JP2018132701A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly irradiate the whole of imaging range of an imaging unit with illumination light even when an illumination light source is arranged on one side of the imaging unit.SOLUTION: An information reader 100 includes: an imaging unit 10 for capturing an image in an imaging range; and an illumination unit 30 arranged on one side of the imaging unit 10 in a direction perpendicular to an optical axis of the imaging unit 10, to project light emitted from a light source to the imaging range, via an illumination lens 301. The illumination lens 301 includes a reflector surface 360 formed on a side face between a lens surface 350a and a lens surface 350b to reflect light so as to irradiate an end of the imaging range with the light. The reflector surface 360 is formed of multiple facing pairs. In each of the pairs, an angle formed by a first reflector surface far from the imaging unit 10 and an imaging surface of the imaging unit 10 is larger than an angle formed by a second reflector surface close to the imaging unit 10 and the imaging surface.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an information reading apparatus.

  In an information reading unit (for example, a barcode reader) that reads a code symbol such as a barcode or a two-dimensional code, an imaging unit (imaging sensor and imaging lens) is provided at the center of the casing of the information reading device, and both sides of the imaging unit There has been proposed a configuration in which an LED (Light Emitting Diode) for illumination is provided (see, for example, Patent Document 1). With this configuration, it is possible to irradiate illumination light symmetrically with respect to the imaging optical axis in the imaging range (field-of-view range) of the imaging unit. However, the configuration in which the LEDs for illumination are provided on both sides of the imaging unit cannot realize downsizing of the information reading apparatus. On the other hand, Patent Document 2 discloses a configuration in which one LED for illumination is provided on one side of an imaging unit in an information reading device (see, for example, Patent Document 2).

U.S. Pat. No. 8,910,782 U.S. Pat. No. 9212380

  However, as in Patent Document 2, in the configuration in which the illumination light source (LED) is provided on one side of the imaging unit, it is particularly difficult to secure a sufficient amount of light in the peripheral part of the angle of view. There is a problem that illumination light cannot be uniformly irradiated over the entire range.

  An object of the present invention is to provide an information reading apparatus capable of uniformly irradiating illumination light over the entire imaging range of an imaging unit even in a configuration in which an illumination light source is provided on one side of the imaging unit.

  An information reading apparatus according to an aspect of the present invention is provided on an imaging lens that captures an image within an imaging range, and is disposed on either side of the imaging unit in a direction orthogonal to the optical axis of the imaging unit. An illumination unit that projects light emitted from a light source onto the imaging range, and the illumination lens includes a first lens surface on which the light is incident and a second lens on which the light is emitted. A reflector surface that is formed on a lens surface and a side surface between the first lens surface and the second lens surface and reflects the light so that the light is applied to an end of the imaging range; The reflector surface is formed of a plurality of pairs facing each other, and in each pair, the angle formed by the first reflector surface far from the imaging unit and the imaging surface of the imaging unit is close to the imaging unit The second reflector surface and the imaging surface are formed Greater than the degree.

  An information reading apparatus according to an aspect of the present invention is provided on an imaging lens that captures an image within an imaging range, and is disposed on either side of the imaging unit in a direction orthogonal to the optical axis of the imaging unit. An illumination unit that projects light emitted from a light source to the imaging range, and the illumination lens is a cylinder or an elliptical column, and the first lens surface on which the light is incident; and The light is formed on a second lens surface from which light is emitted and a side surface between the first lens surface and the second lens surface, and the light is applied to an end of the imaging range. An angle formed between the first busbar farthest from the imaging unit and the imaging plane of the imaging unit on the reflector surface is the second busbar closest to the imaging unit and the reflector surface. It is larger than the angle formed by the imaging surface.

  According to the present invention, even in a configuration in which the illumination light source is provided on one side of the imaging unit, it is possible to uniformly irradiate illumination light over the entire imaging range of the imaging unit.

The perspective view which shows an example of the external appearance of a reader Block diagram showing the configuration of the reader The perspective view which shows an example of the external appearance of an illumination lens The figure which shows the relationship between the incident angle and the reflection angle on the reflector surface The figure which shows the relationship between the imaging range in a reader, and the irradiation range of illumination light The figure which shows the structural example of the illumination lens in a view angle longitudinal direction The figure which shows the structural example of the illumination lens in a field angle short side direction The figure used for explanation of the positional relationship between the illumination light source and the illumination lens

  Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[Configuration of Reader]
FIG. 1 is a perspective view showing an example of an appearance of an information reading apparatus 1 (hereinafter simply referred to as “reading apparatus”) according to the present embodiment. FIG. 2 is a block diagram showing a configuration of the reading apparatus 1 according to the present embodiment.

  1 and 2, the reading device 1 includes an imaging unit 10, an aiming unit 20, an illumination unit 30, a control unit 40 (not shown in FIG. 1), and a housing 50. For example, the reading device 1 captures a code symbol on the reading target by the imaging unit 10 to generate image data, and analyzes the image data to read the code symbol (information) on the reading target object.

  In the following description, the x-axis direction is the “field angle longitudinal direction” in the imaging range (view angle range) of the imaging unit 10, and the y-axis direction is the “field angle short direction” in the imaging range of the imaging unit 10. To do. That is, in the following description, the imaging range is a rectangle with the x-axis direction as the long direction and the y-axis direction as the short direction. Note that the imaging range of the imaging unit 10 is not limited to a rectangle, but may be other shapes.

  The housing 50 accommodates at least the imaging unit 10, the aiming unit 20, the illumination unit 30, and the control unit 40.

  The imaging unit 10 captures an image within the imaging range. The imaging unit 10 includes an imaging lens 101 and an imaging sensor 102.

  The imaging lens 101 is an optical system for forming an image of reflected light from the imaging target on the imaging sensor 102. The imaging lens 101 may be composed of a single lens or a plurality of lenses. Further, the imaging lens 101 may be a lens whose focus can be adjusted.

  The imaging sensor 102 captures an image of the imaging target formed by the imaging lens 101. For example, the imaging sensor 102 is configured by a CMOS (complementary metal oxide semiconductor) image sensor or the like, and takes an image of an imaging target by converting an optical signal into an electrical signal. The imaging sensor 102 outputs image data of the captured image to the control unit 40.

  The aiming unit 20 projects aiming light for forming a mark indicating the standard of the imaging range that can be imaged by the imaging unit 10 on the imaging object.

  The illumination unit 30 projects illumination light onto the imaging range captured by the imaging unit 10. As shown in FIG. 1, the illumination unit 30 is arranged on one side (left side in FIG. 1) of the imaging unit 10 in a direction (x-axis direction in FIG. 1) orthogonal to the imaging optical axis (z-axis direction) of the imaging unit 10. Has been. Note that the position where the illumination unit 30 is disposed is not limited to the position illustrated in FIG. 1. For example, the illumination unit 30 may be disposed on the right side of the imaging unit 10 in FIG. 1.

  The illumination unit 30 includes an illumination lens 301 and an illumination light source 302.

  The illumination lens 301 constitutes an optical system for projecting light emitted from the illumination light source 302 to the outside as illumination light. The illumination lens 301 is configured to uniformly illuminate the entire imaging range of the imaging unit 10 with illumination light. The illumination lens 301 may be, for example, a resin lens such as acrylic or may be formed of other materials. The detailed configuration of the illumination lens 301 will be described later.

  The illumination light source 302 is, for example, an LED, and is a light source that emits light that is projected onto the imaging range of the imaging unit 10 as illumination light. The illumination light source 302 is not limited to an LED.

  The control unit 40 controls the imaging performed in the imaging unit 10, controls the decoding of image data output from the imaging unit 10, aiming control performed in the aiming unit 20, and illumination light performed in the illumination unit 30. Controls the light emission process.

  The functional blocks of the control unit 40 and the like in the reading device 1 are, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores data such as programs executed by the CPU or various tables, and various CPUs. It may be realized by a RAM (Random Access Memory) used as a work area when executing the process. The CPU controls the operation of the entire reading device 100. As the CPU, ROM, and RAM, for example, an ASIC (Application Specific Integrated Circuit), a flash ROM (FROM), an SDRAM (Synchronous Dynamic Random Access Memory), or the like may be used. The ASIC may be realized by a combination of a CPU and an LSI such as an FPGA (Field Programmable Gate Array).

  Further, the reading device 1 may further include a communication interface for performing communication with an external device of the reading device 1.

[Configuration of Illumination Lens 301]
FIG. 3 is a perspective view showing an example of the appearance of the illumination lens 301 provided in the reading device 1 shown in FIG.

  The illumination lens 301 shown in FIG. 3 is disposed on the lens surface 350a (bottom surface in FIG. 3) on which light emitted from the illumination light source 302 enters and on the opposite side of the lens surface 350a, and the lens from which the illumination light is emitted to the outside. A surface 350b (upper surface in FIG. 3) is provided. Each of the lens surface 350a and the lens surface 350b may have a predetermined curvature.

  The illumination lens 301 shown in FIG. 3 includes four reflector surfaces 360a, 360b, 360c, and 360d that are formed on the side surface between the lens surface 350a and the lens surface 350b and reflect light incident from the lens surface 350a. Prepare. The reflector surface 360 may be a flat surface or a curved line to disperse or concentrate light.

  In the illumination lens 301 shown in FIG. 3, the reflector surface 360 a and the reflector surface 360 b are opposed to each other in the x-axis direction (that is, the width direction of the reading device 1 in FIG. 1) that is the longitudinal direction of the field angle. In the y-axis direction that is the hand direction (that is, the height direction of the reading device 1 in FIG. 1), the reflector surface 360c and the reflector surface 360d face each other. That is, the four reflector surfaces 360 shown in FIG. 3 are formed from a plurality of pairs facing each other.

  Further, the illumination lens 301 shown in FIG. 3 may include an attachment portion 370 for attaching the illumination lens 301 to the housing 50 shown in FIG.

  The reflector surface 360 of the illumination lens 301 reflects the light so that the light emitted from the illumination light source 302 is irradiated to the end of the imaging range of the imaging unit 10 (that is, the periphery of the angle of view). Hereinafter, the structure which projects illumination light in the illumination part 30 is demonstrated concretely.

  First, the configuration of the illumination unit 30 in the view angle longitudinal direction (x-axis direction) will be described.

  In the reading apparatus 1 shown in FIG. 1, the reflector surface 360a is a reflector surface close to the imaging unit 10 (imaging lens 101) in the two reflector surfaces 360a and 360b facing each other in the x-axis direction that is the longitudinal direction of the field angle. The reflector surface 360b is a reflector surface far from the imaging unit 10.

  FIG. 4 is a diagram illustrating a state of light reflected by each reflector surface 360. In FIG. 4, the refractive index of the illumination lens 301 is n, and the refractive index of air is 1.

When the incident angle θ ₁ and the refractive index n are in the relationship of the following expression (1), the light is totally reflected at the reflector surface 360.
sin θ ₁ = 1 / n (1)

Further, when the light is totally reflected by the reflector surface 360, the relationship of incident angle θ ₁ = exit angle θ ₂ is established. As an example, when the illumination lens 301 is made of acrylic resin, n = 1.49, and the total reflection angle θ ₁ = 42.15 °.

For example, in the illumination unit 30, the incident angle θ ₁ or the material (refractive index n) of the illumination lens 301 may be set so that the light emitted from the illumination light source 302 is totally reflected on the reflector surface 360. Further, the outer wall of the illumination lens 301 (that is, the reflector surface 360) may be transparent, and may be painted white or silver so that light is reliably totally reflected.

Next, FIG. 5 illustrates an imaging range of the imaging unit 10 in the reading device 1 when viewed from the upper surface of the reading device 1 illustrated in FIG. 1 (that is, a direction facing the reflector surface 360c illustrated in FIG. 3), and an illumination unit. It is an example which shows the relationship with the range irradiated with 30 illumination light. In FIG. 5, the imaging range of the imaging unit 10 is an area between the straight line 101a and the straight line 101b. In FIG. 5, as an example, the imaging range A at a position that is a predetermined distance away from the reading device 1 in the direction of the imaging optical axis (hereinafter also referred to as “z ₁₀ ”) of the imaging unit 10 will be described.

As shown in FIG. 5, the optical axis of the illumination unit 30 (illumination lens 301, illumination light source 302) (hereinafter also referred to as “z ₃₀ ”) is deviated from the imaging optical axis z ₁₀ in the x-axis. Installed in position. Therefore, in the longitudinal direction of the field angle (x-axis), the distance between the left end portion (peripheral portion of the straight line 101a) of the imaging range A shown in FIG. 5 and the illumination unit 30 is the right end portion (straight line) of the imaging range A shown in FIG. 101b (peripheral part) and the distance of the illumination part 30. That is, if around the optical axis z ₃₀ of the illumination unit 30, the imaging range A shown in FIG. 5 are asymmetric on the x-axis.

The positional relationship between the illumination unit 30 and the both ends of the imaging range A shown in FIG. 5 differs according to the difference (deviation) between the imaging optical axis z ₁₀ and the optical axis z ₃₀ .

Therefore, in the present embodiment, the imaging optical axis z ₁₀ and the optical axis z ₃₀ in the longitudinal direction of the angle of view are set so that the light reflected by each reflector surface 360 is irradiated to the end of the imaging range of the imaging unit 10. The angle between each reflector surface 360 and the imaging surface of the imaging unit 10 (in this case, parallel to the x axis) is determined in accordance with the difference (displacement).

  FIG. 6 is an enlarged view of the illumination unit 30 (the illumination lens 301 and the illumination light source 302) illustrated in FIG. 5, and is a diagram illustrating a state of light passing through the illumination lens 301. FIG. 6 shows the state of light reflected by each reflector surface 360, and omits the state of light emitted from the lens surface 350b without being reflected by each reflector surface 360.

Specifically, in FIG. 6, the angle φ _a between the reflector surface 360 a and the imaging surface (x axis) of the imaging unit 10 is the reflector surface with respect to the optical axis z _{30 in} the imaging range of the imaging unit 10. It is determined that the light (illumination light 301a) reflected by the reflector surface 360a is projected at the end of the region opposite to 360a (around the right end (straight line 101b) of the imaging range A shown in FIG. 5). .

Similarly, in FIG. 6, the angle φ _b between the reflector surface 360 _b and the imaging surface (x axis) of the imaging unit 10 is the same as that of the reflector surface 360 _b with respect to the optical axis z _{30 in} the imaging range of the imaging unit 10. It is determined that the light (illumination light 301b) reflected by the reflector surface 360b is projected onto the end of the opposite region (around the left end (straight line 101a) of the imaging range A shown in FIG. 5).

As shown in FIG. 5, the left end portion of the imaging range A is farther than the right end portion of the imaging range A with respect to the illumination unit 30 (optical axis z ₃₀ ) in the longitudinal direction of the view angle. For this reason, the projection range of the illumination light 301b projected from the illumination unit 30 to the left end (imaging unit 10) side of the imaging range A is the right end of the imaging range A from the illumination unit 30 (opposite to the imaging unit 10). It is necessary to make it wider than the projection range of the illumination light 301a projected to the side.

Accordingly, in FIG. 6, the angle φ _b (that is, the spread angle on the side opposite to the imaging unit 10) is larger than the angle φ _a (that is, the spread angle on the imaging unit 10 side). That is, φ _a <φ _b . Thereby, for example, when light having the same angle as the optical axis z ₃₀ shown in FIG. 6 is incident on the reflector surfaces 360a and 360b, φ _a is larger than φ _b , so The incident angle θ ₁ (reflecting reflection angle θ ₂ ) of the incident light is smaller than the incident angle θ ₁ (reflecting reflection angle θ ₂ ) of the light incident on the reflector surface 360a. Therefore, in the longitudinal direction of the angle of view, the projection range of the illumination light 301b is wider than the projection range of the illumination light 301a.

  As a result, as shown in FIG. 5, the illumination light 301a (solid line) reflected by the reflector surface 360a is projected around the right end of the imaging range A, and the illumination light (dotted line) reflected by the reflector surface 360b. Is projected to the periphery of the left end portion, which is farther from the right end portion of the imaging range A, from the illumination unit 30.

As described above, the angles φ _a and φ _b in the reflector surfaces 360a and 360b are determined according to the positional relationship between the illumination unit 30 (optical axis z ₃₀ ) and the imaging unit 10 (optical axis z ₁₀ ).

In other words, the four reflector surfaces 360 forming the illumination lens 301 include a pair of reflector surfaces 360a and 360b that face each other in the longitudinal direction of the field angle. Then, the pair of reflector surfaces 360a and reflector surface 360b, the angle phi _b formed between the imaging surface of the reflector surface 360b and the imaging unit 10 away from the imaging unit 10, formed by the reflector surface 360a and the imaging surface is close to the imaging unit 10 It is larger than the angle φ _b.

  By doing so, as shown in FIG. 5, the illumination unit 30 has the reflector surfaces 360a and 360b in the vicinity of both field angles (near the straight line 101a and the straight line 101b) in the imaging range A in the longitudinal direction of the field angle. The illumination light reflected by the can be projected.

  Next, the configuration of the illumination unit 30 in the short field angle direction (y-axis direction) will be described.

  FIG. 7 shows the state of illumination light projected through the illumination lens 301 in the illumination unit 30 when viewed from the side surface of the reading device 1 shown in FIG. 1 (the direction facing the reflector surface 360a shown in FIG. 3). FIG. FIG. 7 shows the state of the light reflected by each reflector surface 360, and omits the state of the light emitted from the lens surface 350b without being reflected by each reflector surface 360.

As in the longitudinal direction of the angle of view (see, for example, FIGS. 4 and 5), the angle of view is short so that the light reflected by the reflector surfaces 360c and 360d is irradiated to the end of the imaging range of the imaging unit 10. The angle between each reflector surface 360 and the imaging surface of the imaging unit 10 (parallel to the x-axis here) is determined in accordance with the difference (deviation) between the imaging optical axis z ₁₀ and the optical axis z ₃₀ in the direction. .

Specifically, in FIG. 7, the angle φ _c between the reflector surface 360 c and the imaging surface (y axis) of the imaging unit 10 is the reflector surface with respect to the optical axis z _{30 in} the imaging range of the imaging unit 10. It is determined so that light (illumination light 301c) reflected by the reflector surface 360c is projected onto the end of the region opposite to 360c (around the lower end of the imaging range; not shown).

Similarly, in FIG. 7, the angle φ _d between the reflector surface 360 d and the imaging surface (y axis) of the imaging unit 10 is the same as that of the reflector surface 360 d with respect to the optical axis z _{30 in} the imaging range of the imaging unit 10. It is determined so that light (illumination light 301d) reflected by the reflector surface 360d is projected onto the end of the opposite region (around the upper end of the imaging range, not shown).

For example, when the optical axis z ₁₀ and the optical axis z ₃₀ are in the same direction in the short angle of view (y-axis direction), the angle φ _d shown in FIG. 7 (that is, the spread angle on the opposite side to the imaging unit 10). And the angle φ _c (that is, the spread angle on the imaging unit 10 side) may be made substantially the same. On the other hand, when the optical axis z ₁₀ is present on the reflector surface 360 c side with respect to the optical axis z _{30 in the} shorter field angle direction (y-axis direction), the angle φ _d shown in FIG. The spread angle) may be larger than the angle φ _c (that is, the spread angle on the imaging unit 10 side).

As described above, even in the short angle of view, the angles φ _c and φ at the reflector surfaces 360c and 360d are determined according to the positional relationship between the illumination unit 30 (optical axis z ₃₀ ) and the imaging unit 10 (optical axis z ₁₀ ). Each _d is determined.

  In other words, the four reflector surfaces 360 forming the illumination lens 301 include a pair of a reflector surface 360c and a reflector surface 360d that are opposed to each other in the short angle of view. In the pair of the reflector surface 360c and the reflector surface 360d, the angle φ formed by one reflector surface 360 far from the imaging unit 10 and the imaging surface of the imaging unit 10 is equal to the other reflector surface 360 and the imaging surface near the imaging unit 10. It becomes larger than the angle φ formed by.

  By doing so, the illumination unit 30 can project the illumination light reflected by the reflector surfaces 360c and 360d in the vicinity of the angle of view of both the imaging range of the imaging unit 10 in the short angle of view.

  The configuration of the illumination lens 301 has been described above.

  As described above, in the reading device 1 in which the illumination unit 30 is arranged on one side of the imaging unit 10, the illumination lens 301 includes the lens surface 350a on which light emitted from the illumination light source 302 is incident and the lens surface on which light is emitted. 350b and a reflector surface 360 that is formed on the side surface between the lens surface 350a and the lens surface 350b and reflects the light so that the light is applied to the end of the imaging range of the imaging unit 10.

  Here, as shown in FIG. 8, generally, when only the lens surface is used, the distance (referred to as L1) between the illumination lens and the illumination light source in the optical axis direction (z-axis direction) of the illumination unit. The light condensing property can be improved by increasing the length, but the amount of light that is not incident on the illumination lens from the illumination light source increases as the distance L1 increases. Further, in order to prevent an increase in light not incident on the irradiation lens, as shown in FIG. 8, the width (referred to as L2) of the illumination lens in a direction (y-axis direction) perpendicular to the optical axis direction of the illumination unit is also used. It needs to be wide. That is, in order to project illumination light over the entire imaging plane using only the lens surface, the size of the illumination unit becomes large. On the other hand, when the distance L1 is short, the amount of light around the angle of view of the imaging range decreases due to aberrations in light collection.

  On the other hand, in the present embodiment, the illumination unit 30 has an imaging range in which the amount of light is reduced only by illumination light that is not reflected by the reflector surface 360 of the illumination lens 301 but is collected by the lens surfaces 350a and 350b. The illumination light reflected by the reflector surface 360 is additionally projected onto the end portion (around the angle of view). That is, the illumination unit 30 irradiates the entire imaging range of the imaging unit 10 with illumination light by projecting illumination light over the entire imaging range using both the lens effect and the reflector effect of the single illumination lens 301. can do.

  Therefore, according to the present embodiment, even in the configuration in which the illumination unit 30 (illumination light source 302) is provided on one side of the imaging unit 10, the entire imaging range of the imaging unit 10 can be irradiated with illumination light uniformly.

  Further, in the present embodiment, even when the distance L1 is short (that is, when the amount of light around the angle of view decreases when the light is collected by the lens surface 350), the illumination unit 30 is compared with the case where only the lens surface is used. Thus, it is not necessary to increase the width L2 of the illumination lens 301. Therefore, according to the present embodiment, the illumination lens 301 can be reduced in size and cost.

  Further, according to the present embodiment, the illuminating unit 30 reflects the light reflected by the reflector surface 360 with respect to the optical axis of the illumination light source 302 in the imaging range in the optical axis direction of the imaging unit 10. The light is projected to a region opposite to the reflector surface 360 (diagonal). Thereby, in order to project illumination light to the end of the imaging range, the angle φ of the reflector surface 360 with respect to the imaging surface can be set larger, so that the shape (width) of the illumination lens 301 increases. Thus, the illumination lens 301 can be reduced in size and cost.

(Other embodiments)
(1) In the above embodiment, the case where the inclination of the reflector surface 360 (φ _a , φ _b shown in FIG. 6) is set has been described, but the illuminating unit 30 of the reading device 1 uses the optical axis z of the imaging unit 10 ₁₀ and the inclination of the lens surface 350 (curvature) may be set according to the difference (deviation) between the optical axis z ₃₀ of the illumination unit 30. Thereby, illumination light can be efficiently irradiated to the entire imaging range of the imaging lens 101.

  (2) In the above embodiment, the light reflected from the reflector surface 360 is on the imaging optical axis of the imaging unit 10 on the opposite side of the reflector surface with respect to the optical axis of the illumination light source 302 in the imaging range Although the case where light is projected onto the (corner) area has been described, the present invention is not limited to this. For example, even if the light reflected from the reflector surface 360 is projected to the region on the same side as the reflector surface with respect to the optical axis of the illumination light source 302 in the imaging optical axis of the imaging unit 10 in the imaging range. Good.

  (3) Although the case where the illumination lens 301 is formed with the four reflector surfaces 360a to 360d has been described in the above embodiment, the illumination lens 301 may include more reflector surfaces 360 than the four surfaces. . Thereby, the illumination part 30 can perform the projection of the illumination light to the imaging range by the light reflected by the reflector surface 360 with high accuracy in more directions.

  (4) The shape of the illumination lens 301 is not limited to the quadrangular prism as shown in FIG. 3, and may be a polygonal prism other than the quadrangular prism. That is, the illumination lens 301 should just be a polygonal column provided with the reflector surface 360 which has a mutually opposing pair like the reflector surface 360a and the reflector surface 360b shown in FIG.

  (5) The shape of the illumination lens 301 (reflector) is not limited to the prism as shown in FIG. 3, and may be a cylinder or an elliptical cylinder.

  When the illumination lens 301 is a cylinder or an elliptic cylinder, the illumination lens 301 has a lens surface on which light emitted from the illumination light source 302 is incident, a lens surface on which illumination light is emitted to the outside, and a side surface between the two lens surfaces. And a reflector surface that reflects the light so that the light is applied to the end of the imaging range. Further, on the reflector surface, the angle formed by the bus farthest from the imaging unit 10 and the imaging surface of the imaging unit 10 is larger than the angle formed by the bus nearest to the imaging unit 10 and the imaging surface of the imaging unit 10. Designed.

  By doing this, the illumination unit 30 projects the illumination light reflected by the reflector surface in the vicinity of both field angles of the imaging range of the imaging unit 10 as in the above embodiment (when the illumination lens 301 is a prism). Can be light.

  The present invention is useful for a system for optically reading information.

DESCRIPTION OF SYMBOLS 1 Information reader 10 Imaging part 20 Aiming part 30 Illumination part 40 Control part 50 Case 101 Imaging lens 102 Imaging sensor 301 Illumination lens 302 Illumination light source 350 Lens surface 360 Reflector surface 370 Attachment part

Claims (4)

An imaging unit that captures an image within an imaging range;
An illumination unit that is disposed on either side of the imaging unit in a direction orthogonal to the optical axis of the imaging unit and projects light emitted from a light source to the imaging range via an illumination lens;
Comprising
The illumination lens is
A first lens surface on which the light is incident;
A second lens surface from which the light exits;
A reflector surface that is formed on a side surface between the first lens surface and the second lens surface and reflects the light so that the light is applied to an end of the imaging range;
The reflector surface is formed from a plurality of pairs facing each other,
In each pair, the angle formed by the first reflector surface far from the imaging unit and the imaging surface of the imaging unit is larger than the angle formed by the second reflector surface close to the imaging unit and the imaging surface.
Information reader. An imaging unit that captures an image within an imaging range;
An illumination unit that is disposed on either side of the imaging unit in a direction orthogonal to the optical axis of the imaging unit and projects light emitted from a light source to the imaging range via an illumination lens;
Comprising
The illumination lens is a cylinder or an elliptic cylinder,
A first lens surface on which the light is incident;
A second lens surface from which the light exits;
A reflector surface that is formed on a side surface between the first lens surface and the second lens surface and reflects the light so that the light is applied to an end of the imaging range;
In the reflector surface, the angle formed by the first bus bar farthest from the imaging unit and the imaging surface of the imaging unit is larger than the angle formed by the second bus bar closest to the imaging unit and the imaging surface,
Information reader. The illumination unit projects the light reflected by the reflector surface to a region on the opposite side of the reflector surface with respect to the optical axis of the light source in the imaging range in the optical axis direction of the imaging unit. ,
The information reading apparatus according to claim 1. The color of the reflector surface is transparent, white or silver,
The information reading apparatus according to claim 1.

Images