JPS5927377A - Optical information reader - Google Patents

Abstract

PURPOSE:To prevent a partial read failure, by making the circumferential part higher than the center part of optical information with respect to photoelectric conversion seusitivity. CONSTITUTION:Red light emitting diodes 1, 2 of a portable reader are made to emit light to a bar-code label 4 printed by a heat sensible printer, the light is irradiated through a lens 3, and an image is formed on an image sensor 9 on which a photo-element is arrayed. Intensity of illumination of light emission of two red light emitting diodes of the outside is made higher than that of light emitting diodes 2, 2 of the inside, therefore, a bar-code video forming an image on an image sensor 9 has equalized brightness extending over the whole area, and the level of an electric signal is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to
, relates to an optical information reading device for reading optical stacks of characters and the like.

Conventionally, this type of device records optical information such as barcodes and characters, irradiates the label with bright light using a tungsten lamp, and uses the reflected light to pass through a semicylindrical lens. When the convergence I+ (< 191 L), the information image by the reflected light is imaged on the surface of the reading sensor IJ (image sensor), and the image is converted into an electric signal by the reading operation by electronic scanning of this sensor. is being converted to .

For illumination, a plurality of tungsten lamps of the same 116 degrees are arranged in parallel to uniformize the illumination over the entire area.

At that time, the light Δ for illuminating the label was set to have an intensity of 6 degrees (as long as the illuminance of the tungsten lamp used was sufficient).

When we proceeded with the study of reducing the illuminance of the light source for the device, we found that when the sensitivity limit of the image sensor was approached, the optical information 111 (external reading failure) It was found that this occurs.The causes are: - Variations in the characteristics of the image Q sensor, variations in the arrangement of the optical system, and light source 0.
Moon (((As a result of considering various aspects such as variations in power, the optical path length in the optical system until the image of optical information is formed on image sensor 1-4 is Compared to the length of the reflected light liA at the center, both jmh of the information
Is the reflected light of the 11R length more swollen? The difference in the brightness of the image due to the difference in optical path 1& has a large effect on the fact that the output signal of the image hinsa is biased in magnitude' (
Noko is revealed to be there.

The present invention solves this problem by applying our C1 optical information (
February (((Illuminance of the bright light source is r+)), 'C and partially, Ilv is 11J゛ to prevent defects.
-1 target is 'C.

To this end, in the present invention, an optical information + II reading device equipped with an electronic scanning thread reading sensor; ρ: I:; The center of the optical information 111;
A correction means is provided to satisfy 'li <'4.

Hereinafter, the present invention will be explained with reference to the drawings and an actual HFB example.

Figure 1 is that l? A 1-minute cutaway block diagram and Figure 2 are exploded explanatory diagrams of the main parts. 1 is a red light emitting diode 1 with a luminance of 660±fi (1) used for light dI (1). 2 is a red light-emitting diode of the same kind arranged in parallel with the color light-emitting diode A-1. By changing the resistance value of the resistors connected in series, the illumination intensity is set to be slightly lower than that of the two outer light emitting diodes 1 and 1. 3 is a semicylindrical lighting lens that directs the illumination light from the red light emitting diodes 1 and 2. 6 4 is the label of the recording medium, and the optical information bar: + -l' 5
+: Printed.

6 is a ψ plane j-mata, which changes the strength by reflecting the bar's 1-travel 43I; 7 is the lens (7 bars 1-I' anti-R 1 from label 4) Y
,of! IS light 1, aperture member)
>, M
Su1!゛Cil,! l l;L n]A l[K
(Hyy Rido L-'CO) Create many AI/elements into a line with Image Runly! 1 nibe °C-・Fukinoji 1 +1
1 with a resolution of 24 bits? (red light)
”: Spectral sensitivity peak Mi near (i (l nm))
The area is also a) thing. 10 are the cases I have on hand, of which! ′! 1; It connects to the data processing device through the signal command which sends and receives electrical signals to each of the input terminals 41 and 41.
Adjust the illuminance of '°・ru) 1 ((degrees ρ^th and times 11δ).

FIG. 3 shows an electrical circuit for 1) red light emitting diodes 11, 20, IQ, and 4 for adjustment and setting. Each red light emitting die t −F ],! 1 for each 12.2
1 ((Degree adjustment + 1811 resistance R1, 1 - 2.1 - 3
,! Connect connector 4 and power up C4f, inside 211
Resistor R2 connected to AI's red light emitting diode f-ode 2.2
, I'23 is the same resistance 11-1, and the I side, 2
The resistors R+, R, and I connected to the red light emitting diode (11^1) are set to a smaller resistance value. (
The central part becomes (It < , and the peripheral part becomes (not
``(It gradually becomes -゛6.

fl-゛(、U・＼る４．にのば２ I -1' 5
As shown in Figure 2, the illuminance distribution of the Le 1C line, which is perpendicular to the bar, is low in the center, and gradually increases to IrI+ in the periphery.

In addition, Fig. 4 shows the i;I: :)u characteristic diagram,
Image sensor 9's spectral sensitivity 1 (1, 8), wavelength distribution characteristics B of light emitting diodes 1 and 2, and small reflection of black (black bar) of bar 2+-p label 4 printed with a thermal printer It represents IJC.Here, luminous goo (
', A-1'' l, 2 has an emission spectrum distribution of 660
′! : 3 (l nm, ・The peak 41! of the spectral sensitivity characteristic of C measurement sensor 9 is shown as an example at 7 (10 nm, and when the reflection of the bar is small) According to No. 11, the emission spectrum range of illumination light from a light source is limited to a wavelength range of 660±60 nm.

In the next section, I will explain the movement of 1st article (1 is the beginning of C so σ month'1 movement).

〈;,〈〈〈〉〈〈〉〈〉〈〉〈〉〈〈〉〈〉〈〉〈〉〈〈; 'li A11i l
The red light emitting die A-1' I and 2 of Lee's 4 (1^1) enters the light emitting state. Te bar: + -l;
'Label 4 is irradiated first. This nine 1t (l Ifl,
By I, the bar two 1-ton bell, 4-ton own bar,
No person (l; j on the bar has different reflectance, and the light intensity distribution corresponds to bar 2+ -J:5. Lens 7, aperture full
Through the optical system of t 4.18"(-(Magemun'4)
No.9 F A1・Reading line 1'+1 where elements are lined up=Bar 2 in the orthogonal direction of each bar! - 1 video is tied.

Gt'C3 Electronic control amount I1 of this image processing 1)
By M? In the 11th scanning reading 11N, the 1'-1' image can be converted to electrical (-t'l).

At this time, the light +1. between the reading line -1 of the image U 9 and the bar 'l' 5, on which the image 119 of the bar 21-5 of the bar 21-travel 41 is formed. R length is Berni I
-Central! Compared to the length of the reflected light 118 of No. 11, the reflected light of 1 part of Bar 2 1-1 is 1. The force of No. 81 is the largest, but the outer 211^1 σ5, colored light Da, Io 1゛1.1's emission from the inner one III
Since the image Q7 is 91-, the bar 2 + -1 ゛ image formed on the image Q7 has a uniform brightness over the entire area, and the image J is converted to 91-. Stabilizes the level of electrical signals 5I and simplifies signal processing.
1 (conversion, d'li 4111 degree conversion can be achieved ゛4, (not゛ζlight ljノ) Can prevent 11.

Furthermore, since the emission amplitude of the red light) and the die j-1゛I,2 is around 6 (i (] nm),
On a thermal printer - (111 printed Verni J-F5
tJ, ri's anti-1・1 special I11 and 'c Pl,, shown in special figure 1110 of Figure 4. % ~ 55 white culm degree, l
I can do that. At this time, the anti-n・I of the black bar; 14
It is desirable that the value be close to zero, but the image sensor v
G
41 around 60 nm, color light is the most suitable wave 1 overall
It's C's turn.

Looking at the reflectance of the black color printed on a 'C111' printer using a 900nm wave r;
ontraSt 5 standard ) 41Y =
0° (12), M length fi G (l nm'c approx. 0.5
3 (, P C34N = (].

37), approximately +1.011 at wave 14550 nm (PC
341Y = 0゜81)), the reflectance of the horse bar is high for long wavelengths, and the reflectance of the black bar becomes higher as it goes to visible light ([(<
Then, f' C5 (Ill becomes 1 and goes to C., 1
:' It can be seen that C1 shortwave number 1 is better, but the IPI at the spectral sensitivity of the image sensor 9 of the Sirini 1 thread semiconductor
If you look at the combination l゛ζ, beak 4 + J Kafi 50~!
It is between l 00 nm. For this purpose, short wave 1. I and...
The sensitivity of the image sensor 5) deteriorates and the efficiency decreases by 1ξ-. , the spectral sensitivity of image sensor 9 is G 00 nm
The holding capacity is approximately El (to 19g/9 [196°C)
Shima U.

Tometotototoro', et al., the fouling rate of the black bar printed with a thermal printer and the spectral sensitivity L1 characteristic of the image Unri 9 ('
1% l from the 1ilII force, then 66 (1:' (radiation within the 1 nn41i circle) °C j, vector 1, v light emitting diode, optical information reader KL11)
Y; It turns out that it is good to add 4 degrees to i+1M for convenience.

Nida, other normal printing, t-, t, 'r are also 1
．． If I' CS 4+α, which is defined in the IIs standard, is higher than the standard, there is a problem (it can be read).

In addition, by using a tungsten lamp with a large amount of infrared light components, a C1 red light emitting diode,
2 has no infrared wavelength component, so image sensor-1) 9
It is also possible to prevent problems such as non-uniform sensitivity to infrared light (!

In addition, since the red light emitting diode L2 of il'& 5ilt Ifl: is used as the light source, the light source can be made smaller than when using a tungsten lamp. Furthermore, the amount of light f11 involved in the light emitting action can be made very small, so that the life of the light source can be extended and its maintenance can be simplified.

Next, FIG. 5 is a diagram showing the main part of a second embodiment of the present invention, in which a red light emitting die with convex brightness set to the same illuminance: t-F1
a, Ib, IC, 1 (light IIk with id & 1,
The red light emitting diodes la, lb of the 211AI and the red light emitting diodes 11c, 1d of the other 211AI are made into a pair and arranged close to the peripheral side corresponding to the peripheral side 1'il+ of the °C barcode 5, There is.、Two、N、One、S、
Label 4I-'s bar 2 l-1, 5's bar is i + "1 crossed A) reading 1'Iit, the surroundings of l- (71 (<, as a result, image I: 7 ri 11 l ni i iHyJr) bar 2 t -1; 04: 0) 11 < 1 degree can be equalized and equalized 4.

In addition, FIG. 6 shows a main part configuration diagram C of the ffi 3 embodiment of the present invention. The deformed semicylindrical shape 1 ((1 bright lens 3Δ) deformed to "(becomes lower)" is disposed. As a result, as in the second embodiment, the barcode 5 is The illuminance around No. 111 of the reading line 1 perpendicular to the bar is high, and the central part is (111) compared to that.
In this case, it is possible to uniformize the illumination 10 of the bar image over the entire area.In this case, 1
It becomes possible to make the light Vθ 11\purely uniform and illuminance.

Furthermore, FIG. 7 is a block diagram of the main part of the fourth embodiment of the present invention, in which each pixel 9a, 9(), . . .
Assuming the shape of -C, its length is compared to the central part and the periphery! 71;
has a shape change that becomes J,L, and even if there is a difference in the amount of light in the image on J,C image module 9, every time you look at its -child, it will start.

In addition, in the embodiment described in 1.1-, the red light emitting diode 1.2
C1 round or square light emitting diode (71-1' complemented by 11A1) Bar code label/l/4, l-10) Bar: Illuminates the entire surface of I-card 5 C may also be used using a surface-emitting type red light emitting diode with RB brightness that can provide -F I II^1.

Further, although a hand-held type reading device is illustrated as the reading position 11y and 'A, it is also possible to apply it to a stationary type reading device in which only the barcode label 4 is moved.

Further, although t11 is shown as optical information that targets the barcode 5, it may also target other codes or characters.

Also, a't I[i! Although a linear image hinge is shown as an example, other sensors such as a planar two-dimensional image sensor may also be used.

Furthermore, the light source is 'CC versus brightness red light emitting diode,
Although the lamp used is shown as an example, other lamps such as a normal tungsten lamp may also be used.

As stated above, the present invention is capable of appropriately converting an image of optical information into an electrical signal by using a scanning type sensor. Furthermore, the illumination light is 1
0) First-order (imaging an elephant) is based on the partial difference in the 911814 system, and 1. The influence of the partial difference in light intensity of the image is
+ can be erased, which has the excellent effect of reducing partial reading failures to 1.

[Brief explanation of drawings]

FIG. 1 shows the first fruit 7Il of the present invention! An 811-minute broken configuration diagram showing one example, Figure 2 is an exploded explanatory diagram of the main part, and Figure 3 is the essential part!
11<Electrical wiring diagram, Figure 4 is by me! 1. Optical characteristic diagram for explanation, No. 5 and 1 is an explanatory diagram of the main part of the second embodiment of the present invention,
FIG. 6 is a main part configuration diagram of the third embodiment of the present invention, and FIG.
FIG. 4 is a configuration diagram of main parts of a fourth embodiment of the present invention. 1.2... Red luminescent Gui J-l package that forms the light source 3...
・11 (1 brightness, 4...label, 5...jt
'l's information+It's bar two t-l', (i...i11 surface reflecting mirror, 7...lens, 8...aperture a++ material,
9...Reading hinge and ゛(no-(mage sensor). 11...1(ri(degree 1 + rectifying circuit.

Claims (1)

[Claims] ((2) illumination light of 1 tl, 1, Equipped with a system of light,
That reading f! An optical information reader that converts the information into an electrical signal. Then, let the sensitivity of photoelectric conversion to the optical information be C1 and its optical ti'/? An optical information reading device characterized in that a correction means is installed to reduce the sensitivity of the periphery compared to the center fill. (2) Patent A'+'' In the optical information reading device according to claim 1, the correction means is arranged such that the correcting means 1(((bright light), Comparison: Illumination around C
1(ri) emitting light 1((((emitting means(il)
(3)Special!'l' It/l Required range lil i? + with positive hand 13hi is t!!I R1
Assuming that 2ib'e is taken, the shape 4 of each 1lIli element and its center f! Compared to the No. 1 pixel, the shape of the pixels in the peripheral area has changed so as to disturb the photoelectric sensitivity. An optical information reading device that reads 'ttr rK'.