JP4107280B2 - Image sensor and information code reader - Google Patents

Description

  The present invention has an image sensor having a plurality of pixels arranged in a matrix and storing charges corresponding to the amount of incident light, and having a function of outputting signals sequentially read from the plurality of pixels in a predetermined cycle time. The present invention also relates to an information code reader provided with the image sensor.

  An information code reader, such as a barcode reader or a two-dimensional code reader, has a function of reading a one-dimensional code (for example, a barcode) or a two-dimensional code (for example, a QR code) that is an information code printed on paper or a product. is doing. Recent barcode readers are equipped with a one-dimensional sensor having about 2000 to 3600 pixels, and are configured to be able to read a barcode far from the barcode reader or a barcode with a small minimum bar width. Yes.

  In recent years, for example, a QR code reader, which is a two-dimensional code reader, includes an image sensor (area sensor) having about 1.3 million pixels, and is configured to read each cell of the QR code by the image sensor. A two-dimensional code reader having such a configuration is provided with a function of reading a barcode. In this configuration, since the number of pixels in the horizontal direction of the image sensor (the number of pixels in one pixel row) is about 1200 pixels, a barcode close to a two-dimensional code reader or a barcode with a normal minimum bar width. Can be read sufficiently.

However, the two-dimensional code reader cannot read a far-off barcode or a barcode with a very small minimum bar width. This is because if the barcode is far away or the minimum bar width is thin, the magnification will be small, and the pixel allocation of the sensor when the bar width of the barcode is imaged will be small, whereas the image sensor The bar code cannot be read because the number of pixels in the horizontal direction is small.
JP-A-8-320908

  In order to enable reading of a far-off barcode or a barcode with a very small minimum bar width by a two-dimensional code reader, the number of pixels of the image sensor may be increased, but the number of pixels in the horizontal direction is about 2000. With this configuration, when a QR code is read by such an image sensor having a large number of pixels, the read image data becomes large and the data processing takes time, so that the reading speed decreases. Will occur.

  As an apparatus for solving such problems, an optical information reading apparatus described in Patent Document 1 is known. In this apparatus, a concave mirror is provided outside the imaging lens, and the reflected light of the barcode is reflected by the concave mirror and then imaged on the image sensor (image sensor) through the imaging lens. ing. In the case of this configuration, the angle of view in the bar code array direction can be narrowed by the concave mirror, so that the bar code image can be enlarged and formed on the image sensor. Therefore, it is possible to read a barcode that is far away or a barcode that has a small minimum bar width.

  However, in the configuration of the above publication, since the angle of view is narrowed by the concave mirror, there is a problem that the field of view is narrowed and a wide information code or a large information code cannot be read. In addition, in the case of the configuration of the above publication, there is a drawback that the image is distorted when the curvature of the concave mirror is small. In addition, since the concave mirror with a large curvature is large, the malfunction that a reader main body will enlarge will generate | occur | produce.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image sensor and an information code reader that can read a bar code and the like that are far away, can prevent a reading speed from being lowered, and can read a wide bar code and the like. To provide the equipment.

  The image sensor of the present invention has a plurality of pixels arranged in a matrix and storing charges corresponding to the amount of incident light, and has a function of outputting signals sequentially read from the plurality of pixels in a predetermined cycle time. In addition, the size of the plurality of pixels in the matrix is the same, and the number of pixels in at least one pixel row of the plurality of pixels in the matrix is set to the number of pixels in the other pixel rows. It is characterized in that it is configured to be more than that.

  According to the above configuration, a barcode or the like that is far away can be read by using a pixel row having a large number of pixels. In this case, since only data read by a pixel row having a large number of pixels is processed, data processing (capture processing) does not take time, and reading speed does not decrease. Further, since the angle of view is wide, it is possible to read a wide barcode or the like.

  In the case of the above-described configuration, the output switching unit includes a signal receiving unit, and switches so as to output only a signal read from a pixel in a pixel row having a large number of pixels based on a signal received by the signal receiving unit. It is preferable to comprise so that it may be provided.

  Further, another image sensor of the present invention has a plurality of pixels arranged in a matrix and accumulates charges according to the amount of incident light, and outputs signals sequentially read from the plurality of pixels in a predetermined cycle time. The above-described function is characterized in that the size of pixels in at least one pixel row among the plurality of pixels in the matrix form is different from the pixels in other pixel rows.

  In the case of this configuration, the pixels having different sizes are preferably smaller than the pixels in the other pixel rows. In addition, the pixels having different sizes may have a vertically longer shape than the pixels in other pixel rows. And a signal receiving means, and an output switching means for switching so as to output only signals read from the pixels in the pixel rows having different pixel sizes based on the signals received by the signal receiving means. It is preferable to comprise so that it may be provided.

  The information code reader of the present invention has a function of optically reading an information code and converting it into information such as characters and symbols. The information code reader includes the image sensors described above and a one-dimensional code reading mode and a two-dimensional code. It is characterized in that it has switching means for switching between the code reading mode.

  In the case of the above configuration, it is preferable that the aperture of the imaging lens is configured to be vertically long when the one-dimensional code reading mode is executed. Further, when executing the one-dimensional code reading mode, reading is performed from a pixel row having a large number of pixels or a pixel row having a different pixel size among the plurality of pixels in the matrix form of the image sensor. It is even more preferable that only the received signal is captured.

  Further, it is preferable that the distance between the image sensor and the imaging lens is configured to be variable when the one-dimensional code reading mode is executed and when the two-dimensional code reading mode is executed.

  The first embodiment of the present invention will be described below with reference to FIGS. First, FIG. 2 is a diagram schematically showing the overall configuration of the information code reader 1 of the present embodiment. As shown in FIG. 2, the information code reading device 1 is a gun-type information code reading device, and includes a device main body portion 2 and a grip portion protruding downward from the lower surface portion of the device main body portion 2. 3.

  The grip part 3 is a part that a user (operator) grips with a hand, and a trigger switch 4 is disposed at the left end in FIG. 2 above the grip part 3. The trigger switch 4 is a switch for starting the reading operation of the information code reading device 1, and is configured to continue the reading operation while the user is performing an ON operation (push-in operation).

  An optical system unit 5 is disposed at the left end portion in FIG. 2 inside the apparatus main body 2, and a printed wiring board 6 is disposed on the right side of the optical system unit 5 in FIG. On the printed wiring board 6, various electronic components 7 are mounted, and a mode changeover switch 8 is mounted. The mode switching switch 8 is a switch for switching the reading mode of the information code reading apparatus 1 to the one-dimensional code reading mode or the two-dimensional code reading mode, and is configured to switch the reading mode every time it is operated.

  A rectangular reading port 9 made of a transparent member is provided on the left end surface portion of the apparatus main body 2 in FIG.

  The optical system unit 5 includes an imaging lens 10, an image sensor 11, and an illumination LED (not shown). Light emitted from the LED for illumination passes through the reading port 9 and is irradiated with an information code (one-dimensional code or two-dimensional code) printed on paper or an article to illuminate the information code. . The reflected light from the information code is configured to form an image on the image sensor 11 through the reading port 9 and through the imaging lens 10.

  Here, the image sensor 11 will be described with reference to FIG. The image sensor 11 is composed of, for example, a CCD image sensor or a CMOS image sensor, and has a plurality of pixels 12 that are arranged in a matrix and store charges according to the amount of incident light, and have a predetermined cycle time. A function of outputting signals sequentially read from the plurality of pixels 12 is provided.

  In the present embodiment, the number of pixels of the image sensor 11 is, for example, about 1.3 million pixels. Specifically, in FIG. 1, the number of pixels 12 in the horizontal direction (horizontal direction) is 1280, The number of pixels 12 is 960 (ie, 1280 * 960 pixels). However, in the case of this embodiment, the number of pixels (the number of pixels 12 in the horizontal direction (horizontal direction)) is set to 2000, for example, for the pixels for two rows from the top, that is, the pixel rows 13a and 13b. ing. The size of each pixel 12 in the pixel rows 13a and 13b is the same as the size of the pixels 12 in the other pixel rows.

  In the case of the above configuration, the number of pixels in the top two pixel rows 13a and 13b, which is at least one pixel row among the plurality of pixels 12 in a matrix, is larger than the number of pixels in other pixel rows. It is comprised so that it may become.

  When the reading mode is a one-dimensional code (for example, bar code) reading mode, reading is performed using all the pixels 12 of the image sensor 11. Further, when the reading mode is a two-dimensional code (for example, QR code) reading mode, reading is executed using the pixels 12 of the two pixel rows 13a and 13b in the image sensor 11.

  Specifically, the image sensor 11 includes a signal receiving circuit (signal receiving means) (not shown), and based on signals received by the signal receiving circuit, signals read from all the pixels 12 are received. A first output mode (two-dimensional code reading mode) for output and a second output mode (one-dimensional code reading mode) for outputting only signals read from the pixels in the pixel rows 13a and 13b having a large number of pixels. A built-in output switching circuit (output switching means) (not shown) is provided.

  Next, the operation of the information code reader 1 having the above configuration will be described with reference to the flowchart of FIG. First, in step S1 of FIG. 3, it is determined whether or not the trigger switch 4 is turned on. When the trigger switch 4 is turned on, the process proceeds to “YES” to turn on the illumination LED and expose the information code to be read (step S2).

  Subsequently, the process proceeds to step S3, and it is confirmed whether the set reading mode is the one-dimensional code (barcode) reading mode or the two-dimensional code reading mode. Here, when the two-dimensional code reading mode is set, the process proceeds to step S4, and signals (image data) read from all the pixels 12 of the image sensor 11 are captured. In step S6, the captured image data (captured two-dimensional code) is decoded to be converted into information such as characters and symbols.

  On the other hand, when the reading mode is the one-dimensional code (barcode) reading mode in step S3, the process proceeds to step S5, and the pixels are read from the pixel rows 13a and 13b having a large number of pixels among the pixels 12 of the image sensor 11. Capture only the signal (image data). In step S6, the captured image data (captured barcode) is decoded to be converted into information such as characters and symbols.

  Then, it progresses to step S7 and it is judged whether the decoding process was performed normally. If the decoding process is not normally executed, the process proceeds to “NO”, the process returns to step S2, and the above-described information code reading process is performed again. On the other hand, if the decoding process is normally executed in step S7, the process proceeds to “YES”, and the information code reading process is terminated.

  In addition, the information code reader 1 having the above-described configuration is configured such that the size of the diaphragm of the imaging lens 10 can be varied. As a configuration for changing the size of the aperture of the imaging lens 10, a known configuration used in a camera or the like may be used. In this embodiment, when the barcode (one-dimensional code) reading mode is executed, the diaphragm of the imaging lens 10 is, for example, vertically long so that the size of the diaphragm is increased. In contrast, when the two-dimensional code reading mode is executed, the aperture of the imaging lens 10 is rounded so that the size of the aperture is set to a normal size.

  With this configuration, when reading a barcode, the aperture of the imaging lens 10 is vertically long and larger than usual, so that the amount of incident light can be increased and the barcode reading performance can be improved.

  Further, in this embodiment, as shown in FIG. 4, the distance between the image sensor 11 and the imaging lens 10 is set to the time when the barcode (one-dimensional code) reading mode is executed and when the two-dimensional code reading mode is executed. It is configured so that it can be changed. As a configuration (mechanism) for moving the imaging lens 10 in the vertical direction in FIG. 4, a known configuration (focus mechanism or the like) used for a camera or the like may be used.

  In this embodiment, when the two-dimensional code reading mode is executed, as shown in FIG. 4A, the distance between the imaging lens 10 and the image sensor 11 is shortened. On the other hand, when executing the barcode (one-dimensional code) reading mode, as shown in FIG. 4B, the distance between the imaging lens 10 and the image sensor 11 (pixel rows 13a and 13b) is increased. It is configured as follows.

  With this configuration, when reading a barcode, as shown in FIG. 4B, the angle of view is not so large, and the barcode reading performance can be improved.

  Incidentally, as shown in FIGS. 5A and 5B, in the case where the distance between the imaging lens 10 and the image sensor 11 is not changed, when the barcode is read, as shown in FIG. In addition, the angle of view becomes very large, and due to the effect of aperture efficiency, there is a disadvantage that light does not reach the periphery even though there are pixels, and barcode reading may not be performed normally. It was. On the other hand, in this embodiment, when reading the barcode, the distance between the imaging lens 10 and the image sensor 11 is increased so that the angle of view does not increase as shown in FIG. Since it is configured, the barcode reading performance can be improved.

  According to this embodiment having such a configuration, when reading a two-dimensional code (when executing a two-dimensional code reading mode), the data read by all the pixels 12 of the image sensor 11 is fetched and processed. A two-dimensional code can be read. On the other hand, when reading a barcode (one-dimensional code) (when executing the one-dimensional code reading mode), only the pixel rows 13a and 13b having a large number of pixels in the image sensor 11 are used. In a similar manner to the code-dedicated reader, it is possible to read a bar code or the like far away, and to increase the reading resolution.

  In the case of the above configuration, since only data read by the pixel rows 13a and 13b having a large number of pixels is processed, the amount of data to be processed is reduced, and the time required for data processing (capture processing) can be reduced. Therefore, the reading speed does not decrease. In addition, since the number of pixels increases and the angle of view increases, it is possible to read a wide barcode or the like.

  In the above embodiment, the pixel rows 13a and 13b having a large number of pixels are arranged at the upper end of the image sensor 11. However, the present invention is not limited to this. For example, the second embodiment shown in FIG. As described above, the pixel rows 13c and 13d having a large number of pixels may be arranged in the middle portion of the image sensor 11, and the arrangement positions may be determined as appropriate.

  In each of the above embodiments, the number of pixel rows having a large number of pixels is two. However, the present invention is not limited to this, and the number of pixel rows having a large number of pixels may be one or three or more. Also good.

  FIG. 7 shows a third embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals. In the third embodiment, in order to make the pixel size of the two pixel rows 14a and 14b from the top among the pixels 12 of the image sensor 11 different from the pixels of the other pixel rows, specifically, The vertical and horizontal dimensions of the pixels were each halved. In the case of this configuration, the number of pixels in the pixel rows 14a and 14b is configured to be twice the number of pixels in the other pixel rows, that is, 1280 * 2 = 2560.

  The configuration of the third embodiment other than that described above is the same as that of the first embodiment. Therefore, in the third embodiment, substantially the same effect as that of the first embodiment can be obtained. In particular, in the third embodiment, the size of the pixels of the two pixel rows 14a and 14b is made smaller than the pixels of the other pixel rows, and specifically, the vertical and horizontal dimensions of the pixels are set to 1 respectively. Since the number of pixels in the pixel rows 14a and 14b is set to be twice the number of pixels in the other pixel rows, the chip size of the image sensor 11 should be approximately the same as the conventional configuration. Can do.

  In the above-described embodiment, the pixel rows 14a and 14b in which the pixel size is reduced (the number of pixels is large) are arranged at the upper end portion of the image sensor 11. However, the present invention is not limited to this. As in the fourth embodiment shown in FIG. 8, the pixel rows 14c and 14d having a small pixel size (a large number of pixels) may be arranged in the middle portion of the image sensor 11. The installation position and the number of rows may be determined as appropriate.

  In the third and fourth embodiments, the vertical and horizontal dimensions of the pixels are halved when the size of the pixels in the pixel rows 14a, 14b, 14c, and 14d is reduced. However, the present invention is not limited to this. For example, as in the fifth embodiment shown in FIG. 9, only the horizontal dimension of the pixel in the pixel row 15a is halved and the vertical dimension remains the same. That is, the shape of the pixels in the pixel row 15a may be configured to be vertically longer than the pixels in the other pixel rows.

  In the fifth embodiment having such a configuration, substantially the same operational effects as those of the third and fourth embodiments can be obtained. In particular, according to the fifth embodiment, the area of the pixel of the pixel row 15a is twice the area of the pixels of the pixel rows 14a, 14b, 14c, and 14d of the third and fourth embodiments. The amount of received light can be increased, and the light receiving sensitivity can be increased.

  In the third, fourth, and fifth embodiments, when the pixel is reduced, the vertical or horizontal dimension of the pixel is halved. However, the present invention is not limited to this, and the size is reduced. The ratio may be determined as appropriate.

The figure which shows the pixel of the image sensor which shows 1st Example of this invention. Broken side view of information code reader flowchart (A) is a view showing the positional relationship between the image sensor and the coupling lens in the two-dimensional code reading mode, and (b) is a positional relationship between the image sensor and the coupling lens in the barcode (one-dimensional code) reading mode. Figure FIG. 4 equivalent diagram showing a comparative example FIG. 1 equivalent view showing a second embodiment of the present invention. FIG. 1 equivalent view showing a third embodiment of the present invention. FIG. 1 equivalent view showing a fourth embodiment of the present invention. FIG. 1 equivalent view showing a fifth embodiment of the present invention.

Explanation of symbols

In the drawings, 1 is an information code reading device, 2 is a device main body, 3 is a grip portion, 4 is a trigger switch, 8 is a mode switch (switching means), 9 is a reading port, 10 is an imaging lens, and 11 is an image. Sensors, 12 are pixels, 13a and 13b are pixel rows, 14a and 14b are pixel rows, and 15a is a pixel row.

Claims (10)

In an image sensor having a plurality of pixels arranged in a matrix and storing charges according to the amount of incident light and having a function of outputting signals sequentially read from the plurality of pixels in a predetermined cycle time,
The plurality of pixels in the matrix are made the same size, and the number of pixels in at least one pixel row among the plurality of pixels in the matrix is made larger than the number of pixels in other pixel rows. An image sensor characterized by being configured as described above. A signal receiving means;
2. An output switching unit that switches to output only signals read from pixels in a pixel row having a large number of pixels based on a signal received by the signal receiving unit. The image sensor described. In an image sensor having a plurality of pixels arranged in a matrix and storing charges according to the amount of incident light, and having a function of outputting signals sequentially read from the plurality of pixels in a predetermined cycle time,
An image sensor comprising: a plurality of pixels in a matrix shape, wherein a pixel size of at least one pixel row is different from pixels of other pixel rows.   The image sensor according to claim 3, wherein the pixels having different sizes are smaller than the pixels in the other pixel row.   The image sensor according to claim 3, wherein the pixels having different sizes have a vertically long shape as compared with pixels in the other pixel rows. A signal receiving means;
An output switching means for switching to output only signals read from pixels in pixel rows having different pixel sizes based on a signal received by the signal receiving means. The image sensor according to any one of 3 to 5. In an information code reader having a function of optically reading an information code and converting it into information such as characters and symbols,
While comprising the image sensor according to any one of claims 1 to 6,
An information code reading apparatus comprising switching means for switching between a one-dimensional code reading mode and a two-dimensional code reading mode.   8. The information code reading apparatus according to claim 7, wherein when the one-dimensional code reading mode is executed, the aperture of the imaging lens is configured to be vertically long.   When the one-dimensional code reading mode is executed, a signal read from a pixel row having a large number of pixels or a pixel row having a different pixel size among the plurality of pixels in the matrix form of the image sensor. 8. The information code reader according to claim 7, wherein only the information is read. 8. The distance between the image sensor and the imaging lens is configured to be variable when the one-dimensional code reading mode is executed and when the two-dimensional code reading mode is executed. Information code reader.

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