JP2017091332A - Portable optical reading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a portable optical reading device capable of preventing deterioration of reading performance even when diffuse illumination is performed using a diffuser panel.SOLUTION: A portable optical reading device comprises an imaging unit for imaging an object to be read, an LED illumination device emitting light to a symbol imaged by the imaging unit and a diffuser panel for diffusing light emitted from the LED illumination device. The diffuser panel includes a rear end face on which the imaging unit is disposed and a side face including a light emission surface ES connected to the rear end face so as to surround an imaging axis defining an imaging direction by the imaging unit and having the LED illumination device at the outside thereof and an opposite surface OS opposite to the emission surface ES and the imaging axis, with permeability of illumination light of 70% or higher.SELECTED DRAWING: Figure 18

Description

  The present invention relates to a portable optical reader capable of preventing a decrease in contrast of image data obtained by an image sensor, and thus preventing a decrease in reading performance.

  Conventionally, a hand-held handy scanner is known as a device for reading a symbol attached to a product or a packaging box. This handy scanner irradiates a symbol such as a two-dimensional code with light emitted from a light source such as an LED, receives the reflected light, and reads the symbol based on image data obtained by an image sensor such as a CCD. There are types.

  In addition, a technique for improving the symbol reading performance is known for this handy scanner by irradiating diffuse lighting with high uniformity from the reading port of the handy scanner using a diffusion plate. For example, in Patent Document 1, as shown in FIG. 29, the optical information reader 1001 emits marker lights MK1 and MK3 made of diffused light at the first marker light irradiation unit 1050a and the second marker light irradiation unit 1050c. It is configured as follows.

  In addition, a technique is known for a handy scanner that improves symbol reading performance by providing a plurality of light sources around a reading optical axis, blocking the plurality of light sources, lighting the blocks, and switching the illumination direction ( For example, see Patent Document 2.)

JP 2011-60101 A JP-T-2002-525729

  Here, it is considered that a plurality of light sources arranged outside the dome-shaped diffuser plate are turned on in blocks, and a partial diffuse illumination is applied to the symbol. In this case, light emitted from the block-lit light source is diffused when passing through the dome-shaped diffusion plate, and uniform illumination can be applied to the symbol from a specific direction.

  However, when the light diffused by the diffuser is reflected by the diffuser at the position facing the block-lit light source, and the reflected light is applied to the symbol, the contrast of the image data obtained by the image sensor is reduced. There's a problem.

  The present invention has been made in view of such conventional problems. An object of the present invention is to provide a portable optical device capable of preventing a decrease in contrast of image data obtained by an image sensor and thus a decrease in reading performance even when diffusing illumination is performed using a diffusion plate. To provide a reader.

Means for Solving the Problems and Effects of the Invention

  According to the portable optical reader according to the first aspect of the present invention, the imaging unit that images the symbol to be read, the light source that emits light to the symbol imaged by the imaging unit, and the light emitted from the light source A diffusion member that diffuses the emitted light, a head unit that houses the imaging unit, the light source, and the diffusion member, and a grip that is connected to the head unit and extends in the connection direction and is gripped by a user The diffusing member is connected to the rear end surface disposed in front of the imaging unit in the head unit and the rear end surface so as to surround the imaging axis of the imaging unit. A first side surface disposed so that the light source is positioned outside the diffusing member, and a side surface including the second side surface facing the first side surface across the imaging axis, The transmittance of the second side surface is 70% or more There, the transmittance of the first aspect can be configured so that 90% or less. By the said structure, the transmittance | permeability of a 2nd side surface can be suppressed by increasing the transmittance | permeability of a 2nd side surface with 70% or more, On the other hand, the transmittance | permeability of a 1st side surface shall be 90% or less. The uniformity of diffused light on the first side can be ensured. That is, while enjoying the advantages of diffused light, it is possible to suppress the adverse effects of reflected light and prevent the reading performance from being lowered.

  Further, according to the above configuration, as the shape of the diffusing member that may exist on the side surface surrounding the imaging axis with the first side surface and the second side surface facing each other, for example, a dome shape, a truncated cone and a truncated pyramid A frustum shape such as can also be included.

  According to the portable optical reader according to the second aspect of the present invention, the light source can be turned on only in some blocks when the side surface of the diffusing member is divided into a plurality of blocks in the circumferential direction. One side surface of a pair of blocks facing each other across the imaging axis among the plurality of blocks is the first side surface, and the other side surface is the second side surface. It can be configured as follows. With the above-described configuration, so-called block lighting is possible, and it is possible to wait for the relationship of the transmittance at which the reading result is good in units of opposing blocks.

  According to the portable optical reader according to the third aspect of the present invention, the diffusing member is formed in a substantially quadrangular pyramid shape, and the side surface is stepped upward in the head portion direction of the grip portion. An upper side surface portion that is open or gradually opened, a right side surface portion and a left side surface portion that are connected to the upper side surface portion, and a continuous connection to the right side surface portion and the left side surface portion that are substantially parallel to the imaging axis. And a lower side surface portion located below the shaft. With the above configuration, the diffusing member has a substantially quadrangular pyramid shape and opens as the diameter of the diffusing member surrounding the periphery of the imaging axis moves away from the imaging unit. The upper side surface portion is gradually or upwardly opened upward, so that diffused light can be emitted from the direction closer to the vertical with respect to the reading target, while the lower side surface portion is substantially parallel to the imaging axis. Therefore, the diffused light can be emitted obliquely with respect to the reading target. Thereby, dark field illumination can be realized from the lower side surface portion below the head portion, and bright field illumination can be realized from the upper side surface portion above the head portion. Therefore, in combination with the block lighting, the reading operation can be performed under illumination conditions according to the properties of the reading target, and the accuracy of the reading result is improved.

  According to the portable optical reader according to the fourth aspect of the present invention, the entire side surface of the diffusing member can be configured to have a transmittance of 70% to 90%. With the above configuration, the transmittance of the diffusing member can be made uniform between 70% and 90%, so that the transmittance of both the first side surface and the second side surface satisfies 70% to 90%. The diffusion member can be molded from

  According to the portable optical reading device of the fifth aspect of the present invention, the relationship of the transmittance of the second side surface to the first side surface is at least the relationship of the transmittance of the left side surface portion to the right side surface portion, Configuration that matches with any one of the relationship of the transmittance of the right side surface portion with respect to the left side surface portion, the relationship of the transmittance of the lower side surface portion with respect to the upper side surface portion, or the relationship of the transmittance of the upper side surface portion with respect to the lower side surface portion. it can. With this configuration, it is possible to provide variations in the illumination conditions when performing the reading operation.

  According to the portable optical reader according to the sixth aspect of the present invention, the relationship of the transmittance of the second side surface to the first side surface is at least the relationship of the transmittance of the lower side surface portion to the upper side surface portion, Or it can comprise so that it may match with any one of the relationship of the transmittance | permeability of the upper side part with respect to the said lower side part. With the above configuration, while enjoying the advantages of diffused light while appropriately selecting two illumination conditions, dark field illumination from the lower side surface below the head portion and bright field illumination from the upper side surface above the head portion, reflection The adverse effects of light can be suppressed.

  According to the portable optical reader of the seventh aspect of the present invention, the outer side of the second side surface can be made of a material that absorbs light so as to absorb diffused light that has passed through the first side surface. By the said structure, it can prevent that the light which passed the 2nd side surface reflects and returns on the outer side of a 2nd side surface.

  According to the portable optical reader of the eighth aspect of the present invention, the imaging unit that images the symbol to be read, the light source that emits light to the symbol imaged by the imaging unit, and the light emitted from the light source A diffusion member that diffuses the emitted light, a head unit that houses the imaging unit, the light source, and the diffusion member, and a grip that is connected to the head unit and extends in the connection direction and is gripped by a user The diffusing member is connected to the rear end surface disposed in front of the imaging unit in the head unit and the rear end surface so as to surround the imaging axis of the imaging unit. And a side surface including a first side surface disposed so that the light source is located outside the diffusing member, and a second side surface facing the first side surface with the imaging axis interposed therebetween. With a reflectance of less than 30% on the second side surface There, the transmittance of the first aspect can be configured so that 90% or less. With the above-described configuration, for example, when light is absorbed by the diffusing member, the reflectance is less than 30% even when the transmittance and the reflectance are not in a complementary relationship (reflectance ≠ 100% −transmittance). Since it is lowered, the adverse effect of reflected light can be suppressed and the reading performance can be prevented from deteriorating.

It is a schematic diagram which shows the structure of the handy scanner which concerns on one Embodiment of this invention. It is a front view of a handy scanner. It is a right view of a handy scanner. It is a rear view of a handy scanner. It is a figure which shows the state which connected the charging unit and the handy scanner. It is a figure which shows the state which removed the charging unit from the handy scanner. It is a figure which shows the state which took out the battery from the handy scanner. It is the elements on larger scale of the connection location seen from the right side direction when a handy scanner and a charge unit are in a connection state. It is a structural diagram showing an internal configuration of the handy scanner. FIG. 10 is a structural diagram showing an internal configuration of the handy scanner, viewed from an angle different from FIG. 9. FIG. 11 is a structural diagram showing an internal configuration of the handy scanner, viewed from an angle different from FIGS. 9 and 10. It is a block diagram which shows the hardware constitutions of a handy scanner. It is a block diagram which shows the hardware constitutions for supplying electric power to the main board in a power supply board. It is a front view of the head part of a handy scanner. It is a schematic diagram of the illumination board | substrate of a handy scanner. It is explanatory drawing of the optical path in case a diffusing plate does not permeate | transmit. It is the digital image imaged in the illumination environment which a diffuser plate does not permeate | transmit. It is explanatory drawing of the optical path in case a diffusing plate permeate | transmits. It is the digital image imaged in the illumination environment which a diffuser plate permeate | transmits. It is explanatory drawing of the place which uses a member with a high transmittance | permeability in a diffusion plate. It is explanatory drawing of the place which uses a member with a high transmittance | permeability in a diffusion plate. It is sectional drawing seen from the right side surface of the handy scanner. It is the elements on larger scale which looked at the head part of the handy scanner from the right side. It is explanatory drawing of the diffusion plate of a handy scanner. It is explanatory drawing of the diffusion plate of a handy scanner. FIG. 26A is a diagram viewed from the outside of the head unit, and FIG. 26B is a diagram viewed from the inside of the head unit. It is explanatory drawing for showing that the transmittance | permeability is raising uniformly in all the site | parts of a diffusion plate, maintaining a diffusivity. It is explanatory drawing for showing that the transmittance | permeability is raising only the one part site | part of the opposing surface which opposes the light emission surface of a diffusion plate. It is a schematic diagram which shows the conventional optical information reader.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a portable optical reader for embodying the technical idea of the present invention, and the present invention does not specify the portable optical reader as follows. Further, the present specification by no means specifies the members shown in the claims to the members of the embodiments. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the embodiments are not intended to limit the scope of the present invention unless otherwise specified, and are merely explanations. It is just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing.

  The basic principle of a portable optical reader (hereinafter also referred to as a handy scanner) is that a laser beam is irradiated, and the symbol of a bar code or the like (hereinafter also referred to as a bar code or a code as an example) by the intensity of reflected light. Identifying. In recent years, a two-dimensional code (QR code (registered trademark), etc.) has become common in mobile phones and smartphones, and this type cannot be scanned with laser light, but is mainly captured as an image with a camera. The code is identified by analyzing the image.

  Broadly divided into a laser type and a camera type, and further divided into a fixed type and a handheld type. The fixed type is not generally handled in daily life, but the fixed type may be used in an automated line for traceability, for example, in a factory. The hand-held type may be used in the daily life, such as a cash register, or in a factory where people are involved.

  When further classified, there are a one-dimensional barcode and a two-dimensional barcode depending on the type of code. Many of them read what is printed on paper and labels, but some of them are printed with laser markers on metal products and parts such as direct engines that are generally called direct parts marking (DPM). There are also portable optical readers that read it.

  The portable optical reader according to the present invention is a type in which a user performs a reading operation by hand. The object of application may vary widely from consumer products to DPM, and is not particularly limited.

  Note that the symbols include one-dimensional codes and two-dimensional codes, as well as composite symbols obtained by combining these. The one-dimensional code is also called a bar code or a one-dimensional symbol, and examples thereof include Code 39 and Code 128.

  The two-dimensional code is also referred to as a two-dimensional bar code, a two-dimensional symbol, and the like. And MaxiCode.

The composite symbol includes a GS1 composite symbol in which a one-dimensional code and a two-dimensional code are mixed. The GS1 composite symbol can use three types of EAN / UPC (EAN-13, EAN-8, UPC-A, UPC-E), GS1-128, and GS1 data bars as a one-dimensional code as a base. Further, as the additional information, MicroPDF417 or a two-dimensional code of PDF417 can be used. This embodiment can also be applied to a combination of a barcode and a matrix type two-dimensional code such as a micro QR code.
(Configuration of Handy Scanner 1)

  FIG. 1 is a schematic diagram showing a configuration of a handy scanner 1 according to an embodiment of the present invention. In this figure, the symbol IL indicates illumination light. Hereinafter, for the sake of convenience, the direction viewed from the reading port 4 side of the handy scanner 1 is the front, the direction viewed from the head unit 3 side is a plane, and the direction viewed from the end surface side of the gripping unit 2 is the bottom surface. And define. Further, the hand scanner 1 with the reading port 4 is defined as the front side and the opposite side is defined as the rear side.

  2 is a front view of the handy scanner 1, FIG. 3 is a right side view thereof, and FIG. 4 is a rear view thereof. As shown in FIGS. 1 to 4, the handy scanner 1 has a rectangular reading port 4 for reading a barcode at the upper part of the front surface, and both side surfaces and a plane are continuous from the reading port 4 to the back surface. A head portion 3 is provided and formed. Further, a grip portion 2 is provided which is connected to the head portion 3 and extends in the continuous direction, that is, the bottom surface direction, and is gripped by the user so that the outer shape thereof is a rod shape having a substantially circular cross section.

  An end surface is formed in the bottom surface direction of the grip portion 2, and the charging unit connection portion 11 is disposed there. The charging unit 101 is connected to the charging unit connection unit 11. FIG. 5 is a diagram illustrating a state where the charging unit 101 is connected to the handy scanner 1. FIG. 6 is a view showing a state where the charging unit 101 is detached from the handy scanner 1. As shown in these drawings, the handy scanner 1 can be used with the charging unit 101 connected, or the handy scanner 1 can be used as a cordless unit.

  The driving power for driving the handy scanner 1 is supplied from the battery 5 or the charging unit 101, but when both can be supplied, the higher voltage is given priority. Supplied. As shown in this figure, the user can read the barcode without worrying about the state of charge of the battery 5 while the handy scanner 1 is connected to the charging unit 101 or whether or not the battery 5 is present. It can be carried out.

  FIG. 7 is a diagram illustrating a state in which the battery 5 is removed from the handy scanner 1. As shown in this figure, the battery 5 has a cylindrical shape. For example, a lithium ion battery is used, and the battery lid 6 is closed and the battery 5 is housed inside the grip portion 2. A battery lid lock 7 is provided below the battery lid 6 in FIG. 7, and the battery lid 6 is configured to open when pressed.

  FIG. 8 is a partially enlarged cross-sectional view of a connection portion viewed from the right side surface direction when the handy scanner 1 and the charging unit 101 are in a connected state. As shown in this figure, a claw is formed at the tip of the battery lid lock 7. When the battery lid lock 7 is closed, the claw is hooked on the protrusion 8 formed at the end of the battery lid 6. When the battery lid lock 7 is pressed, the claw at the tip is released and the battery lid 6 is opened. The battery lid lock 7 is configured so that the handy scanner 1 and the charging unit 101 are unlocked simultaneously with the opening of the battery lid 6. Thereby, the electric power feeding by the charging unit 101 at the time of replacement | exchange of the battery 5 can be avoided.

  9 to 11 are structural diagrams showing the internal configuration of the handy scanner 1. As shown in these drawings, the handy scanner 1 mainly includes a front case 43, a reading unit 41, a battery unit 42, a rear case 44, and a charging unit connection unit 11.

  As shown in FIGS. 9 to 11, the reading unit 41 projects LED illumination 2915 (not shown) for projecting the LED illumination light IL to the reading target via the reflector 36 and the light projecting polarization element 242 of the polarization element 24. LED illumination 2911 to LED illumination 2914 (not shown) for emitting diffused light IL from the side surface to the reading object via the diffusion plate 23, and LED illumination 2911 to LED illumination 2915. A light projection unit 46 including a lighting board 29 for controlling the light source and a reflection plate 28 for efficiently reflecting reflected light useful for reading, a camera frame 32, a camera cover 30, and reflected light from a reading target Is received through the light receiving polarizing element 241 of the polarizing element 24 that is 90 ° out of phase with the light projecting polarizing element 242, and the light receiving lens 31 A light receiving unit 47 including a CMOS image sensor 34 for creating a digital image from the formed light image, a trigger switch 25 for operation by a user, a trigger packing 26, and a function switch 50 for switching to various modes. Including an operation unit 48 including a vibrator 27 for notifying a user of various information, an indicator LED 21 (not shown), and an indicator lens 22, and reading results as PLC (Programmable Logic Controller) or PC For example, a communication unit (not shown) for wireless communication such as Bluetooth (registered trademark) with a separate communication unit (not shown) for transmission to (Personal Computer). A main base for controlling the light unit 46, the light receiving unit 47, the operation unit 48, the notification unit 49, and the communication unit. 33, and a power board 37 for supplying power to the various members as the main unit.

  The battery unit 42 includes a 3.7V battery 5 having a cylindrical shape, a battery lid 6 for housing and closing the battery 5, and a battery charge controller 35 for supplying power from the battery 5 to the main board 33. I have.

The front case 43 and the rear case 44 accommodate the reading unit 41 and the battery unit 42, and they are combined to form a housing. A charging unit connection portion 11 is disposed on an end surface of the grip portion 2 of the housing.
(Circuit block of handy scanner 1)

  FIG. 12 is a block diagram illustrating a hardware configuration of the handy scanner 1. As shown in FIG. 12, the main board 33 includes a DSP 331 and the like, and controls the operations of the light projecting unit 46, the light receiving unit 47, the operation unit 48, and the notification unit 49 of the handy scanner 1. The reading process is executed on the device. The main board 33 operates the communication unit and transmits the reading result to the communication unit.

  When the DSP 331 detects that the trigger switch is turned on based on the program and setting stored in the ROM 332 (or expanded in the RAM 333), the LED lighting 2911 to the LED lighting 2915 are transmitted via the LED driver 292. Control is made to light up in the set mode. For example, LED lighting 2911 to LED lighting 2914 are respectively arranged on the back of the diffuser plate 23 on the circumference to form blocks, and lighting is controlled for each block. By this block lighting, it is possible to illuminate the barcode from a specific direction while using diffuse illumination. Details of block lighting will be described later.

  Subsequently, in the DSP 331, the CMOS image sensor 34 stores the image data in the RAM 333, and performs a decoding process based on the image data stored in the RAM 333. When the reading process is completed, the communication unit is controlled to output a reading result by Bluetooth (registered trademark). In addition, the DSP 331 emits a sound indicating that reading is normally completed from the buzzer 51 via the buzzer driver 511, and simultaneously operates the vibrator 27 via the motor driver 271. Furthermore, the DSP 331 turns on the indicator LED 21 via the indicator driver 211 to notify the user of the completion of reading and various progresses.

  FIG. 13 is a block diagram showing a hardware configuration for supplying power to the main board 33 in the power supply board 37. A system for supplying power from the charging unit 101 connected to the AC adapter via the electrical contact 12 is applied with a predetermined voltage, and a system for supplying power from the battery 5 is applied with a predetermined voltage. In the power supply board 37, the switch 52 and the battery charge controller 35 are arranged in parallel so that the battery 5 can be charged via the battery charge controller 35 or power can be supplied to the main board 33 via the switch 52. . When the charging unit 101 is connected to the handy scanner 1 and the battery 5 is inserted in the handy scanner 1, that is, when both are connected, power is normally supplied from the charging unit 101 to the main board 33. Will be. In this case, when the voltage of the battery 5 is lower than a predetermined voltage, the battery 5 is charged.

When the charging unit 101 is not connected to the handy scanner 1, power is supplied from the battery 5. When the battery 5 is not inserted in the handy scanner 1, power is supplied from the charging unit 101.
(Block lighting)

  As one means for reading a bar code with high obfuscation, there is block lighting in which illumination light is turned on in blocks. FIG. 14 is a front view of a portion of the head unit 3. With this block lighting, as shown in this figure, the diffusion plate 23 (corresponding to an example of the “diffusion member” in the claims) is connected to the upper side surface portion 231, the left side surface portion 232, the lower side surface portion 233, the right side surface portion. 234 can be divided into four blocks and each can be arbitrarily lit in blocks. Therefore, it is possible to illuminate the barcode from a specific direction by lighting a specific block.

  FIG. 15 is a schematic diagram of the illumination substrate 29 disposed behind the diffusion plate 23. As shown in FIG. 15, the illumination board 29 includes an LED illumination 2911, an LED illumination 2912, and an LED illumination so as to correspond to the upper side surface portion 231, the left side surface portion 232, the lower side surface portion 233, and the right side surface portion 234. 2913 and LED lighting 2914 are provided. In the LED lighting 2911 to LED lighting 2914, for example, four LEDs emitting blue light are arranged on the lighting board 29, respectively. This LED has an emission angle of about 120 ° and emits LED illumination light IL in a broad shape. The LED illumination light IL is diffused when passing through the diffusion plate 23, and becomes diffused light with uniform luminance. Details of the diffusion plate 23 will be described later.

  One of the roles of this block lighting is to change the zenith angle of the illumination light. For example, by illuminating the lower side surface portion 233 substantially parallel to the imaging axis in blocks, diffused light can be emitted obliquely with respect to the barcode, and the upper side surface portion 231 opened upward is block lit. Diffuse light can be emitted from a direction closer to the vertical with respect to the cord.

  The advantage of changing the zenith angle of the illumination light is that when the barcode is marked with scratches, such as direct part marking (DPM), the periphery of the barcode is rough like a satin or casting surface. In this case, when the diffused light is applied obliquely, it may be diffusely reflected on the rough surface, and it may be read well by receiving the reflected light at the marked location, while the bar code is like a mirror surface If the incident light is likely to be reflected, it may be better read when the diffused light is applied from a direction closer to the vertical. In other words, when the barcode reading characteristics vary depending on the zenith angle of the illumination light, it is possible to read well by selecting the optimum zenith angle.

  Another role of block lighting is to change the azimuth angle of illumination light. For example, since an upper side surface portion 231, a lower side surface portion 233, a left side surface portion 232, and a right side surface portion 234 are arranged on the upper, lower, left, and right sides of the imaging axis, respectively, Diffuse light can be emitted from the cord at different azimuth angles.

The advantage of changing the azimuth angle of the illumination light is that, for example, a hairline-like reading object that has been subjected to direct part marking (DPM) may not be read well even if illumination light is applied perpendicular to the line direction of the hairline. On the other hand, even in such a case, if illumination light is applied in the direction of the hairline, it may be satisfactorily read. In other words, when the barcode reading characteristics vary depending on the azimuth angle of the illumination light, it is possible to perform good reading by selecting an optimum azimuth angle.
(Configuration of diffusion member)

  Consider a case where the LED illumination 291 is turned on from behind the diffuser plate 23 to light the block. For example, as shown in FIG. 16, when the lower side surface portion 233 is block-lit, the LED illumination light emitted from the LED illumination 2913 is diffusely reflected when passing through the lower side surface portion 233 of the diffuser plate 23, thereby increasing the luminance. Uniform diffuse light. In this figure, the lower side surface portion 233 is the light emitting surface ES (corresponding to an example of “first side surface” in the claims), and the upper side surface portion 231 facing the lower side surface portion 233 is the opposing surface OS (patent). This corresponds to an example of the “second side surface” in the claims). The diffused light from the light emitting surface ES hits the barcode as it is and can be read well if the reflected light can be received and imaged. However, as shown in FIG. 16, a part of the diffused light strikes the opposing surface OS. When the light reflected by the facing surface OS hits the barcode, the diffused light is applied from a specific direction by turning on the block, and although it is desired to increase the contrast, it is affected by the reflected light from the facing surface OS, and FIG. As shown in FIG. 2, the contrast of the barcode is lowered.

  On the other hand, if the reflection on the facing surface OS can be suppressed, the diffused light traveling from the facing surface OS toward the barcode can be reduced, and the contrast can be prevented from decreasing. As a method for suppressing the reflection on the facing surface OS, as shown in FIG. 18, the diffused light from the light emitting surface ES is transmitted through the facing surface OS as it is, and the transmittance of the facing surface OS is, for example, 70 As a result, the diffused light traveling from the facing surface OS toward the barcode can be reduced, and the contrast of the barcode can be increased as shown in FIG.

  On the other hand, it is preferable that the transmittance of the light emitting surface ES is kept at 90% or less so that at least diffused light can be emitted. This is due to the following reason. In the diffusion plate 23, a granular diffusion material is mixed in a transparent resin, and the incident LED illumination light is scattered by the diffusion material, and diffused light with uniform brightness can be obtained. This is because it is necessary to reduce the amount of the diffusing material, and it becomes impossible to emit diffused light with sufficiently uniform luminance.

  In the present embodiment, the diffuser plate 23 has both the role of the light emitting surface ES and the role of the facing surface OS by turning on the block. As shown in FIG. 20, there are a case where the lower side of the head part is the light emitting surface ES and the upper side of the head part is the opposing surface OS, and a case where the upper side of the head part is the light emitting surface ES and the lower side of the head part is the opposing surface OS. Further, as shown in FIG. 21, there are a case where the right side of the head part is the light emitting surface ES and the left side of the head part is the opposing surface OS, and a case where the left side of the head part is the light emitting surface ES and the right side of the head part is the opposing surface OS. . Therefore, the transmittance of the diffusion plate 23 is uniformly 70% or more and 90% or less. Accordingly, the transmittance of both the light emitting surface ES and the facing surface OS satisfies 70% to 90%, and the diffusion plate 23 can be formed from one material.

On the other hand, in the case where the facing surface OS does not have to be configured by a diffusion plate, for example, it may be configured by a member that transmits all of the illumination light emitted from the light emitting surface ES, or is completely absorbed. You may comprise with a member. As described above, the transmittance of 70% or more of the facing surface OS may be replaced with the reflectance of the facing surface OS of less than 30%. In order to more effectively prevent reflection at the facing surface OS, the reflectance is preferably less than 20%, more preferably less than 10%. The reflectance and transmittance are preferably measured according to JIS standard K7375.
(Combination structure of diffuse illumination and polarized illumination)

  Polarized illumination is to block light other than light that is polarized in a specific direction with a polarizing element for light projection, and to block light other than light that is polarized in a specific direction with a 90 ° phase difference with a polarizing element for light reception. Therefore, since the polarized light is transmitted between the two polarizing elements, the amount of light is halved by interposing one polarizing element. 1/4 of this. Therefore, conventionally, when both diffuse illumination and polarized illumination are used in an image processing apparatus or the like, a light source that can increase the amount of light emission, such as an annular light source, is adopted for the polarized illumination, In this case, if a polarizing element for light reception is interposed, the amount of light becomes ½ of the amount of emitted light. Therefore, it is desirable to capture images with different light paths for diffuse illumination and polarized illumination. There was a problem that it was constituted as a separate body and the apparatus using these would be enlarged.

If the handy scanner is used in combination with diffuse illumination and polarized illumination, it is necessary to make it compact due to the nature of the handy scanner. In order to use the diffused illumination and the polarized illumination well together while reducing the size of the head portion, in the present embodiment, first, the projection light of the polarized illumination is projected on the rear end surface (rear surface) of the quadrangular pyramid-shaped diffuser plate 23. An opening 2432 for receiving polarized light is provided in the vicinity thereof. Further, the diffuse illumination is performed by the upper side surface portion 231 to the right side surface portion 234 which are the side surfaces of the quadrangular pyramid-shaped diffusion plate 23, and the optical path to the imaging unit 41 is shared by the diffuse illumination and the polarized illumination. As a result, the light receiving polarization element 241 intervenes even in diffuse illumination, but by adopting the high-power LED illumination 2411 to LED illumination 2415 as the light source, the problem of the light quantity is solved, and Combined with the advantage that the imaging unit 41 can capture an image, the head unit 3 can be made compact.
(Example)

  Based on these, the internal structure of the head unit 3 and the diffusion plate 23 are set as the following embodiments. FIG. 22 is a cross-sectional view of the handy scanner 1 as viewed from the side. FIG. 23 shows a partially enlarged view in which the head portion 3 of FIG. 22 is enlarged. As shown in these drawings, a substantially square frustum-shaped diffusing plate 23 is accommodated in the head portion 3, and a light receiving lens 31 that forms a light image at the upper base position of the frustum and an image from the light image. And a CMOS image sensor 34 for creating data. In addition, the LED illumination 2915, the reflector 36, and the polarizing element 24 are disposed at the upper base position of the frustum so as to be in parallel with the light receiving lens 31 and the CMOS image sensor 34.

  As described above, the LED illumination 2911 to the LED illumination 2914 emit light by using the upper side surface portion 231 to the right side surface portion 234 as a block and emit the blue LED diffused light IL from the side surface to the barcode. From 2915, red LED illumination IL is emitted in the barcode reading direction. The LED illumination IL from the LED illumination 2915 passes through the polarizing element 242 for light projection of the polarizing element 24, for example, is blocked except that it is vertically polarized and allows only the vertically polarized LED illumination light IL to pass through. The reflected light IL from the object is passed through the light receiving polarizing element 241 of the polarizing element 24, so that only the horizontally polarized LED illumination light IL is allowed to pass through, except for being horizontally polarized. For example, for a reading target that reflects light as it is like a mirror surface, the light-receiving polarizing element 241 is 90 ° out of phase with the light-projecting polarizing element 242 when receiving light and the light-projecting polarizing element 242 when receiving light. Thus, only the LED illumination light IL newly polarized between the two can be captured by the CMOS image sensor 34. Therefore, the LED illumination 2915 via the polarizing element 24 is effective illumination for a reading target that reflects near specular reflection.

  24 and 25 are schematic views showing the configuration of the diffusion plate 23, and show a view from the outside and a view from the inside, respectively. As described above, the diffusion plate 23 is milky white by mixing a transparent diffusion resin with a granular diffusion material. As shown in these drawings, the shape is substantially a truncated pyramid, and the upper base of the truncated pyramid is slightly inclined downward. An upper side surface portion 231 having an inclined side surface opened to the upper side of the head portion is formed above the pyramid surface of the quadrangular pyramid, and a lower side surface portion 233 substantially parallel to the imaging axis is formed below the same. It is formed below the imaging axis. In addition, a polarizing element window 243 for imaging and projecting light through the polarizing element 24 is provided on the upper base of the quadrangular pyramid. In this polarizing element window 243, a polarizing element 24 formed by processing the light receiving polarizing element 241 and the light projecting polarizing element 242 into a single sheet with a phase shift of exactly 90 ° is provided for the light receiving polarizing element 241. On the upper side, the light projecting polarizing element 242 is disposed on the lower side. The shape of the diffusing plate 23 is not limited to a quadrangular frustum shape, and may be, for example, a dome shape or a frustum shape such as a truncated cone and a truncated pyramid so that a side surface surrounds the imaging axis. Good. Further, the shape of the diffusing plate 23 may surround the imaging axis without any gap or may have a gap. That is, a plurality of side surfaces may be separated from each other.

  As described above, the transmittance of the diffusion plate 23 is increased. Therefore, it is necessary to prevent the diffused light transmitted through the diffusion plate 23 from being reflected internally and returning. Thereby, the reading performance can be further improved. For example, as shown in FIGS. 26A and 26B, the internal structure behind the diffusion plate 23 is preferably made of a material that absorbs light as much as possible. In the present embodiment, visible light is used for LED illumination. In this case, for example, a resin cast or black resin having a black color is used as a material constituting the interior behind the diffusion plate 23. preferable. Further, it is preferable to adopt a black color as much as possible for the harnesses. The light source used in the present invention is assumed to be LED illumination, but is not limited to one that emits visible light, and can be applied to one that emits electromagnetic waves widely including infrared rays. The internal structure is not limited to a black resin cast or black resin suitable for visible light.

  In this embodiment, it is assumed that the diffusion plate 23 is block-lit, and even in the same part, it is necessary to have both the role of the light emitting surface ES and the role of the opposing surface OS. Thus, in all the parts, the transmittance is uniformly set to 70% or more and 90% or less, and the transmittance is increased while maintaining the diffusion rate. On the other hand, for example, since the characteristics of the reading target are various, when a handy scanner specialized for the characteristics of the reading target is required, as another embodiment, as shown in FIG. 28, it faces the light emitting surface ES. There may be an embodiment in which only the transmittance of the portion corresponding to the facing surface OS is increased to 70% or more.

  Note that the contrast of the reading code (image) can be increased also in the case of polarized illumination by setting the facing surface OS to a transmittance of 70% or more. Specifically, when reading a white code with polarized illumination, the darker the opposed surface OS, the higher the contrast of the read code (image). Therefore, the reading performance can be improved by combining a light source such as the LED illumination 2915 and the facing surface OS having a transmittance of 70% or more.

  The present invention relates to a portable optical reader capable of preventing a decrease in contrast of image data obtained by an image pickup device and thus preventing a decrease in reading performance, and has industrial applicability.

DESCRIPTION OF SYMBOLS 1 ... Handy scanner 2 ... Grip part 3 ... Head part 4 ... Reading port 5 ... Battery 6 ... Battery cover 7 ... Battery cover lock 8 ... Protrusion 11 ... Charging unit connection part 12 ... Electrical contact 13 ... Engagement part 21 ... Indicator LED 211 ... Indicator driver 22 ... Indicator lens 23 ... Diffuser plate; 231 ... Upper side surface portion; 232 ... Left side surface portion; 233 ... Lower side surface portion; 234 ... Right side surface portion 24 ... Polarizing element; 241 ... Light receiving polarizing element; Polarizing element for light; 243 ... Window for polarizing element 25 ... Trigger switch 26 ... Trigger packing 27 ... Vibrator; 271 ... Motor driver 28 ... Reflecting plate 29 ... Illumination board; 2911-2915 ... LED illumination; 292 ... Driver 30 ... Camera cover 31 ... Photosensitive lens 32 ... Camera frame 33 ... Main substrate 34 ... CMOS image sensor 35 Battery charge controller 36 ... Reflector 37 ... Power supply board 41 ... Reading unit 42 ... Battery unit 43 ... Front case 44 ... Rear case 46 ... Light projecting unit 47 ... Light receiving unit 48 ... Operation unit 49 ... Notification unit 50 ... Function switch 51 ... Buzzer 511 ... buzzer driver 52 ... switch 53 ... battery terminal 101 ... charging unit IL ... illumination light

Claims (8)

An imaging unit that images a symbol to be read, a light source that emits light to the symbol imaged by the imaging unit, a diffusion member that diffuses light emitted from the light source, the imaging unit, the light source, and the A portable optical reader having a head unit that houses a diffusing member, and a gripping unit that is connected to the head unit and extends in the connecting direction and is gripped by a user,
The diffusion member is
A rear end surface disposed in front of the imaging unit in the head unit;
A first side surface that is connected to the rear end surface so as to surround the imaging axis of the imaging unit and that the light source is positioned outside the diffusing member, and sandwiches the imaging axis with the first side surface A side surface including the second side surface facing each other,
With
A portable optical reader, wherein the transmittance of the second side surface is 70% or more and the transmittance of the first side surface is 90% or less. The portable optical reader according to claim 1,
A plurality of the light sources are installed at intervals from each other so that only some of the blocks can be lit when the side surface of the diffusing member is divided into a plurality of blocks in the circumferential direction.
Among the plurality of blocks, a portable optical reading device in which one side surface of a pair of blocks facing each other with the imaging axis interposed therebetween is the first side surface, and the other side surface is the second side surface. The portable optical reader according to claim 1 or 2,
The diffusion member is formed in a substantially quadrangular pyramid shape,
The side surface
An upper side surface portion opened upward, which is the head portion direction of the grip portion,
A right side surface and a left side surface, which are connected to the upper side surface,
A lower side surface portion that is connected to the right side surface portion and the left side surface portion, and is positioned substantially parallel to the imaging axis and below the imaging axis;
A portable optical reader. The portable optical reader according to any one of claims 1 to 3,
A portable optical reader having a transmittance of 70% to 90% on all side surfaces of the diffusing member. The portable optical reader according to claim 3,
The relationship of the transmittance of the second side surface to the first side surface is at least the relationship of the transmittance of the left side surface portion to the right side surface portion, the relationship of the transmittance of the right side surface portion to the left side surface portion, and the lower side to the upper side surface portion. A portable optical reader that matches either the transmittance relationship of the side surface portion or the transmittance relationship of the upper side surface portion with respect to the lower side surface portion. The portable optical reader according to claim 5,
The relationship of the transmittance of the second side surface with respect to the first side surface is at least either the relationship of the transmittance of the lower side surface portion with respect to the upper side surface portion or the relationship of the transmittance of the upper side surface portion with respect to the lower side surface portion. A portable optical reader that matches one. The portable optical reader according to any one of claims 1 to 6,
The portable optical reader configured of a material that absorbs light so that the outer side of the second side surface absorbs diffused light that has passed through the first side surface. An imaging unit that images a symbol to be read, a light source that emits light to the symbol imaged by the imaging unit, a diffusion member that diffuses light emitted from the light source, the imaging unit, the light source, and the A portable optical reader having a head unit that houses a diffusing member, and a gripping unit that is connected to the head unit and extends in the connecting direction and is gripped by a user,
The diffusion member is
A rear end surface disposed in front of the imaging unit in the head unit;
A first side surface that is connected to the rear end surface so as to surround the imaging axis of the imaging unit, and is disposed so that the light source is located outside the diffusion member, and the first side surface and the imaging axis A side surface including a second side surface facing each other,
With
A portable optical reader, wherein the reflectance of the second side surface is less than 30% and the transmittance of the first side surface is 90% or less.