Patent Application
20200257870
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2019-022837, filed in Feb. 12, 2019, the entire contents of which are incorporated herein by reference.
An embodiment of the present invention relates to a symbol reading apparatus.
Conventionally, there is a symbol reading apparatus which captures and reads a symbol such as a bar code attached to a commodity sold at a store. The symbol reading apparatus has a window on one side of the housing. An illumination light source such as an LED (Light Emitting Diode) is provided inside the housing and emits light toward the outside of the housing through the window. This light is reflected by the symbol attached to the commodity and received by an imaging unit to read the symbol.
In order to ensure the degree of freedom in the direction in which the symbol is read, a plurality of light sources are often provided in the upper and lower peripheral portions or the left and right peripheral portions of the housing. Typically, the light sources are installed close to the window.
The light emitted from each light source is diffused by a planar diffusion sheet provided on the entire surface of the light source, and is irradiated to a wide range from the window. However, the diffused light emitted from the window may not reach the center portion of the window, because the light source is provided in the peripheral portion and positioned close to the window, and the diffusion sheet is provided between the light source and the window in parallel with the window. Therefore, when a target object having a symbol is held near the center portion of the window, the light may not reach the symbol sufficiently in which case the symbol cannot be read successfully.
According to an embodiment, a symbol reading apparatus for reading a symbol includes a housing having an opening, a transparent window that covers the opening, a light source arranged at a peripheral portion of the inside of the housing and configured to emit light toward the transparent window, a diffusion element arranged between the light source and the transparent window and including a first side and a second side that is opposite to the first side. The first side is closer to the center of the transparent window than the second side but is farther from a surface of the transparent window than the second side along a direction that extends from the light source to the transparent window, and a light receiver by which the light diffused by the diffusion element and reflected by the symbol is received.
Hereinafter, a symbol reading apparatus according to one or more embodiments of the present invention will be described with reference to the accompanying drawings. In the embodiments, diffusion sheets are described as an example of a diffusion material. In addition, in the embodiments, a commodity is described as an example of an object to be read. It should be noted that the present invention is not limited to the embodiments described below.
First, the outline of the symbol reading apparatus will be described. For example, the symbol reading apparatus is embedded into a POS (Point of Sales) terminal installed in a store. The symbol reading apparatus is a device for reading a symbol, such as a bar code or a two dimensional code, which is attached to a commodity, which is purchased by a customer. The symbol reading apparatus receives the reflected light from the symbol and reads the symbol. The POS terminal acquires the commodity specifying information specifying the commodity based on the read symbol, and executes the sales processing of the commodity.
Next, the structure of the symbol reading apparatus will be described.
The symbol reading apparatus 1 comprises diffusion sheets 7 at the upper and lower positions of the window 4, which are front planar portions of the inner portion of the housing 2. Each of the diffusion sheets 7 is, for example, a milky white sheet in which fine particles are scattered and printed on a polyester sheet (e.g., PET (Polyethylene Terephthalate)). The diffusion sheets 7 diffuse the light emitted from a light source of the symbol reading apparatus 1, which is described later.
The symbol reading apparatus 1 also includes a planar mirror 6 which is mounted obliquely within the housing 2. The mirror 6 receives light reflected by a symbol S and incident thereon, and then reflects the light toward an imaging unit, which will be described later.
The symbol reading apparatus 1 comprises a reading lamp 5 on the top surface thereof. The reading lamp 5 emits light when the POS terminal determines that the symbol reading apparatus 1 correctly reads the symbol S so that an operator of the POS terminal can confirm that the reading is successfully done.
Next, the internal structure of the symbol reading apparatus 1 will be described.
The peripheral portion 12 refers to a region near the boundary between the window 4 and the front cover 3, which is the upper or lower side of the symbol reading apparatus 1. In an embodiment, the light emitting unit 8 is provided on each of the upper portion of the housing 2 and the lower portion of the housing 2. The light emitting unit 8 provided on the upper portion of the housing 2 is referred to as a light emitting unit 81. The light emitting unit 8 provided in the lower portion of the housing 2 is referred to as a light emitting unit 82.
The light emitting units 81 and 82 radiate light to the outside of the window 4 from the upper and lower sides of the housing 2, respectively. The diffusion sheets 7 are provided between the window 4 and each of the light emitting units 81 and 82. Each of the diffusion sheets 7 is formed in a shape as shown in
The planar portion 71a is arranged in parallel with the window 4 and the light emitting unit 81. The planar portion 71a extends from a position near the peripheral portion 12 to the extending portion 71e in the downward direction in
The planar portion 71a diffuses light emitted from the light emitting unit 81 toward the window 4. Therefore, the light that has passed through the planar portion 71a is diffused to a wider angle. Further, the bent portion 71b diffuses light emitted from the light emitting unit 81 downward and toward the central portion 4a. Therefore, the light which has passed through the bent portion 71b is also diffused to a wider angle. The light that has passed through the diffusion sheet 7 is diffused in the range 81L, and exits from the window 4.
On the other hand, the light emitting unit 82 radiates light to the outside of the window 4 from the lower side of the housing 2 to the window 4 substantially upward. The diffusion sheet 7 is provided between the window 4 and the light emitting unit 82. The diffusion sheet 7 has the same shape as shown in
The planar portion 72a is arranged in parallel with the window 4 and the light emitting unit 82. The planar portion 72a extends from a position near the peripheral portion 12 to the extending portion 72e in the upward direction in
The planar portion 72a diffuses light emitted from the light emitting unit 82 toward the window 4. Therefore, the light that has passed through the planar portion 72a is diffused to a wider angle. Further, the bent portion 72b diffuses light emitted from the light emitting unit 82 downward and toward the central portion 4a. Therefore, the light that has passed through the bent portion 72b is also diffused to a wider angle. The light that has passed through the diffusion sheet 7 is diffused in the range 82L, and exits from the window 4.
Then, the range 81L and the range 82L include the central portion 4a, i.e., the lights emitted from light emitting units 81 and 82 are diffused by the diffusion sheets 7 and reach the central portion 4a sufficiently. That is, the light emitted from the light emitting unit 8 is diffused by the diffusion sheets 7 to reach the central portion 4a sufficiently.
The symbol reading apparatus 1 comprises the mirror 6. The mirror 6 is inclined in an oblique direction with respect to the housing 2. The mirror 6 reflects light reflected by the symbol S toward the imaging unit 9 by approximately 90 degrees.
The symbol reading apparatus 1 also includes an imaging unit 9 within the housing 2. The imaging unit 9 has a planar CMOS (complementary metal-oxide semiconductor) image sensor, for example. The imaging unit 9 receives the light reflected by the mirror 6. The imaging unit 9 reads the symbol S by receiving the reflected light.
The light emitted from the light emitting unit 8 is diffused by the diffusion sheets 7. The light diffused by the diffusion sheets 7 is emitted from the window 4, and reflected by the symbol S. The reflected light L2 is incident on the symbol reading apparatus 1 through window 4. The incident light is reflected by the mirror 6, and imaged by the imaging unit 9.
The light emitted from the light emitting unit 8 is diffused by the diffusion sheets 7 to reach the central portion 4a of the window 4. For this reason, even if the commodity M is held very close to the window 4, the light reaches the symbol S. Therefore, even when the commodity M is brought close to the central portion 4a of the window 4, the symbol S can be read.
The shape of the diffusion sheets 7 shown in
By arranging the diffusion sheets 7 as described above, the light emitted from the light emitting unit 8 is diffused by the diffusion sheets 7, and reaches the central portion 4a of the window 4 sufficiently. For this reason, even if the commodity M is held very close to the window 4, the light reaches the symbol S. Therefore, the symbol S can be read even in the case where the commodity M is placed close to the central portion 4a of the window.
Further, as shown in
By arranging the diffusion sheets 7 having such a shape, the light emitted from the light emitting unit 8 is diffused by the diffusion sheets 7, and reaches the central portion 4a of the window 4. For this reason, even if the commodity M is held very close to the window 4, the light reaches the symbol S. Therefore, the symbol S can be read even in the case where the commodity M is placed close to the central portion 4a of the window 4.
According to such an embodiment, light emitted from the light emitting unit 8 is diffused by the diffusion sheet 7 that extends from one end of the light emitting unit 8 to the peripheral portion 12 such that one end of the diffusion sheet 7 is closer to the peripheral portion 12 than the other end on the peripheral portion 4. Therefore, the symbol S can be read even if the commodity M is brought close to the central portion 4a of the window 4.
For example, in the embodiments, the light emitting unit 8 and the diffusion sheets 7 are provided at the upper and lower positions of the peripheral portion 12. However, the present invention is not limited thereto, and the light emitting unit 8 and diffusion sheets 7 may be provided in the left and right positions of the peripheral portion 12, for example.
In addition, in the embodiments, two light emitting units 8 are provided vertically. However, the present invention is not limited thereto, and the light emitting unit 8 may be provided at any one of the upper, lower, left and right sides of the peripheral portion 12. Further, the light emitting unit 8 may be provided at three or more of the upper, lower, left and right sides of the peripheral portion 12.
In addition, in the embodiments, the diffusion sheets 7 are described as an example of an element to diffuse light emitted from the light emitting unit 8. However, the present invention is not limited thereto, and any material may be used as long as the light emitted from the light emitting unit 8 is diffused to a wide range.
In addition, in the embodiments, the peripheral portion 12 is described as being provided on the upper side and the lower side of the symbol reading apparatus 1. However, the peripheral portion 12 may be provided on the left side and the right side of the symbol reading apparatus 1.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-022837 | Feb 2019 | JP | national |
