaging field of view is adopted to allow for the amount of shift, the manufacturing cost of the reading device will increase. In addition to touch reading, it is also necessary to consider the case where a barcode that is somewhat far from the reading port is read. In this case, an area sensor with a wider imaging field of view will have a problem that the number of sensor pixels assigned to one module of the barcode will be reduced, resulting in a shorter reading distance.

[0043] For this reason, in this embodiment, on the premise that there is almost no deviation due to the above-mentioned tolerances, etc., an area sensor 23 is employed in which the width dimension of the imaging field of view P is matched to the width dimension of the elongated opening region S1 of the reading port 13, as shown in Fig. 2. Then, the relative position between the area sensor 23, whose field of view is matched to the reading port 13, and the imaging lens 25, i.e., the relative position between the holder 50 and the lens holding portion 60, is adjusted for each optical unit so as to eliminate the deviation due to the above-mentioned tolerances, etc.

[0044] Hereinafter, a manufacturing method including a relative position adjustment step for each optical unit in this embodiment will be specifically described. First, a step of provisionally assembling the lens holding part 60 holding the imaging lens 25 to the holder 50 to which the area sensor 23 is fixed such that the lower surface 63 is in surface contact with the bottom surface 54 is performed. Then, the provisionally assembled optical unit is placed on a mounting table 102 so that a barcode for adjusting the relative position (hereinafter, also referred to as an adjustment code Ca) displayed on a predetermined display surface 101 can be imaged, as shown in FIG. 6, and a step of assembling a pair of cylindrical engagement parts 104 of an arm 103 movable along the XY plane into both engagement holes 64 of the lens holding part 60 is performed. At this time, the sensor board 20a is connected to a predetermined measuring device 105 so as to be able to output an image signal from the area sensor 23, and information regarding the amount and direction of movement of the lens holding part 60 using the arm 103 is sequentially input to this measuring device 105.

[0045] From this provisionally assembled state, the arm 103 is moved in the X direction so that the lower surface 63 comes into sliding contact with the bottom surface 54, thereby adjusting the relative position of the imaging lens 25 in the X direction (optical axis direction) with respect to the area sensor 23, and a process of sequentially capturing images of the adjustment code Ca by the area sensor 23 is performed. The measuring device 105 sequentially measures the contrast in the code image captured by capturing the adjustment code Ca for each adjusted relative position (see FIG. 7), and moves the lens holding part 60 to the relative position where the contrast is the best.

[0046] When the relative position adjustment (focus adjustment) in the X direction is completed in this manner, a cross-shaped reference marker Pa indicating a reference point for adjustment in the Y direction is displayed on the display surface 101 in place of the adjustment code Ca. This reference marker Pa is set so that the center of the cross shape coincides with the designed optical axis center of the optical unit placed on the mounting table 102. With this reference marker Pa displayed on the display surface 101, the arm 103 is moved in the Y direction so that the lower surface 63 comes into sliding contact with the bottom surface 54, thereby adjusting the relative position of the lens holding part 60 in the Y direction with respect to the holder 50, i.e., the relative position of the imaging lens 25 in the Y direction (horizontal direction) with respect to the area sensor 23, as shown in FIG. 8, and a process of sequentially capturing an image of the reference marker Pa by the area sensor 23 is performed.

[0047] As illustrated in Figures 9(A) to (C), the measuring device 105 sequentially measures the Y-direction shift amount Δy1 between the center Po of the captured image (imaging field of view) and the center position of the reference marker Pa within that captured image for each adjusted relative position, and moves the lens holding unit 60 to the relative position where the shift amount Δy1 is smallest.

[0048] As described above, a process is performed in which the lens holding portion 60 with the arm 103 attached thereto is fixed to the holder 50 by, for example, applying a UV adhesive into the recess 53 of the holder 50 at the optimal relative position where the contrast is best and the deviation amount Δy1 is smallest.

[0049] By removing the arm 103 from the lens holding part 60 after fixing, an optical unit is completed in which the lens holding part 60, whose position has been adjusted in the XY directions (directions along the XY plane), is fixed to the holder 50. In this way, when the lens holding part 60 is fixed to the holder 50 at the optimal relative position, the lens holding part 60 is less likely to shift because the arm 103 is assembled to the lens holding part 60, and adjustment to the optimal relative position determined by measuring the amount of shift Δy1 or the like can be reliably performed.

[0050] As described above, in the optical information reading device 10 according to this embodiment, the lens holding part 60 assembled to the holder 50 to which the area sensor 23 is fixed is provided with the brim underside 63 as a reference surface that is parallel to a reference plane (XY plane) along both the optical axis L of the imaging lens 25 and the longitudinal direction (horizontal direction) of the light receiving surface 23a. The holder 50 is provided with a bottom surface 54 as a guide surface with which the brim underside 63 comes into surface contact when the lens holding part 60 is assembled so that light passing through the imaging lens 25 forms an image on the area sensor 23, and this bottom surface 54 is formed so as to come into sliding contact with the brim underside 63 when the lens holding part 60 is moved along the longitudinal direction (horizontal direction: Y direction) of the light receiving surface 23a.

[0051] As a result, when the lens holding part 60 is moved in the Y direction relative to the holder 50 with the brim underside 63 in surface contact with the bottom surface 54, the brim underside 63 and the bottom surface 54 come into sliding contact with each other, making it possible to easily and accurately adjust the relative position of the imaging lens 25 in the Y direction with respect to the area sensor 23. Therefore, it is possible to realize an optical adjustment mechanism that can easily suppress deviation of the optical system in the Y direction (horizontal direction) caused by component tolerances, assembly position tolerances, etc., with a simple jig such as the arm 103.

[0052] In particular, the bottom surface 54 is formed to be in sliding contact with the flange undersurface 63 not only in the horizontal direction (Y direction) but also when the lens holding part 60 is moved along the XY plane (reference plane). This makes it possible to easily and accurately adjust not only the relative position of the imaging lens 25 to the area sensor 23 in the horizontal direction but also the relative position in the optical axis direction.

[0053] The flange portion 62 of the lens holding portion 60 has a flange underside 63 on the imaging lens side that functions as a reference surface, and the holder 50 is formed so that when assembled, the holding portion main body 61 of the lens holding portion 60, which is on the imaging lens side rather than the flange portion 62, is accommodated through an opening 55, and the bottom surface 54 of the recess 53 in which this opening 55 is provided functions as a guide surface.

[0054] This not only makes it easy to assemble the lens holding portion 60 into the holder 50, but also makes it easier to make surface contact between the brim underside surface 63, which serves as the reference surface, and the bottom surface 54, which serves as the guide surface, during assembly.

[0055] In particular, the flange portion 62 is formed so that the flange underside 63 always covers the opening 55 during sliding contact. This allows the flange portion 62 to function as a light blocking portion that prevents light from entering through the opening 55, thereby improving the light blocking ability of the holder 50.

[0056] The flange 62 is not limited to being formed in a substantially rectangular ring shape so that the flange undersurface 63 always covers the opening 55 during sliding contact, and may be formed so that a part of the opening 55 is exposed. Specifically, for example, the flange 62 may be formed so as to extend in each of the Y directions (left and right directions in FIG. 10) from the upper part of the holder main body 61, as in the lens holder 60a illustrated in FIG. 10. Even in this case, the flange undersurface 63 is parallel to the XY plane and is formed so as to be able to slide in surface contact with the bottom surface 54 of the holder 50, so that the relative position of the imaging lens 25 in the horizontal direction and the optical axis direction with respect to the area sensor 23 can be easily and accurately adjusted. In addition, in order to ensure the light-shielding property of the holder 50 to which the lens holder 60a and the like are fixed, another covering member or the like can be provided so as to cover the opening 55.

[0057] [Second embodiment] Next, an optical information reader according to a second embodiment of the present invention will be described with reference to the drawings. The second embodiment is different from the first embodiment mainly in that the midpoints of a pair of engagement holes for engagement of the arms provided in the lens holding part are arranged to coincide with the entrance pupil of the imaging lens. Therefore, the same reference numerals are used for the components substantially the same as those in the first embodiment, and the description thereof will be omitted.

[0058] As described in the first embodiment, the arm 103 engaged with the engagement hole 64 of the lens holding part 60 at the engagement part 104 is moved along the horizontal direction (or the optical axis direction) to adjust the relative position of the imaging lens 25 with respect to the area sensor 23 in the horizontal direction (or the optical axis direction). In order to smoothly engage the engagement part 104 with the engagement hole 64, it is necessary to provide an engagement clearance that makes the inner diameter of the engagement hole 64 slightly larger than the outer diameter of the engagement part 104.

[0059] Due to this clearance for engagement, during the above adjustment, a rotational deviation may occur in a direction along the reference plane based on the midpoint position between the center of one engagement hole (hereinafter also referred to as engagement hole 64a) and the center of the other engagement hole (hereinafter also referred to as engagement hole 64b). If such a rotational deviation occurs, there is a problem that the imaging field of view may shift, albeit slightly, even if the lens holding part 60 is moved to the relative position obtained as described above.

[0060] For this reason, in this embodiment, as illustrated in Fig. 11, the pair of engagement holes 64 are arranged so that the midpoint position Pm between the center of the engagement hole 64a and the center of the engagement hole 64b coincides with the entrance pupil Ep of the imaging lens 25 when viewed from a direction perpendicular to the reference plane. Specifically, when the focal length of the imaging lens 25 is f, the pair of engagement holes 64 are arranged so that the distance between the midpoint position Pm and the entrance pupil Ep is within a predetermined distance (for example, within a distance of f x 0.1) that is sufficiently short with respect to the focal length f. Note that in Fig. 11, the distance between the center of the engagement hole 64a and the center of the engagement hole 64b is set to D, and the distance between the center of the engagement hole 64a and the midpoint position Pm and the distance between the center of the engagement hole 64b and the midpoint position Pm are illustrated as D / 2, respectively.

[0061] By arranging the pair of engagement holes 64 in this manner, even if the above-mentioned rotational misalignment occurs, the entrance pupil Ep becomes the rotation center of the imaging lens 25 as illustrated in Fig. 12(A). Therefore, compared to the case in which the midpoint position Pm is significantly deviated from the entrance pupil Ep of the imaging lens 25 as illustrated in Fig. 12(B), the shift of the imaging field of view caused by the above-mentioned rotational misalignment can be suitably suppressed. Note that in Fig. 12, for convenience, the shift angle and the like are exaggerated, and in Fig. 12(B), the shift amount of the entrance pupil Ep from the case in which there is no rotational misalignment as a reference (the case in Fig. 12(A) as a reference) is illustrated as ΔSx in the X direction and ΔSy in the Y direction.

[0062] [Third embodiment] Next, an optical information reader according to a third embodiment of the present invention will be described with reference to the drawings. The third embodiment is different from the first embodiment in that the irradiation position of the marker light in the imaging field of view is adjusted. Therefore, the same reference numerals are given to the components substantially the same as those in the first embodiment, and the description thereof is omitted.

[0063] In this embodiment, for the purpose of reducing manufacturing costs, etc., a marker light irradiator 22 is employed in which the length of the marker light Lm in the Y direction matches the length of the imaging field of view in the Y direction. In such a configuration, as illustrated in Fig. 13(A), due to component tolerances and assembly position tolerances of optical components such as the marker light irradiator 22, imaging lens 25, and area sensor 23, the imageable range indicated by the marker light Lm (a range based on both longitudinal ends of the marker light Lm) may be misaligned with the imaging field of view P.

[0064] When such a misalignment occurs, as shown in Fig. 13B, a barcode or the like aligned with the marker light Lm may not fall within the imaging field of view, resulting in poor readability. In other words, the marker light cannot perform its original function, making it difficult to use.

[0065] For this reason, in the process of adjusting the relative position in the Y direction for each optical unit in this embodiment, with the marker light Lm from the marker light irradiator 22 fixed to the holder 50 being irradiated onto the display surface 101, the arm 103 is moved in the Y direction so that the lower surface 63 is in sliding contact with the bottom surface 54. In this manner, the relative position of the imaging lens 25 in the Y direction (horizontal direction) with respect to the marker light irradiator 22 is adjusted, and the process of sequentially capturing images of the marker light Lm by the area sensor 23 is performed.

[0066] For each adjusted relative position, the measuring device 105 sequentially measures the amount of deviation Δy2 between the captured image (imaging field of view) and the irradiation range of the marker light Lm irradiated from the marker light irradiator 22. Specifically, as illustrated in Figs. 14(A) to (C), the measuring device 105 sequentially measures the amount of deviation in the Y direction between the center Po of the captured image (imaging field of view) and the center position of the marker light Lm in the captured image as the amount of deviation Δy2, and moves the lens holding unit 60 to the relative position where the amount of deviation Δy2 is smallest.

[0067] As described above, a process is performed in which the lens holding portion 60 with the arm 103 attached thereto is fixed to the holder 50 by, for example, applying a UV adhesive into the recess 53 of the holder 50 at the relative position where the contrast is best and the deviation amount Δy2 is smallest.

[0068] After the fixing, the arm 103 is removed from the lens holding part 60, whereby an optical unit in which the lens holding part 60, whose position has been adjusted in the XY directions, is fixed to the holder 50, is completed.

[0069] Thus, even in this embodiment, when the lens holding portion 60 is moved horizontally relative to the holder 50 with the brim underside 63 in surface contact with the bottom surface 54, the brim underside 63 and the bottom surface 54 come into sliding contact, so that the relative position of the imaging lens 25 in the Y direction (horizontal direction) to the marker light irradiating portion 22, i.e., the irradiation position of the marker light Lm in the Y direction (horizontal direction) in the imaging field of view, can be easily and accurately adjusted.

[0070] In particular, when the lens holding part 60 is fixed to the holder 50 at the optimal relative position where the deviation of the marker light Lm from the imaging field of view is minimized, the arm 103 is attached to the lens holding part 60. Therefore, the lens holding part 60 is less likely to deviate, and adjustment to the optimal relative position obtained by measuring the deviation amount Δy2 or the like can be reliably performed.

[0071] The present invention is not limited to the above-described embodiments and modifications, and may be embodied as follows, for example. (1) The holder 50 is not limited to having the area sensor 23 and the marker light emitting unit 22, etc., fixed thereto, and may also have other optical system components fixed thereto whose relative positions should be adjusted with respect to the imaging lens 25. In this case, the object is to provide a configuration that can easily suppress deviations in the optical system due to component tolerances, assembly position tolerances, etc., by adjusting the relative positions of the other optical system components and the imaging lens 25 in the Y direction and / or the XY directions.

[0072] (2) The present invention is not limited to being applied to optical information reading devices that optically read information codes, but may also be applied to optical information reading devices that optically read character information, etc. by utilizing a publicly known symbol recognition processing function (OCR), and may also be applied to information reading devices that have other functions in addition to the function of optically reading information codes, etc., such as a wireless communication function for wirelessly communicating with a wireless communication medium.

[0073] 10 Optical information reading device 13 Reading port 23 Area Sensor 23a Photosensitive surface 25 Imaging Lens 50 Holder 53 Recess 54 Bottom surface (guide surface) 55 Aperture 60,60a Lens holder 61 Holding part body 62 Brim 63 Underside of brim (reference surface) 64,64a,64b Engagement hole Ep entrance pupil L optical axis Lm marker light P Imaging field Δy1, Δy2 deviation amount

Claims

1. An optical information reading device comprising an area sensor in which reflected light from an information code incident through a reading port is received on a light receiving surface via an imaging lens, and the optical information reading device optically reads the information code based on a signal output from the area sensor, a holder to which the area sensor is fixed; a lens holding portion that is attached to the holder while holding the imaging lens; Equipped with a reference surface that is parallel to a reference plane that is aligned along both the optical axis of the imaging lens and the longitudinal direction of the light receiving surface is provided on the lens holding portion; the holder is provided with a guide surface with which the reference surface comes into surface contact when the lens holding portion is assembled so that light passing through the imaging lens forms an image on the area sensor, The optical information reading device according to claim 1, wherein the guide surface is formed so as to come into sliding contact with the reference surface when the lens holding portion is moved along the longitudinal direction of the light receiving surface.

2. 2. The optical information reader according to claim 1, wherein the guide surface is formed so as to come into sliding contact with the reference surface when the lens holding portion is moved along the reference plane.

3. The lens holding portion has a flange portion, At least a part of a flat surface of the flange portion facing the imaging lens functions as the reference surface, The optical information reading device described in claim 1, characterized in that the holder is formed so that, when assembled, the portion of the lens holding portion that is closer to the imaging lens than the flange portion is accommodated through an opening, and at least a portion of the plane on which the opening is provided functions as the guide surface.

4. 4. The optical information reader according to claim 3, wherein the flange portion is formed so as to cover the opening with a flat surface that faces the imaging lens during the sliding contact.

5. the lens holder is provided with a pair of engagement holes into which arms are engaged for moving the lens holder along the longitudinal direction of the light receiving surface; An optical information reading device as described in claim 1, characterized in that the pair of engagement holes are arranged so that, when viewed from a direction perpendicular to the reference plane, the midpoint between one engagement hole and the other engagement hole coincides with the entrance pupil of the imaging lens.

6. a marker light irradiating unit that irradiates a marker light toward an imaging field of view obtained by the area sensor and the imaging lens; 2. The optical information reading device according to claim 1, wherein the marker light emitting unit is fixed to the holder.

7. A method for manufacturing an optical information reading device according to any one of claims 1 to 5, comprising the steps of: a step of assembling the lens holding portion, which holds the imaging lens, to the holder, to which the area sensor is fixed, such that the reference surface is in surface contact with the guide surface; a step of assembling an arm movable along a longitudinal direction of the light receiving surface to the lens holding portion; a step of sequentially measuring an amount of deviation between a center of an image pickup field obtained by the area sensor and the imaging lens and a reference point for adjustment while moving the arm in a longitudinal direction of the light receiving surface so that the reference surface is in sliding contact with the guide surface; fixing the lens holding portion to the holder in a state in which the arm is assembled at a position where the amount of deviation is smallest; detaching the arm from the lens holder; 2. A method for manufacturing an optical information reading device, comprising:

8. A method for manufacturing an optical information reading device according to claim 6, comprising the steps of: a step of assembling the lens holding portion, which holds the imaging lens, to the holder, to which the area sensor is fixed, such that the reference surface is in surface contact with the guide surface; a step of assembling an arm movable along a longitudinal direction of the light receiving surface to the lens holding portion; a step of sequentially measuring an amount of deviation between an imaging field of view obtained by the area sensor and the imaging lens and an irradiation range of the marker light irradiated from the marker light irradiator while moving the arm in a direction along the longitudinal direction of the light receiving surface so that the reference surface is in sliding contact with the guide surface; fixing the lens holding portion to the holder in a state in which the arm is assembled at a position where the amount of deviation is smallest; detaching the arm from the lens holder; 2. A method for manufacturing an optical information reading device, comprising:

Images