JP2010044469A - Reading unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a robust, and easy-to-manufacture optical reading apparatus, without need of user operation, enabling power saving. <P>SOLUTION: A reading unit for imaging a medium surface includes a light source for irradiating a medium surface with light, a lens for inputting reflective light from the medium surface, an imaging means for inputting the incident light via the lens, a control means for controlling the light source and the imaging means, and a first light guide body of a cylinder shape with a hollow, having an opening formed at the tip of the cylinder to be an entry of the reflective light from the medium surface, for irradiating the medium surface with light from the light source. The lens is disposed on the hollow of the first light guide body in such a manner as to face the opening of the first light guide body. The light source is disposed at an end portion of a slit provided inside the first light guide body. The irradiation light output from the light source travels inside the first light guide body, and from the opening, uniformly irradiates the medium surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical reading device (scanner) used for reading a two-dimensional code such as a dot pattern or a one-dimensional code such as a bar code.

  In recent years, one-dimensional codes such as barcodes and two-dimensional codes such as QR codes have been widely used as identifiers for recording various information such as voice and images. In particular, recently, a dot code (dot pattern) in which a plurality of dots as encoded information are arranged two-dimensionally has attracted attention. Since the dot code is read using a special scanner, it can be printed over a printed matter such as a photograph or a picture, so the appearance of the printed matter is not impaired and the area of the printed matter is not sacrificed. It is possible to print more information than the above.

  Such a one-dimensional code or two-dimensional code is read by a dedicated scanner. For example, when reading a dot code, light emitted from a pen-type scanner is applied to the printed surface on which the dot code is printed, and the reflected light is reflected from the part where the dot code is printed and the part where the dot code is not printed. The dot code is read according to the lightness and darkness and color difference.

  The LED provided in such a pen-type scanner has a very large variation in the irradiation direction, so when irradiating the dot code, the medium surface cannot be uniformly irradiated, and uneven illumination tends to occur. There was a problem that the dot code could not be read accurately. Further, in order to solve such a problem, there is a problem that the number of LEDs has to be increased, resulting in a significant increase in power consumption and cost.

  In order to solve such a problem, a code reader in which an illumination unit is unitized has been proposed (for example, Patent Document 1). In this code reader, a plurality of light sources such as LEDs, an illumination board on which the light sources are mounted, a light diffusion member for diffusing illumination light emitted from the light source, and diffused light diffused from the light diffusion member A light reflecting member that reflects toward the code pattern is integrally unitized.

  By unitizing in this way, it is possible to judge the quality of the illumination unit at the time of the unit, so that it is possible to prevent the occurrence of defective products due to unevenness in the amount of light in advance and provide a product that can accurately read the dot code. it can.

  In this document, a code reader is also proposed in which a diffusing portion is provided near the optical axis of the LED and a non-diffusing portion is provided at a position away from the optical axis. According to this, light with high intensity near the LED optical axis is diffused by the diffusion section and light emission intensity becomes weak, and light with low intensity away from the LED optical axis reaches the code pattern with almost no attenuation.

  Therefore, uniform illumination light with no illumination unevenness can be obtained without increasing the number of LEDs or the LED drive current, and a low-cost and power-saving code reader can be provided.

Japanese Patent Laid-Open No. 11-7490

  However, since the code reader of Patent Document 1 requires a plurality of LEDs, there is a limit in reducing power consumption. In addition, when using a code reader, it is necessary to operate a reading switch. Although such a switch has the advantage of requiring less power consumption than a structure in which the power is always supplied, the operation is troublesome. However, there are problems that the structure is complicated, the manufacturing cost is high, and it is further fragile.

  The present invention has been made in view of the above points, and it is a technology to provide an optical reading device that is robust without requiring user operation, can realize power saving, can be manufactured at low cost, and can be easily manufactured. As an objective.

  (1) In order to solve the above-described problem, a reading unit according to the present invention is a reading unit that images a medium surface, and a light source that irradiates light to the medium surface and reflected light from the medium surface. An incident lens, an imaging means for receiving incident light that has passed through the lens, a control means for controlling the light source and the imaging means, and a cylindrical shape having a hollow portion, and the tip from the medium surface A first light guide for irradiating the surface of the medium with light from the light source, in which an opening serving as an entrance for reflected light is formed, and the lens has an opening of the first light guide. The light source is disposed at the end of a slit provided in the first light guide so as to face the portion, and from the light source, the light source is disposed in the hollow portion of the first light guide. Is irradiated to the medium surface uniformly from the opening through the inside of the first light guide. To.

  (2) The reading unit according to the present invention is characterized in that light emitted from the light source is light of a predetermined wavelength.

  (3) The reading unit according to the present invention is characterized in that only one light source is disposed at an end of the slit provided in the first light guide.

  According to this, the light irradiated from the light source (LED) travels through the inside of the light guide, so that the irradiated light reaches the side where the light source is not provided. Therefore, it is not necessary to provide two light sources as in the prior art, and the medium surface can be imaged with only one light source, so that power consumption can be reduced.

  (4) A reading unit according to the present invention includes a second light guide that guides light from the light source reflected by a predetermined region on the medium surface to a predetermined position, and a predetermined light source disposed at the predetermined position. An optical switch that operates by detecting wavelength light is further provided, and the irradiation light travels while diffusing and refracting inside the first light guide and is irradiated to the medium surface from the opening, Reflected in the predetermined area of the medium surface, reaches the optical switch via the second light guide, is sensed by the optical switch, and the control means detects the irradiation light from the optical switch. Based on the above signal, at least the imaging means is operated.

  According to this, the control device operates the imaging device (C-MOS sensor or the like) only when weak irradiation light from the light guide flows. Therefore, power consumption can be greatly reduced compared to a conventional reading unit in which the image sensor is always operated.

  (5) The reading unit according to the present invention is characterized in that the second light guide has a hollow tubular shape at least on the side where the reflected light is incident on the predetermined region.

  (6) In the reading unit according to the present invention, the control unit images the power source in a power saving mode in which the light source is turned on by medium detection power only when the medium is detected, and the light source is continuously or the imaging unit is controlled to take an image. A normal mode that is lit by imaging power, and performs power saving control by switching between the power saving mode and the normal mode, at least the transition from the power saving mode to the normal mode is This is performed by a signal from an optical switch.

  According to this, since a light source can be made intermittent, power consumption can be reduced.

  (7) In the reading unit according to the present invention, in order to prevent light having a predetermined wavelength from entering the second light guide into the outer peripheral portion excluding at least an end section of the second light guide. A light blocking layer having a predetermined wavelength is provided.

  According to this, it is possible to prevent unnecessary light having a predetermined wavelength from entering from the outside and allow only a necessary light source to pass through the light guide.

  (8) The reading unit according to the present invention is characterized in that the predetermined wavelength light blocking layer is a predetermined wavelength light reflecting layer or a predetermined wavelength light absorbing layer.

  (9) In the reading unit according to the present invention, the predetermined wavelength light blocking layer has the reflected light in the predetermined region incident on the second light guide and reflected by a peripheral wall inside the light guide. It is a light reflection layer having a predetermined wavelength for the purpose.

  (10) In the reading unit according to the present invention, at least an inner peripheral surface in the vicinity of an end portion on the medium surface side of the tubular portion having a hollow of the second light guide is from the predetermined region of the medium surface. The reflected light is guided from the first light guide so that only reflected light enters and travels through the second light guide, and at least near the medium surface on the end extension of the second light guide. A predetermined wavelength light absorption layer is provided in a predetermined region in order to absorb all of the predetermined wavelength light except the reflected reflected light.

  According to this, it is possible to prevent the detection range of the medium surface from expanding due to light of a predetermined wavelength reflected by the inner wall of the light guide.

  In addition, if both the predetermined wavelength light blocking layer and the predetermined wavelength light absorbing layer are provided, it is possible to read the medium surface in the most appropriate detection range at the same time as preventing the entry of unnecessary infrared light from the outside. The media surface can be read efficiently with less power.

  (11) The reading unit according to the present invention is characterized in that a protective filter for dust and / or waterproofing is provided in the vicinity of the opening of the first light guide.

  According to this, it is possible to prevent dust from entering the reading unit.

  (12) In the reading unit according to the present invention, the filter is a predetermined wavelength light transmission filter that transmits only the predetermined wavelength light of the light that enters the opening of the light source and / or the first light guide. It is characterized by that.

  According to this, it is not necessary to dispose a predetermined wavelength optical filter at the tip of the image sensor, so that the structure of the reading unit can be simplified.

  (13) The predetermined wavelength is an infrared ray.

  (14) In the reading unit according to the present invention, the information read by photographing the medium surface is such that a dot code composed of a code value and / or a coordinate value formed on the medium surface is patterned based on a predetermined algorithm. The dot pattern is optically readable.

  According to this, the light irradiated from the light source (LED) travels through the inside of the light guide, so that the irradiated light reaches the side where the light source is not provided. Therefore, it is not necessary to provide two light sources as in the prior art, and the dot pattern on the medium surface can be photographed with only one light source, so that power consumption can be reduced.

  According to the present invention, it is possible to easily and inexpensively provide a code reading unit that consumes significantly less power than conventional ones.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Overview>
FIG. 3 is an explanatory diagram showing an example of how the optical scanner according to the present invention is used.

  A series of flows will be described with reference to FIG.

  First, the optical scanner is used by being connected to a computer or the like. The medium is a printed matter such as paper on which characters or pictures are printed. On this medium, a dot pattern, which will be described later, is superimposed and printed with characters, pictures, and the like. When a user touches a character or picture on a medium using an optical scanner, a dot pattern superimposed on the touched letter or picture is read. The read dot pattern is image-analyzed by the CPU on the optical scanner and converted into a code value and / or coordinate value corresponding to the dot pattern. Code values and / or coordinate values are transmitted from the optical scanner to the computer. The control unit of the computer outputs an image, video, audio, or the like associated with the received code value and / or coordinate value to a display or the like connected to the computer. Note that the image analysis processing may be performed by a CPU on the optical scanner, or may be performed by a CPU on a computer to which the optical scanner is connected.

  The optical scanner may be connected to a device other than the computer or used in an integrated state with the device. 4 to 7 illustrate specific examples thereof. FIG. 4 shows an optical scanner connected to a stand-alone type voice recorder. In this embodiment, a dot pattern is superimposed and printed on a photograph. When a photograph is touched with an optical scanner, a dot pattern is read, and sound corresponding to the photograph is emitted from a speaker of a voice recorder.

  FIG. 5 shows a unit (speaking pen) in which a scanner and an audio reproduction device are integrated. When a character or picture on the medium is touched by the scanner unit of this apparatus, a dot pattern superimposed on the letter or picture is read, and sound corresponding to the contents of the letter or picture is emitted from the speaker.

  FIG. 6 shows a remote control device in which a scanner and a remote control are integrated. This remote control device is used for operation of a television or a set top box together with a paper controller. On the paper controller, icons representing operation instructions such as “power” and “volume” are printed, and a dot pattern is superimposed and printed on the icons. When an icon is touched on the scanner unit of the remote control device, the dot pattern is read, and an infrared signal corresponding to the dot pattern is emitted from the infrared light emitting unit to the infrared light receiving unit of the set top box. Then, the set top box performs processing corresponding to the infrared signal, that is, processing indicated by the icon of the paper controller.

  FIG. 7 shows a mobile phone connected with a scanner. On the paper controller, a picture or character (not shown) for instructing an operation is printed, and a dot pattern is superimposed and printed on the picture or character. When a picture or character is touched with the scanner, a dot pattern is read, and operations (transmission, mail reception, etc.) corresponding to the picture or character are performed.

  Note that examples of use of the optical scanner according to the present invention are not limited to those described above, and it is needless to say that the optical scanner can be used by being connected to various devices or integrally formed.

  FIG. 1 is an enlarged view showing an internal structure of a reading unit which is a tip portion of an optical scanner according to the present invention. The front end of the scanner is mounted on an optical scanner (a pen-type dot pattern reader main body) (not shown), and reads a dot pattern formed on a medium surface such as a printed material.

  The reading unit includes, as operation modes, a normal mode for reading and analyzing a dot pattern and a power saving mode for suppressing power consumption during standby. Details of the operation of each member of the reading unit in each mode will be described later.

  The front end of the scanner has a cylindrical shape having a hollow portion, and an opening is formed at the front end. The scanner includes a light guide (first light guide), and the light guide is hollow so as to face the opening of the light guide. A lens is arranged in the part. An IR filter and a C-MOS sensor (imaging means) are provided at a position retracted from the lens.

  The LED as the light source is provided at the end of the slit formed in the light guide. The LED preferably emits infrared rays, but is not limited to this frequency band. For example, a light source that emits ultraviolet rays may be used. However, when ultraviolet rays are used, a UV filter is used in place of the IR filter, and the dot pattern printed on the medium surface is also separated from the printed information other than the dot pattern in the ultraviolet region by using the ink on the medium surface. Need to be printed on top. In addition, since the light emission control of LED is an important point in the power saving mechanism according to the present invention, details will be described later.

  A light guide tube (second light guide) is provided inside the light guide opposite to the side where the slits are provided. By providing the light guide tube on the slit, that is, on the side opposite to the LED, it is possible to minimize interference by the light guide tube with respect to light irradiated from the LED to the medium surface through the opening.

  A printed wiring board (PCB) is mounted on the top of the tip, and an infrared switch (optical switch) that performs reflected light measurement for controlling the lighting of the LED and a detection from the infrared switch are mounted on the PCB. A small CPU (control means) with low power consumption that controls light emission of LEDs based on signals, and a large CPU (control means) for controlling the C-MOS sensor and analyzing the image read by the C-MOS sensor And are provided.

  A filter made of a transparent glass plate or a transparent plastic plate is attached to the opening. The filter closes the opening portion to prevent dust and the like from entering the internal space such as the hollow portion, and also has a role as an IR filter that transmits infrared rays from the LED. Therefore, when this filter is attached, the above-described IR filter may not be provided.

  The light guide is made of transparent or milky white resin, and the inside functions as a light guide. Irradiation light from the LED travels inside the light guide and is irradiated to the medium surface from the opening. When the light guide is made of milky white resin, the light emitted from the LED is appropriately diffused as it travels through the light guide, so that the light that irradiates the medium surface from the opening can be made more uniform. I can do it.

  A light reflecting layer is provided on the outer periphery of the light guide. The light reflecting layer is formed by coating with a material that reflects infrared rays.

  In this way, by providing a light reflection layer on the outer periphery of the light guide with a coating or the like, it is possible to efficiently irradiate the medium surface by preventing the divergence of the irradiated light to the outside, and by controlling the LED to an appropriate issue amount, It is also effective for power saving. In addition, the strength of the light guide can be improved. If the same strength is maintained, the strength required for the light guide itself can be reduced. In addition, the outer periphery of the light guide can be protected from scratches and wear without using a cap or cover that covers the light guide.

  Further, as described above, the light guide tube is provided on the side of the light guide where the LED is not provided. The light guide tube may be a tube formed of a material that transmits light, such as an optical fiber, or a tube having a hollow inside. The light guide tube guides the light reflected from a specific region among the reflected light of the light irradiated from the LED to the medium surface to the infrared switch. When detecting the irradiation light guided by the light guide tube, the infrared switch transmits a detection signal to the large CPU. The large CPU activates and operates the C-MOS sensor (imaging means) based on the sensing signal from the infrared switch. A C-MOS sensor activated by a large CPU captures reflected light reflected on the medium surface from the LED, and analyzes the captured image to read a dot pattern.

  In the normal mode, the constituent members at the tip of the scanner involved in the operation are a large CPU, an LED, a light guide, a lens, an IR filter, and a C-MOS sensor.

  When the large CPU recognizes that the medium surface has been touched by the user, in the normal mode, first, the large CPU causes the LED to emit light in order to read the dot pattern on the medium surface applied to the opening of the reading unit. . When the LED illuminates the medium surface via the light guide, the reflected light enters the lens, and the C-MOS sensor images the reflected light.

  Information is read from the dot pattern on the medium surface by analyzing the image taken by the C-MOS sensor.

  After the analysis of the captured image ends, the large CPU returns to the process of capturing an image with the C-MOS sensor again.

  The LED may be always lit during the normal mode, or may be lit only during image capturing by the C-MOS sensor. In a configuration in which the light is turned on only during image shooting, power consumption can be reduced.

  The large CPU determines that the user is not using the reading unit when the brightness of the image shooting result is below a predetermined amount, indicating that the medium surface does not touch the opening of the reading unit. Transition from mode to power saving mode.

  In the transition to the power saving mode, first, the small CPU is activated, and after confirming the activation, the large CPU suspends its operation and suppresses power consumption.

  Here, the dot pattern on the medium surface is printed with carbon ink or stealth ink (invisible ink) that absorbs infrared rays.

  Portions other than the dot pattern are printed with an ink such as non-carbon ink having a characteristic of reflecting or transmitting infrared rays. When transmissive ink is used, the transmitted infrared light is reflected by the medium surface, passes through the ink again, and is imaged by the C-MOS sensor.

  Since this carbon ink and stealth ink (invisible ink) have the characteristic of absorbing infrared rays, in the image picked up by the C-MOS sensor, the reflected light cannot be obtained only at the dot portion, so the black ink is taken. become.

  FIG. 2 is a hardware block diagram illustrating the configuration of the front end of the scanner involved in the power saving mode.

  As shown in the figure, in the power saving mode, the components at the tip of the scanner involved in the operation are a large CPU, a small CPU, an infrared switch, an LED, a light guide, and a light guide tube. .

  The operation of each member in the power saving mode is as follows.

  First, the large CPU detects that the scanner is not used for reading based on the image analysis result in the normal mode.

  The large CPU determines that the scanner is not being used, activates the small CPU to switch the reading unit from the normal mode to the power saving mode, and after confirming the activation of the small CPU, the large CPU stops operating. Reduce power consumption.

  Next, the small CPU that has taken over the control in the power saving mode causes the LED to emit light at a preset time interval. The amount of emitted light may be an amount that can detect light reflected from the medium surface irradiated through the light guide when the pen surface is used again and the medium surface is applied to the opening of the reading unit. Therefore, as compared with the case where the medium surface is captured and analyzed as an image, the intermittent lighting time may be short, and only a small amount of light needs to be emitted, so that power consumption can be suppressed.

  When the LED emits light and the medium surface does not hit the opening, the light from the LED is not reflected by the medium surface, so that there is no reflected light reaching the infrared switch via the light guide tube. Therefore, no sensing signal is transmitted from the infrared switch to the small CPU. When the sensing signal is not received, the small CPU waits until the predetermined time elapses and the LED emits light.

    When the medium surface hits the opening when the LED emits light, the light from the LED is reflected by the medium surface, so that the reflected light reaches the infrared switch via the light guide tube. The infrared switch senses the reflected light that has arrived and transmits a sensing signal to the small CPU. When the sensing signal is received, the small CPU determines that the use of the scanner has been resumed, and activates the large CPU to switch the reading unit from the power saving mode to the normal mode. Since the small CPU operates with low power, it does not affect power consumption even if it operates constantly.

  When returning to the normal mode, the large CPU activates the C-MOS sensor, which is an optical imaging device, and images the reflected light from the medium surface of the light emitted from the LED onto the medium surface.

  Further, the large CPU returns the light emission control of the LED to the control suitable for the normal mode. For example, the LED may be turned on constantly, or may be turned on intermittently so as to stop the emission of the LED while analyzing the captured image, or at a predetermined interval within a range that does not hinder the use of the scanner. It may be turned on intermittently.

<Advantages of configurations without moving parts>
Conventionally, a physical switch such as a slide switch or a push switch has been used to activate the reading unit or to return from the power saving mode to the normal mode. However, the physical switch has a problem that the operation is troublesome, the structure is complicated and the manufacturing cost is high, and it is further fragile. Therefore, in the present invention, by adopting a configuration that returns to the normal mode by detecting reflected light, it is possible to realize a reading unit having a simple structure and a switch that is not easily broken and that does not require user operation.

<About dot pattern>
A dot pattern is printed on the medium surface. As described above, the dot pattern is printed with carbon ink or stealth ink (invisible ink), and portions other than the dot pattern are printed with ink having a characteristic of reflecting or transmitting infrared rays, such as non-carbon ink. When transmissive ink is used, the transmitted infrared light is reflected by the medium surface, passes through the ink again, and is imaged by the optical imaging element.

  Since the carbon ink and the stealth ink (invisible ink) have a characteristic of absorbing infrared rays, in the image picked up by the optical image pickup device, the reflected light cannot be obtained only in the dot portion, so that the black ink is taken. Become.

  Here, the irradiation light has been described in the present embodiment in the case where a dot pattern printed with carbon ink and stealth ink (invisible ink) using infrared rays is used. However, the dot pattern may be printed using, for example, an ultraviolet ray or a light beam having a specific frequency, and an ink having a characteristic of absorbing the ultraviolet ray or a characteristic of changing the optical characteristic.

  The captured image of the dot pattern read in this way is transmitted to the large CPU, and the large CPU converts it into a code value and / or coordinate value by a dot pattern analysis program.

  Such a dot pattern will be described with reference to FIGS.

  In these drawings, vertical and horizontal grid lines are provided for convenience of explanation, and are not present on the actual print surface. The key dots 102, the reference grid dots 103, the information dots 104, and the like that constitute the dot pattern 101 are carbon ink or stealth ink (invisible ink) that absorbs infrared rays when the scanner as an imaging means has infrared irradiation means. ) Is desirable.

  FIG. 12 is an enlarged view showing an example of the arrangement of the key dots 102, the reference grid point dots 103, and the information dots 104 of the dot pattern 101. FIGS. 13A and 13B are explanatory diagrams showing information dots 104 representing vector information and encoding.

  An information input / output method using a dot pattern includes generation of a dot pattern 101, recognition of the dot pattern 101, and analysis of the dot pattern 101 to output information and a program. That is, the dot pattern 101 is captured as image data by the sensor unit 3, and based on the program read by the CPU, first, the reference grid point dot 103 is extracted, and then the dot is located at the position where the reference grid point dot 103 should originally exist. Key dots 102 are extracted when dots are arranged at positions shifted in a predetermined direction without being arranged, and a dot pattern 101 for one block and its direction are specified. Next, information dots 104 surrounded by four reference grid point dots 103 or key dots 102 are extracted and encoded by a predetermined algorithm, and the information dots 104 are arranged according to the arrangement of the information dots 104 in the dot pattern 101 for one block. Are decoded into a predetermined code value and / or coordinate value, and the code value and / or coordinate value is output as information, a program such as a sound, an image, and a moving image.

  The dot pattern 101 is generated by using a dot code generation algorithm to make fine dots, that is, at least one key dot 102, a reference grid point dot 103, and an information dot 104 in order to recognize vector information for encoding. Arrange according to a predetermined rule. As shown in FIG. 12, in the block of the dot pattern 101, 5 × 5 reference grid point dots 103 are arranged, and around the four reference grid point dots 103 or the virtual center point 105 surrounded by the reference grid points. Information dots 104 representing vector information are arranged. The arrangement / configuration of blocks is determined by the key dots 102. In the case of this embodiment, the key dot 102 is a dot that is not arranged on a reference grid point at one corner of the block but is shifted in a predetermined direction from the dot, and the size of the block is determined. In addition, the direction of the block, that is, the dot pattern 101 is defined. Arbitrary numerical information is defined in this block. The illustrated example of FIG. 12 shows a state in which four blocks (inside the bold line frame) of the dot pattern 101 are arranged in parallel. Of course, the dot pattern 101 is not limited to four blocks.

  The key dots 102 are not limited to the corners of the block, and may be arranged at any position inside or outside the block.

  When the dot pattern 101 is captured as image data by the sensor unit, the dot code analysis algorithm uses the lens distortion of the sensor unit, imaging from an oblique direction, expansion and contraction of the paper surface, curvature of the medium surface, reference grid point dots at the time of printing The distortion of the arrangement 103 can be corrected. Specifically, a correction function (Xn, Yn) = f (Xn ′, Yn ′) for converting the distorted four reference grid point dots 103 into the original square or rectangle is obtained, and information is obtained using the same function. The dot 104 is corrected, and vector information is obtained from the correct position of the information dot 104.

  The information dot 104 is a dot for recognizing various vector information. The information dot 104 is arranged in the dot pattern 101 for one block constituted by the key dots 102, and is a virtual center point 105 surrounded by four reference grid point dots 103. It is arranged at the end point expressed by. For example, the information dot 104 is surrounded by four reference grid points 103 or reference grid points, and the dots away from the virtual center point 105 are represented by vectors as shown in FIG. In order to have a direction and a length, it is rotated 45 degrees clockwise, arranged in 8 directions, and encoded into 3 bits. Therefore, 3 bits × 16 pieces = 48 bits can be expressed by one block of dot pattern 101.

  FIG. 13B is a method of encoding 2 bits for each information dot 104 in the dot pattern 101 of FIG. 8. The dots are shifted in the + direction and the X direction and encoded into 2 bits. 2 bits × 16 pieces = 32 bits are expressed. Thus, although 48-bit numerical information can be originally defined by the dot pattern 101 for one block, the numerical information can be given every 32 bits by being divided according to use. A maximum of 216 (about 65000) information dot arrangement patterns can be realized by combining the + direction and the X direction.

  However, the present invention is not limited to this, and it is possible to encode 4 bits by arranging in 16 directions, and of course, it is possible to change the encoding by arranging in various directions.

  The dot diameters of the key dot 102, the reference grid dot 103, and the information dot 104 are 0.03 to 0.05 mm in consideration of appearance, paper quality, printing accuracy, resolution of the sensor unit 3, and optimum digitization. It is desirable to be in the range of about.

  In addition, considering the amount of information required for the imaging area and misidentification of the various dots 102, 103, 104, the interval between the reference grid point dots 103 must be in the range of about 0.3 to 0.5 mm both vertically and horizontally. Is desirable. In consideration of misidentification with the reference grid point dot 103 and the information dot 104, the shift of the key dot 102 is preferably about 20% of the grid interval.

  The distance between the information dot 104 and the virtual center point 105 surrounded by the four reference grid point dots 103 is about 15 to 30% of the distance between the adjacent reference grid point dot 103 and the virtual center point 105. It is desirable that This is because if the distance between the information dot 104 and the virtual center point 105 is larger than this distance, the reference grid point dot 103 and the information dot 104 are easily recognized as a lump, and the dot pattern 101 looks unsightly as a pattern. On the contrary, if the distance between the information dot 104 and the virtual center point 105 is smaller than this distance, it is difficult to recognize in which direction the information dot 104 having vector information centered on the virtual center point 105 is located. Because it becomes.

  As shown in FIG. 12, one dot pattern 101 is a dot pattern 101 composed of 4 × 4 block areas, and 2-bit information dots 104 are arranged in each block. FIG. 12 shows the dot code format of the dot pattern 101 for one block constituting the set of information dots 104.

  As shown in FIG. 16A, in one dot pattern 101, a parity check and a code value are recorded. In (b), a parity check, a code value, and an XY coordinate value are recorded. The dot code format can be arbitrarily determined.

  FIG. 14 is an example showing information dots 104 having vector information and other forms of encoding. As shown in this example, if two types of information dots 104, the long and short, are used from the reference grid point dot 103 or the virtual center point 105 surrounded by the reference grid points, and the vector direction is 8 directions, 4 bits are encoded. Can be At this time, it is desirable that the longer one is about 25-30% of the distance between adjacent virtual center points 105, and the shorter one is about 15-20%. However, it is desirable that the center interval between the long and short information dots 104 is longer than the diameter of these information dots 104 so as not to be mistaken.

  If there are a plurality of four reference grid dots 103 or information dots 104 surrounded by the reference grid points, adjacent dots are easily seen as a lump, and a pattern is generated. Therefore, one dot is desirable in consideration of appearance. However, when it is desired to ignore the appearance and increase the amount of information, it is possible to have a large amount of information by encoding one bit for each vector and expressing the information dot 104 with a plurality of dots. For example, in 8 vectors in 8 directions of concentric circles, 4 reference grid point dots 103 or 8 information dots 104 surrounded by the reference grid points can be encoded in 8 bits, and 16 bits in the direction of concentric double circles 8 can be encoded. In the vector, 0 to 16 information dots 104 of one block can be encoded and 16 bits can be encoded.

  FIG. 15 is an example of 16 vector information dots 104 in the direction of concentric double circles 8 and encoding. (A) shows two information dots 104, (b) shows four information dots 104, and (c). Indicates an arrangement of five information dots 104.

  FIG. 17 shows a modified example of the dot pattern 101. FIG. 17A shows an arrangement type of four reference grid point dots 103 surrounding the information dots 104 or six square or rectangular areas composed of the reference grid points. ) Is a schematic view of 9 arrangement types, (c) is a 12 arrangement type, and (d) is a 36 arrangement type.

  A dot pattern 101 shown in FIG. 12 shows an example in which 16 (4 × 4) information dots 104 are arranged in one block. However, the number of information dots 104 is not limited to 16 arranged in one block, but as shown in FIGS. 15 and 17, four reference grid dots 103 or an area composed of reference grid points surrounding the information dots 104 , And the encoding of the information dot 104 defined in the area can be variously changed.

  Of course, the dot pattern read by the scanner according to the present invention is not limited to the above-described dot pattern, and may be a dot pattern generated by another algorithm.

  FIG. 8 is a flowchart for explaining the operation of the reading unit reading the dot pattern. In the present invention, since the switch for returning from the power saving mode to the normal mode is one of the points, this flowchart is described on the assumption that the reading unit is currently in the power saving mode. .

  First, the small CPU stands by for a predetermined time. A small current flows through the small CPU and is in a state of waiting for light emission of the LED (step 31, hereinafter abbreviated as S31).

  Next, after a predetermined time has elapsed, the small CPU causes the LED to emit light using power sufficient to ensure the light emission amount necessary for detecting the medium surface (S32).

  Next, the small CPU determines whether or not the emitted light is reflected by the medium surface applied to the opening of the reading unit, and the reflected light is detected by the optical switch via the light guide tube (S33). .

  If it is determined that it has not been detected, the process returns to S31.

  If it is determined that it has been detected, the process proceeds to S34.

  When determining that it has been detected, the small CPU returns the reading unit to the normal mode. In the normal mode, the large CPU and the C-MOS camera are activated, and the control is transferred from the small CPU to the large CPU. Further, the LED emits light using the power for photographing an image (S34).

  Next, the large CPU captures the reflected light from the opening using the C-MOS sensor, and performs image processing for analysis of the captured image (S35). The light from the LED irradiates the surface of the medium applied to the opening, and the C-MOS sensor images the reflected light.

  Next, the large CPU determines whether or not the photographed image is dark (S36). If the image is dark, it is determined that the medium surface is not applied to the opening of the reading unit, that is, the reading unit is not used by the user. If the image is not dark, the dot pattern on the medium surface is read, analyzed, and converted to a dot code (S37).

  Next, the large CPU shifts to the power saving mode (S38). When the reading unit completes the transition to the power saving mode, the reading unit returns to the process of S31.

  FIG. 9 is a diagram showing the light guide of the reading unit from the axial direction and the top surface thereof. The center of the light guide is a hollow portion, and a groove is formed on the left side. A light guide tube is installed in this groove. A slit is formed on the right side of the light guide, and an LED is installed inside the slit.

  10-11 is explanatory drawing shown about the structure of the light guide tube used by this invention.

  As described above, the light guide tube is formed of, for example, an optical fiber or a hollow material, and guides the light reflected from the medium surface of the irradiation light from the LED to the infrared switch. The shape is a linear shape or a curved shape. Further, the cross section of the light guide tube may be a circle, an ellipse or a polygon.

  FIG. 10A is a diagram illustrating a linear light guide tube. In the figure, for example, the inside is a cavity and the surrounding is made of an infrared absorbing material, so that reflection does not occur on the inner wall. Therefore, only light directly incident on the infrared switch, that is, light reflected in a narrow range is detected. Thereby, it is possible to prevent the light guided to the light guide from directly entering the light guide tube without being reflected by the medium surface. In addition, an infrared reflection layer is provided outside the light guide tube to block infrared rays from the outside.

  If the inside of the light guide is not hollow, the reflected light from the medium surface is refracted at a critical angle.

  FIG. 4B is a diagram for explaining a curved light guide tube. In the case of a curved shape, the reflected light from the medium surface reaches the infrared switch while being reflected by the inner wall. An infrared ray reflection layer is provided outside the light guide tube to block infrared rays from the outside.

  As shown in the figure, in the case of a curved line and a straight line, when total reflection occurs at a critical angle due to the inner wall of the tube, reflected light from a wider range can be guided to the infrared switch.

  FIG. 11 is an explanatory diagram showing the structure of the tip of the curved light guide tube.

  At the tip of the curved light guide tube, the detection range of the medium surface to be read is widened by total reflection of infrared rays on the inner wall as shown in FIG. Therefore, when reading the reflected light from a narrow range, as shown in FIG. 5A, if the inner peripheral surface of the tip is a hollow tube (infrared absorbing layer) having an inner wall (carbon) that absorbs infrared rays. The detection range can be narrowed. That is, a spot that is incident at an angle and does not enter the region that directly absorbs infrared rays can be absorbed to narrow the spot. By narrowing down the spot, the light directly entering from the light guide is reflected inside the light guide tube so that it cannot reach the infrared switch.

  The length of the tube on which the infrared absorbing layer is provided is determined from the area of the reflecting surface necessary for obtaining the light amount necessary to activate the infrared switch.

  In addition, when using reflection at a critical angle other than the tip, the outer wall of the light guide tube may be carbon. To prevent light from escaping, the outer wall of the light guide tube is made of an infrared reflecting material.

  In the case of FIG. 12B, since the critical angle is exceeded, the reflected light comes out of the light guide tube. Therefore, in such a case, if an infrared reflecting material is coated inside the light guide tube, the reflected light can reach the infrared switch without leaking outside.

  In addition, in either case of using an optical fiber or a hollow material, it is necessary to coat the outside of the light guide tube to block infrared rays. This is to prevent the intrusion of infrared rays existing outside the light guide tube. The coating is performed with a material that reflects infrared rays or a material that absorbs infrared rays. When a coating that reflects infrared light is used, the reflected light reaches the infrared switch while being reflected at any angle. Even if the flow exceeds the critical angle, a lot of light reaches the switch. On the other hand, when a coating that absorbs infrared rays is used, the reflected light inside the light guide tube does not reach the infrared switch unless it is below the critical angle.

  In addition, when the light guide tube is formed using the hollow material, the entire light guide tube is made of the hollow material, and only the end portion on the side where the reflected light is incident is made of the hollow material, and the other parts. May be formed using an optical fiber.

  In the above-described embodiment, the reading unit for reading the medium surface on which the dot pattern is formed has been described as a representative example. However, the present invention is not limited to this, and the code printed on the medium surface is Another two-dimensional code such as a QR code or a one-dimensional code such as a barcode may be used. Further, it may be print information such as characters, figures, symbols and the like.

<Other Embodiments of Power Saving Mechanism>
Next, another embodiment of the power saving mechanism in the reading unit according to the present invention will be described.

  In conventional optical scanners, the dot pattern on the medium surface is controlled to be accurately imaged by controlling the aperture of the CMOS sensor and adjusting the amount of light at the time of imaging. That is, if the captured image of the frame buffer is too bright, the aperture is reduced to reduce the amount of light, and if it is too dark, the aperture is opened to increase the amount of light.

  On the other hand, the reading unit according to the present invention does not perform dynamic control of the diaphragm, and uses a fixed value for the diaphragm. This is because the reading unit according to the present invention is used for the purpose of reading by placing the reading unit against the medium surface, so that an aperture is set in advance so that the exposure can be performed under the optimum exposure condition when the medium is brought into contact with the medium surface. Because it is.

  In the reading unit according to the present invention, the analysis time for the read dot pattern can be shortened by the amount of time required for dynamically controlling the aperture.

  Further, since power is consumed for dynamic control of the diaphragm, power consumption can be reduced by not performing dynamic control of the diaphragm, and a power-saving reading unit can be provided.

  The present invention can be used for a code reader used for reading a two-dimensional code such as a bar code or a dot code.

FIG. 3 is an enlarged view showing an internal structure of a reading unit which is a tip portion of the optical scanner according to the present invention. It is a hardware block diagram explaining the structure of the front-end | tip part of a scanner. It is explanatory drawing (1) which showed the example of the use condition how the optical scanner which concerns on this invention is used. It is explanatory drawing (2) which showed the example of the use condition how the optical scanner which concerns on this invention is used. It is explanatory drawing (3) which showed the example of the use condition how the optical scanner which concerns on this invention is used. It is explanatory drawing (4) which showed the example of the use condition how the optical scanner which concerns on this invention is used. It is explanatory drawing (5) which showed the example of the use condition how the optical scanner which concerns on this invention is used. It is the flowchart explaining the operation | movement which a reading unit reads a dot pattern. It is the figure which showed the light guide of the reading unit from the axial direction and the upper surface. It is explanatory drawing about a light guide tube, (a) is a linear light guide tube, (b) is a figure explaining the curved light guide tube. It is explanatory drawing shown about the structure of the front-end | tip part of a curved-shaped light guide tube. It is a figure (1) explaining GRID1 which is an example of a dot pattern. It is FIG. (2) explaining GRID1 which is an example of a dot pattern. FIG. 5C is a diagram (3) illustrating GRID1 that is an example of a dot pattern. It is FIG. (4) explaining GRID1 which is an example of a dot pattern. It is FIG. (5) explaining GRID1 which is an example of a dot pattern. It is FIG. (6) explaining GRID1 which is an example of a dot pattern.

Explanation of symbols

101 Dot pattern 102 Key dot 103 Reference grid dot 104 Information dot

Claims (14)

A reading unit for photographing a medium surface,
A light source for irradiating the medium surface with light;
A lens for incident light reflected from the medium surface;
Imaging means for receiving incident light that has passed through the lens;
Control means for controlling the light source and the imaging means;
A cylindrical shape having a hollow portion, an opening serving as an entrance of the reflected light from the medium surface is formed at the tip thereof, for diffusing and refracting light from the light source to irradiate the medium surface A first light guide;
The lens is disposed in the hollow portion of the first light guide so as to face the opening of the first light guide,
The light source is disposed at an end of a slit provided inside the first light guide,
Irradiation light from the light source travels while diffusing and refracting inside the first light guide, and is uniformly irradiated to the medium surface from the opening.   The reading unit according to claim 1, wherein the light emitted from the light source is light having a predetermined wavelength.   The reading unit according to claim 1, wherein only one light source is disposed at an end of the slit provided in the first light guide. A second light guide for guiding light from the light source reflected by a predetermined region on the medium surface to a predetermined position;
An optical switch that is disposed at the predetermined position and operates by detecting light of a predetermined wavelength;
The irradiation light is
After diffusing and refracting inside the first light guide and irradiating the medium surface from the opening,
Reflected at the predetermined area of the medium surface;
Reaching the optical switch via the second light guide;
Sensed by the optical switch;
The control means includes
Based on the signal from the optical switch that senses the illumination light,
The reading unit according to claim 1, wherein at least an imaging unit is operated.   The reading unit according to claim 4, wherein the second light guide has a hollow tubular shape at least at an end portion on the side where the reflected light is incident in the predetermined region. The control means includes
A power saving mode in which the light source is turned on by medium detection power only during medium detection;
A normal mode in which the light source is turned on continuously or when the imaging means is controlled to take an image,
Perform power saving control by switching between the power saving mode and the normal mode,
6. The reading unit according to claim 4, wherein at least the transition from the power saving mode to the normal mode is performed by a signal from the optical switch.   A predetermined wavelength light blocking layer is provided on an outer peripheral portion excluding at least an end section of the second light guide so as to prevent light having a predetermined wavelength from entering the second light guide. The reading unit according to claim 4 or 5.   The reading unit according to claim 7, wherein the predetermined wavelength light blocking layer is a predetermined wavelength light reflecting layer or a predetermined wavelength light absorbing layer.   The predetermined wavelength light blocking layer is a predetermined wavelength light reflecting layer for allowing reflected light in the predetermined region to enter the second light guide and to be reflected and travel within the peripheral wall of the light guide. The reading unit according to claim 7. At least an inner peripheral surface in the vicinity of the end on the medium surface side of the tubular portion having a hollow portion of the second light guide, only the reflected light from the predetermined region of the medium surface is the second light guide. All light of a predetermined wavelength except reflected light that is guided from the first light guide and reflected at least near the medium surface on the end extension of the second light guide. The reading unit according to claim 4, wherein a light absorption layer having a predetermined wavelength is provided in a predetermined region in order to absorb light.
  The reading unit according to any one of claims 1 to 10, wherein a protective filter for dustproof and / or waterproofing is provided in the vicinity of the opening of the first light guide.   The said filter is a predetermined wavelength light transmission filter which permeate | transmits only the predetermined wavelength light of the light which injects into the opening part of the said light source and / or the said 1st light guide. Reading unit.   The reading unit according to claim 2, wherein the predetermined wavelength is infrared rays.   The information read by photographing the medium surface is an optically readable dot pattern in which a dot code composed of code values and / or coordinate values formed on the medium surface is patterned based on a predetermined algorithm. The reading unit according to claim 1.

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