JP3668752B2 - Identification code reader and display color display - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The invention according to the claims provides an identification code reader that can accurately read an identification code (such as a barcode) displayed on a color display, and an identification code that can be easily read by a conventional reader. The present invention relates to a color display that can be displayed.
[0002]
[Prior art]
A bar code representing a character by a combination of a plurality of lines is printed on a product or its packaging, and is used for sales management of the product by reading it with a reader (bar code reader). .
[0003]
A barcode reader includes a light source such as an LED (light emitting diode), an optical sensor such as a CCD (charge coupled device), and a signal processing unit that processes an output of the optical sensor as main components. Light is emitted from a light source provided in the vicinity of the front end and applied to the barcode on the printing surface, and the reflected light is taken from the light receiving window and applied to the optical sensor. A signal processing unit or the like converts a signal generated by the optical sensor upon receiving the light input into an electric signal or the like that is easy to handle. That is, the conventional reading device is configured to read a barcode printed on a paper surface or the like by applying light to the barcode and receiving the reflected light.
[0004]
However, in recent years, proposals have been made for efficient product management by displaying a bar code on the display of a personal computer or POS system and reading it with a reader. For example, Patent Document 1 below discloses such a system.
[Patent Document 1]
Japanese Patent Laid-Open No. 10-134250
[0005]
[Problems to be solved by the invention]
When displaying a barcode on a color display such as a personal computer, it is extremely difficult to read the barcode stably and accurately with a conventional reader. The reason is as follows.
[0006]
B) The pixel pitch (generally about 14 μm) of the optical sensor used in the bar code reader is much smaller than the pitch of the RGB phosphors of the display (generally about 100 μm). Reads RGB colors as they are. In other words, each pixel of the photosensor outputs a signal that is separated into RGB colors, not the white color of the space in the barcode or the color of the bar, and thus has a different output level from the white color on the barcode. That adversely affects the reading of barcodes.
[0007]
B) In the case of a CRT display using the raster scan method, the phosphor emits light when the scanning electron beam hits the tube-like phosphor, so that each pixel on the screen does not always emit light. In practice, light emission is repeated approximately once every 11 to 16 ms for a time of about 1 ms. On the other hand, since the optical sensor in the conventional general barcode reader accumulates and reads out charges for approximately 10 ms, it may not be able to pick up the light emitted from the tube surface. This also has an adverse effect on barcode reading.
[0008]
C) When the light source of the reading device emits light as in the case of reading a printed barcode, the light is strongly reflected on the tube surface of the display, preventing accurate reading of the barcode.
[0009]
The above situation is not limited to a normal bar code, but is a common problem when various identification codes are displayed on a color display and are read by a reading device for product management or the like. It is.
[0010]
The invention according to the claims is to solve such a problem. That is, the present invention provides a reading device that enables stable and accurate reading of an identification code on a color display, and also provides a color display that can display the identification code so that it can be easily read by a conventional reading device. It is.
[0011]
[Means for Solving the Problems]
The identification code reading device according to claim 1 is an identification code reading device for reading an identification code on a color display by using a photosensor of a plurality of pixels, and each pixel of the photosensor generated according to the wavelength of light. A means for reducing (that is, flattening) the difference in output intensity is provided.
The “color display” here may be any display method such as a CRT method, a liquid crystal method, a plasma method, and an EL method. “Identification code” includes barcodes, various two-dimensional codes, and any other identification symbols. The “optical sensor” includes a CCD type, a reduction type sensor using a CMOS and a CDS type, and a contact type sensor (Cds type, a-Si type, multi-chip type, etc.).
[0012]
According to the reading device of this claim, the above means, that is, the means for reducing the difference in the output intensity of each pixel of the photosensor generated according to the wavelength of light is the three primary colors of RGB (red, green, and blue) on the display. The same is true when the three primary colors of CMY, that is, cyan, magenta, and yellow are used), and the output difference of each pixel of the photosensor based on the difference in each color can be weakened. Therefore, even if each pixel reads each RGB color as it is because the pixel pitch of the optical sensor in the reading device is smaller than the RGB phosphor pitch of the display, the output difference for each color is small, and the identification code is read. The adverse effect on is small. That is, this reading apparatus can appropriately solve the above-mentioned problem (b) and can stably read the identification code on the color display with a high degree of accuracy.
[0013]
According to a second aspect of the present invention, there is provided the reading device according to the second aspect of the present invention, particularly as a means for reducing the difference in output intensity of each pixel of the photosensor generated according to the wavelength of light. Is provided. This color filter is preferably one in which the transmittance is set so that the output of each of the RGB pixels when the color display displays as white can be detected by the optical sensor with substantially the same intensity.
[0014]
This reading apparatus also exhibits the same operation as the apparatus described in claim 1. However, the arrangement of the color filters as described above is simpler and requires less cost than using an optical sensor having a special function or causing the signal processing unit to perform new processing. There is an advantage.
[0015]
As the “means for reducing the difference in output intensity of each pixel of the photosensor generated according to the wavelength of light” described in claim 1, a color filter (optical filter) is provided as in the above (claim 2). Other than that, you can do the following:
A light sensor such as a color CCD having a function of reducing the difference in output intensity of each pixel (that is, including the above means) is employed. For example, the characteristics of an on-chip color filter in a color CCD are made to flatten the output intensity of the light emission wavelength of the display, or three color filters of RGB (or CMY) are mounted on one pixel in the color CCD. The size (area ratio) of each color filter on the pixel is set so that the output intensity of the emission wavelength of the display is flat.
• Use a processing circuit that averages multiple pixels of the output signal from each pixel of the photosensor. In this case, the number of pixels to be averaged is preferably a number of pixels corresponding to three RGB pixels on the display. If it is less than that, it is often impossible to sufficiently reduce the difference in output intensity of each pixel of the photosensor, and if it is more than that, the reading accuracy or resolution may be insufficient. A plurality of pixels to be averaged may be fixed, but it is also preferable to take a moving average by changing appropriately.
[0016]
According to a third aspect of the present invention, there is provided a reader for an identification code for reading an identification code on a color display using a plurality of photosensors. A means for outputting as a signal is provided.
[0017]
According to such a reading apparatus, a signal obtained by mixing a plurality of pixel colors (RGB) on the color display is output as a signal of each pixel of the optical sensor. That is, the output difference of each pixel of the photosensor based on the difference between the RGB colors on the display is weakened. Therefore, even if the pixel pitch of the photosensor in the reading device is smaller than the pitch of the RGB phosphors of the display, the output difference in each pixel of the photosensor becomes small, and the problem on the above a) is solved and identification on the color display The code can be read fairly accurately and stably.
[0018]
According to a fourth aspect of the present invention, as the above-described means for outputting a signal for a plurality of pixels of the color display as a signal of each pixel of the photosensor, the reading device according to the fourth aspect particularly forms a plurality of pixels of the color display on one pixel of the photosensor. It is characterized in that an optical path (optical path such as a lens or a mirror surface) having such a resolution is used.
[0019]
In addition to the above-described operation, this reading apparatus has an advantage that the configuration is simple and the required cost is low. This is because the optical path as described above can be easily realized at low cost by optical means such as a lens or a mirror surface, and the output is stable and does not change.
[0020]
It is most preferable that the resolution of the light path is about 3 pixels, that is, the number of pixels of the color display imaged on one pixel of the photosensor is 3. If three or more pixels on a color display including RGB form an image on one pixel of the photosensor, light of a color close to human recognition is incident on each pixel of the photosensor, and reading is particularly stable. It is. However, if four or more pixels of the color display are imaged on one pixel of the optical sensor, it is disadvantageous in terms of resolution compared to the case of three pixels.
[0021]
The means for outputting a signal for a plurality of pixels of a color display as a signal of each pixel of the photosensor as described in claim 3 is as described above (claim 4). It is preferable to use an optical path having a resolution such that a pixel forms an image, but the following may also be used. That is,
-By making the pixels of the photosensor with a large pitch or by arranging the pixels on the photosensor diagonally, each pixel is equivalent to a plurality of pixels of the display (for the same reason as above, about 3 pixels are preferable) ).
・ While reading the output signal of the photosensor while making the light of one pixel of the display incident on each pixel of the photosensor, average processing is performed for multiple pixels (preferably about 3 pixels) of the sensor. One signal.
[0022]
The identification code reading device according to claim 5 is an identification code reading device that reads an identification code on a color display using a photosensor of a plurality of pixels, and charges the sensor unit by photoelectric conversion in the photosensor. The accumulation time should be the same as (or synchronized with) the scanning time in a color display using a raster scan method, or longer (that is, asynchronized and the time for accumulating charges in the sensor unit is lengthened). Features.
[0023]
Since the charge accumulation time in the optical sensor is equal to or longer than the scanning time in the color display, the optical sensor of the reading device reliably captures and outputs intermittent light emission of the pixels on the display. That is, the reading device can accurately and stably read the identification code on the color display that is repeatedly displayed for a short time as shown in (b).
[0024]
The identification code reading device according to claim 6 is further provided in the vicinity of the light receiving window so that each of the above-described reading devices can also read an identification code on a non-light emitting surface (printed on paper or products). A light source is provided, and the light quantity of the light source can be changed (including turning on and off the light source).
[0025]
According to this reader, in addition to being able to read the identification code on the color display with high accuracy as described above, it is also possible to read the identification code printed on a non-light emitting surface such as a paper surface with high accuracy as well. It is. As described above, a light source is provided near the light receiving window, and the light quantity of the light source can be changed.
a) When reading the identification code on the color display which is the light emitting surface, the light quantity of the light source is lowered (or made zero) so that it is not affected by the reflection on the tube surface (therefore, c) On the other hand,
b) When the identification code on the non-light-emitting surface is read, the amount of light is increased, so that accurate reading can be realized using reflected light in the same way as reading in a normal reading device.
[0026]
When changing the amount of light as described above, it is preferable to switch by operating a manual switch or the like depending on whether the identification code on the light emitting surface is read or the one on the non-light emitting surface is read. However, in order to automate the change in the amount of light, for example, a sensor capable of sensing the light emission of the reading object is provided in the reading device, and when the sensor senses light from the light emitting surface, the light amount of the light source is automatically reduced (or To zero). As the above-described sensor for detecting light emission, a part of a photosensor such as a CCD arranged for reading the identification code may be used.
[0027]
Note that the features described above improve the identification code reading performance of the device when any of the features is provided in the reading device. If it is provided, it is a matter of course that more preferable reading performance is exhibited.
In addition, in order to smoothly read both the identification code on the color display and the identification code on the non-light-emitting surface, light having a wavelength overlapping the light emission wavelength of the color display from the light source to the non-light-emitting surface (for example, RGB average) It is also meaningful to emit green light having a wavelength close to that of the wavelength.
[0028]
A color display for displaying an identification code according to a seventh aspect is characterized in that a color filter for reducing (that is, flattening) a difference in wavelength with respect to the output intensity of light is provided on the surface of the display portion. The color filter may be provided in a form that is applied to the surface of the display portion of the display, or another filter member (made of glass or plastic) may be disposed outside the display portion of the display. Good. Note that the color display of this claim and the following claim is “for display of an identification code”, but is not necessarily “for display of an identification code”. As described above, various display methods such as a CRT method, a liquid crystal method, a plasma method, and an EL method are included. .
[0029]
According to this color display, the difference in light emission intensity between the pixels based on the difference in RGB is weakened by the color filter. For this reason, the identification code displayed on the display has a smaller reading error even when a conventional reading device having a pixel pitch smaller than the pitch of the RGB phosphors on the display is used as described in (a). . Therefore, even with a conventional reader, it is possible to read the identification code on the color display with an accuracy that does not cause a practical problem.
[0030]
  In addition,The color display for displaying the identification code has an anti-reflective surface on the display surface (outermost surface).It is also preferable to do so.The surface subjected to the antireflection treatment may be provided by applying an antireflection treatment to the surface of the display portion of the display, and a filter member (made of glass or plastic) subjected to the treatment is attached to the display. It may be provided by being arranged outside the display portion.
[0031]
  That wayEven if the light source of the reading device emits light according to the conventional method, the light is not strongly reflected on the tube surface of the display due to the action of the antireflection treatment surface. For this reason, there is little risk of the reading being disturbed by the reflected light. Therefore, even a conventional reading device used for reading a code on a non-light-emitting surface can read the identification code on the color display almost accurately. is there.
[0032]
  Also,The color display for displaying the identification code displays the barcode as the identification code in a form in which each bar extends perpendicularly to the direction in which the RGB pixels of the display are continuously arranged.It is also preferable thatThe color display 3 in FIG. 4 is an example. In this case, the RGB pixels are continuous vertically (in the vertical direction of the display portion 3a), whereas the barcode C3 is perpendicular to the arrangement of the pixels. The bar CB and the space CS are displayed so as to extend in the horizontal direction (left and right direction of the display portion 3a).
[0033]
  Like thatIn a color display, when a barcode is displayed on the screen, each bar is displayed so as to extend in a direction perpendicular to the direction in which the RGB pixels are continuously arranged, that is, in a direction that always crosses the three RGB pixels. As a result, the barcode element representing the signal is composed of a large number of RGB elements (for three colors), so that there is little influence such as mismatch with the pixel pitch of the optical sensor, and information is read stably. It becomes possible.
[0034]
  others,The color display for display displays a barcode as an identification code by selecting a color between each bar and the background so as to increase the contrast for the optical sensor.It may be good.
[0035]
If a bar code is displayed with high contrast in this way, even if each pixel reads each RGB color on the color display as it is with a conventional reading device with a small pixel pitch of the photosensor, a reading error will occur. There is little occurrence of. The reason for this is that the lightness is greatly different between the case of reading the bar portion of the barcode and the case of reading the space portion, so that the influence due to the difference in each RGB color is relatively small.
[0036]
  Claim 8The display color display described in 1) selects the barcode as an identification code and the background color between the bars so that the outputs of the photosensors receiving the background pixels between the bars have almost the same intensity. It is characterized by displaying.
[0037]
In this way, when the background color between the bars is selected and displayed so that the outputs of the photosensors receiving the background pixels between the bars have substantially the same intensity, the pixel pitch of the photosensors is small. Even if each pixel reads the RGB colors on the color display as they are, the reading error is small. The reason is that the signal level difference of each pixel when reading the space portion of the barcode is almost eliminated, so that it is easy to recognize the space.
[0038]
These characteristics of the color display also bring about an effect as described above when any one of them is provided in the color display. Needless to say, a more advantageous effect can be obtained when several of the above features are simultaneously provided in one color display.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
One embodiment of the invention is shown in FIGS. FIG. 1 is a perspective view showing an identification code reader (barcode reader) 1 (displayed through the inside), and FIG. 2 shows an optical filter 15 used in the reader 1. It is a diagram which shows a characteristic. FIG. 3 is a front view (FIG. 3A) showing a CRT color display 2 that displays a barcode C2, a two-dimensional code D, and the like, and shows an RGB pixel arrangement in a portion b on the tube surface. It is a detailed view (the same (b)).
[0040]
The schematic configuration of the reader 1 is as shown in FIG. 1, and the following is attached to a casing 1a having an output cable 1b. First, a light source 11 composed of an LED is provided in the vicinity of an end where reading is performed, and a light receiving window 12 is opened. This is because the light emitted from the light source 11 and reflected by the identification code C1 on a non-light emitting surface such as a paper surface is taken in from the light receiving window 12. The LED as the light source 11 has a wavelength characteristic centered at about 600 nm. A reflection mirror 13, an optical filter 15, a lens 16, and the like are arranged in a portion following the light receiving window 12 inside the casing 1a, and a photosensor 20 composed of a CCD is attached to the end of the light path. The output of the optical sensor 20 is sent from the cable 1b to an external device (such as a personal computer or a POS system) via the drive circuit unit 21 and the signal processing unit 22.
[0041]
The reading device 1 in FIG. 1 not only can read the identification code C1 on the non-light emitting surface, but also displays the display portion (that is, the tube surface which is the light emitting surface) 2a of the color display 2 as shown in FIG. The displayed identification code C2 can be read. In order to be able to read both the identification codes C1 and C2, the reader 1 shown in FIG. 1 is devised as shown in a) to d) below.
[0042]
a) A color filter having a transmittance distribution as shown in FIG. 2 is used as the optical filter 15 provided in the optical path between the light receiving window 12 and the optical sensor 20. The transmittance distribution in FIG. 2 has a higher transmittance for wavelengths including three colors of RGB (460 to 620 nm) than those for wavelengths in the outer region, and the color display 2 displays white. In this case, the output of each pixel of RGB is set to be detected by the optical sensor 20 with substantially the same intensity. For example, as a specific example, the optical filter 15 is a color filter # 4415 (CalColor 15 Green) manufactured by rosco (USA) or an equivalent thereof. When such a filter 15 is used, firstly, when reading the identification code C1 on the non-light-emitting surface, the identification code C2 on the display 2 is displayed together with the light (red light) emitted and reflected by the light source (LED) 11. While reading, the light (RGB) emitted from the display 2 is transmitted at a high rate so as to surely reach the optical sensor 20, while it is difficult to transmit light having a wavelength that tends to be a disturbance in the external region. is there. Second, the output level of each element color of the photosensor 20 generated according to each RGB wavelength emitted from the color display 2 is flattened (uniformized), so that the pixel array of the photosensor 20 is the RGB of the display 20. The reading error of the identification code C2 due to the smaller pitch than the phosphor arrangement is made difficult to occur.
[0043]
b) The focus on the optical sensor 20 is defocused by selecting or arranging the resolution of the reflecting mirror 13 and the lens 16 so that three pixels (one set of RGB) on the color display 2 form an image on one pixel of the optical sensor 20. I have to. By doing so, the element colors on the display 2 are appropriately mixed and incident on each pixel of the photosensor 20, and the output difference of each pixel of the photosensor based on the difference of each RGB color on the display 2 is weakened. As a result, the reading error of the identification code C2 due to the pixel array of the optical sensor 20 being smaller in pitch than the RGB phosphor array of the display 20 is less likely to occur due to this point, and the reading accuracy is increased.
[0044]
c) The charge accumulation time in the optical sensor 20 is set to approximately 20 ms, which is longer than the general scanning time (11 to 16 ms) in the color display 2. Thereby, although the pixels on the display 2 emit light intermittently, the reading device 1 can surely capture the light by one reading and exhibit high-precision reading ability.
[0045]
d) The light quantity of the light source 11 is set to be about half that of a conventional reading apparatus that reads only the identification code C1 on the non-light emitting surface. Even when the amount of light is reduced in this manner, in this reading apparatus 1, the charge accumulation time of the optical sensor 20 is lengthened as described in c) above, so that the identification code C1 on the non-light emitting surface can be read smoothly as before. Further, when the identification code C2 on the color display 2 is read by reducing the light amount of the light source 11, the reflection of light on the display portion (tube surface) 2a becomes weak, and therefore the reading accuracy of the identification code C2 is improved. improves.
[0046]
Next, FIG. 4 shows a display portion (tube surface) 3a so that it can be easily read by the reading device 1 of FIG. 1 or by a conventional reading device configured to read the identification code C1 on the non-light-emitting surface. A CRT color display 3 for displaying an identification code is shown above.
[0047]
This color display 3 has the following steps e) to g) for the purpose of displaying the barcode C3, which is an identification code, in an easy-to-read manner as described above.
[0048]
e) As shown in the figure, the bar code C3 is vertically arranged, that is, the plurality of bars CB and the space CS are displayed so as to be arranged vertically with the length direction being horizontal. That is, as shown in FIG. 4C, the RGB pixels are continuous vertically (in the vertical direction of the display portion 3a) in the display portion 3a of the display 3 (this is the case in the display portion 2a of FIG. 3B). However, the bar CB and the space CS are extended and displayed in a direction perpendicular to the continuous direction of each pixel (that is, the left and right direction of the display portion 3a). When displayed in this way, as shown in FIG. 4C, the bar CB and the space CS of the barcode C3 are displayed extending in a direction crossing the RGB3 pixels forming the set. As a result, since the barcode element representing the signal is composed of a large number of RGB elements (for three colors), there is little influence such as mismatch with the pixel pitch of the optical sensor, and the bar on the display 3 is displayed. The code C3 can be read with sufficient accuracy.
[0049]
f) The color display layer 3a of the color display 3 is integrally formed with a color filter layer for reducing the difference in light intensity for each wavelength. As the color filter, # 4415 (CalColor 15 Green) manufactured by rosco (USA) is used as the color filter. Therefore, according to the transmittance similar to that in FIG. 2, light having a wavelength including three colors of RGB is particularly high. Make it transparent. In such a color display 3, the difference in light emission intensity between the pixels based on the difference in RGB is weakened. Therefore, when a conventional reading device having a photosensor with a pixel pitch smaller than the pitch of the RGB phosphor on the display 3 is used. In addition, the identification code displayed on the display 3 can be read accurately.
[0050]
g) An antireflection treatment layer is integrally formed on the surface (outermost layer) of the display portion 3a. When the identification code on the display 3 is read using a conventional reader for reading the identification code on the non-light emitting surface, the light source of the apparatus emits strong light, but the display 3 has an antireflection treatment layer. For this reason, the intensity of reflected light at the display portion 3a is considerably reduced. If the intensity of the reflected light is low, there is little possibility that the reading will be hindered, so that the identification code on the color display 3 can be read with sufficient accuracy even by a conventional reading device.
[0051]
【The invention's effect】
According to the identification code reading device of the first and third aspects, the identification code on the color display can be stably stabilized even when the pixel pitch of the optical sensor in the reading device is smaller than the pitch of the RGB phosphors of the display. Can be read.
The reading apparatus according to claim 2 or 4 has an advantage that the configuration is simple and the required cost is low.
[0052]
According to the identification code reader described in claim 5, since the optical sensor reliably captures intermittent light emission of pixels on the color display, the identification code displayed on the display can be read accurately and stably. Is possible.
[0053]
According to the reading device of the sixth aspect, both the identification code on the color display and the identification code printed on a non-light emitting surface such as a paper surface can be read with high accuracy.
[0054]
  Claim 7Or 8According to the color display for displaying the identification code described in the above, the identification code can be read accurately even when a conventional general reader having a pixel pitch smaller than the pitch of the RGB phosphors on the display is used. Can be displayed.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a reading device 1 according to an embodiment of the invention (displayed through the inside).
2 is a diagram showing light transmission characteristics by wavelength for the optical filter 15 used in the reading apparatus 1 of FIG. 1; FIG.
FIG. 3 is a front view (FIG. 3A) showing a CRT color display 2 for displaying a barcode C2, a two-dimensional code D, and the like, and details showing an RGB pixel arrangement in a portion b on the tube surface. It is a figure (same (b)).
FIG. 4 is a front view (FIG. 4A) showing a color display 3 that displays an identification code so that it can be easily read by a conventional reading device, and a front view of a bar code C3 displayed on part b on the display 3. FIG. 6B is a detailed view (part (c)) of part c showing an RGB pixel array on the display 3 displaying the barcode C3.
[Explanation of symbols]
1 Reader
2.3 Color display
11 Light source
12 Light receiving window
15 Optical filter
20 Optical sensor
22 Signal processor
C1, C2, C3, D identification code

Claims (8)

An identification code reader for reading an identification code on a color display using a photosensor having a plurality of pixels,
An identification code reader, comprising means for reducing a difference in output intensity of each pixel of a photosensor generated according to a wavelength of light.   The color filter is provided in any part from the light receiving window to the photosensor as the means for reducing the difference in output intensity of each pixel of the photosensor generated according to the wavelength of light. A device for reading the described identification code. An identification code reader for reading an identification code on a color display using a photosensor having a plurality of pixels,
An identification code reader comprising means for outputting a signal for a plurality of pixels of a color display as a signal of each pixel of an optical sensor.   As a means for outputting a signal for a plurality of pixels of the color display as a signal of each pixel of the photosensor, an optical path having a resolution such that a plurality of pixels of the color display is formed on one pixel of the photosensor is used. The identification code reader according to claim 3. An identification code reader for reading an identification code on a color display using a photosensor having a plurality of pixels,
An identification code reading device characterized in that a time for accumulating charges in a sensor portion by photoelectric conversion in an optical sensor is equal to or longer than a scanning time in a color display employing a raster scan method.   6. The identification code according to claim 1, wherein a light source is provided in the vicinity of the light receiving window so that the identification code on the non-light emitting surface can be read, and the light quantity of the light source can be changed. Reader.   A color display for displaying an identification code, characterized in that a color filter for reducing the difference in wavelength for the output intensity of light is provided on the surface of a display portion. An identification code display color characterized by displaying a barcode as an identification code by selecting a color so that each output of a photosensor that receives each pixel in the background between the bars has almost the same intensity. display.

Images