JPH05103154A - Optical reader - Google Patents

Abstract

PURPOSE:To provide the optical reader which is easy to be assembled from its optical parts and easy to be aligned and it is possible to be miniaturize and to make thin in thickness and to be reduced in cost with regard to the optical reader which utilizes neural net function to read original character and graphic. CONSTITUTION:A light source 1, a reflecting type collimator lens 3, a reflecting type lens array 4 and a spatial light modulating element 7 are arranged on the surface of a transparent substrate 2. Further, an photodetector array 5 is provided on the spatial light modulating element 7. Reflected and scattered light is introduced into the transparent substrate 2 and transferred in zigzag. Then it is made incident on the collimator lens 3 and lens eye 4, and then it is imaged on the photodetector 5 through the spatial light modulating element 7, thus the signal of the medium 9 to be read, is read.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reading optical apparatus having a function of a neural network for reading characters, figures and tables of a reading medium such as a manuscript with error correction, and in particular, it can be made thin. Further, the present invention relates to a reading optical device in which it is easy to assemble and position each optical component.

[0002]

2. Description of the Related Art Optical devices for reading characters and images are used in facsimiles, copying machines, etc., but recently,
Optical reading devices have been developed that are capable of optically reading even faint characters and handwritten characters other than printed characters by providing an artificial brain (AI) / neural network function.

A conventional reading optical device having a function of a neural network is shown in FIG. 4 (Hamachu et al., Microoptics News, Vol. 9,).
No. 2, pp. 59-64, 1991). The light output from the surface light source 17 is applied to the liquid crystal display plate 12 which is a reading medium, and the transmitted light from the display plate 12 is incident on the rod lens which is the collimator lens 13 and is displayed through the lens array 14. Characters or figures on the plate 12 are multiply developed by the number of lens elements of the lens array 14, pass through the transmissive spatial light modulator 15, are imaged on the photodetector array 16, and are read out. Is. At this time, unclear characters, figures, handwritten characters, and the like can be read while being corrected by the function of the neural network by making the transmittance distribution of the spatial light modulator 15 appropriate.

[0004]

In the conventional reading optical device shown in FIG. 4, alignment of each optical component during assembly is troublesome, and a bulk lens array 14 or rod lens 13 is used. Therefore, there is a problem that it is difficult to reduce the size, weight and cost.

The present invention has been made in view of the above problems, and provides a reading optical device in which the position of each optical component can be easily adjusted, and the thickness and cost can be reduced.

[0006]

A light source, a transparent substrate, a reflective collimator lens and a reflective lens array formed on the front surface or the back surface of the transparent substrate, a spatial light modulator, and a photodetector array. , The light from the light source, irradiating a reading medium, the reflected scattered light from the reading medium is guided as a propagating light in the transparent substrate, the propagating light is propagated in a zigzag shape in the substrate, The reflection type collimator lens, the reflection type lens array, the spatial light modulator, and the photodetector array are sequentially guided.

[0007]

According to the above construction, the optical path of the optical system, which has been set in the free space in the conventional reading optical apparatus, is set in the substrate in which the light propagates in a zigzag shape by utilizing the reflection of the boundary surface. Since the components can be installed on one substrate, the reading optical device of the present invention can easily perform optical alignment, and can be reduced in size, thickness and cost.

[0008]

1 (a) and 1 (b) are a plan view and a sectional view, respectively, showing the basic construction of a reading optical apparatus according to an embodiment of the present invention. In the plan view of FIG. 1A, the light absorption layer 8a formed on the uppermost part is removed for the sake of clarity. 2 is a cross-sectional view (a) and a plan view (b) of a reflective collimator lens constituting the reading optical device according to the embodiment of the present invention, and FIG. 3 is a diagram showing the reading optical device according to the embodiment of the present invention. It is a top view of the reflective lens array which does. A reading optical device according to an embodiment of the present invention will be described in detail with reference to FIGS. 1, 2, and 3.

In the figure, the transparent substrate 2 has, for example, a thickness (size in the Z direction) of 1 mm and a width (size in the X direction) of 15 m.
A glass substrate having m and a length (size in the Y direction) of 30 mm, and a light source 1, for example, an LED array is provided on the transparent substrate 2. Illumination light 10 emitted from the light source 1 and having a wavelength of 0.5 μm, for example, is applied to the document as the reading medium 9. A part of the light reflected and scattered from the reading medium 9 enters the transparent substrate 2 and, for example, the propagation angle θ = 30.
Propagation light 11 in the vicinity of (propagation angle: angle formed by the optical axis of the propagation light: the vertical (Z) direction) is formed, and a metal layer such as Ag, Al, or Au provided on the surface of the transparent substrate 2 or a dielectric The reflective layers 6d, 6b, 6e, 6c, 6 which are reflected on the reflective layer 6a, which is a multilayer film, are similarly provided on the back and front surfaces of the substrate 2.
The light is incident and reflected in a zigzag shape in order on f, and is provided on the surface of the substrate 2, for example, a focal length of 8.7 mm and a Y-direction size of 2 m.
It is incident on the reflective collimator lens 3 of m and further reflected by the reflective layer 6g, and for example, one lens element has a size in the Y direction of 100 μm and a focal length of 2.3 mm. 2 is incident on the reflective lens array 4 provided on the surface thereof, further propagates in a zigzag manner, and is sequentially incident on the spatial light modulation element 7 formed on the transparent substrate 2 and the photodetector array 5 formed on the element 7. Then, it is converted into an electric signal and the information on the reading medium 9 is read. At this time, by appropriately setting the transmittance distribution of the spatial light modulator 7, the information of the medium 9 can be corrected and read using the function of the neural network.

In this embodiment, the reflective layer 6 is centered on a point in the vicinity where the optical axis of the propagating light 11 intersects (reflects) the substrate 2.
The rectangular substrate was provided on the front and back surfaces of the transparent substrate 2 in an island shape by the number of reflections. The size of the island-shaped reflective layer 6 is the same as or smaller than that of the reflective collimator lens 3. By doing so, since a gap is formed between the reflection layers 6, the propagating light 11 near the set propagation angle can be propagated most strongly, and the propagating light that becomes crosstalk and becomes a noise component is zigzag. The light passes through between the reflection layers 6 while propagating, and is reduced by being absorbed by the light absorption means 8a, 8b formed on the reflection layer 6 which is an organic film such as polyimide containing a dye or a pigment. This has the effect of improving the SN ratio of the detector array 5. However, even if the reflecting layer 6 on either the front surface or the back surface of the substrate 2 is formed in an island shape, the effect is reduced by half but the operation is possible.

In this embodiment, the optical path length from the reading medium 9 to the reflection type collimator lens 3 is set to the focal length f of the collimator lens 3, and the optical path length from the lens array 4 to the spatial light modulator 7 is set. , The focal length f ₁ of the lens array 4 was set. The ratio of the image sizes of the reading medium 9 formed by the lens array 4 on the photodetector array 5 by the number of lenses is f ₁ / f. In this embodiment, the image ratio is 0.26, for example. However, the ratio can be increased or decreased by adjusting each focal length, and the pattern shape size of the spatial light modulator 7 and the device size of the photodetector array 5 are determined according to the ratio.

The reflective collimator lens 3 and the reflective lens array 4 are reflective diffractive optical elements composed of a plurality of grating zones 18 having a maximum groove depth of 0.19 μm and a reflective layer 19, for example. By using such a diffractive optical element, the film thickness is at most 1 μm or less, and since it can be integrated on the transparent substrate 2, it can be made much smaller, thinner and stable.

By arranging the light source 1, the spatial light modulator 7, the photodetector 5, and the optical elements 3 and 4 on the front surface of the substrate 2, the back surface having the reading medium 9 can be made almost flat. .. Further, even if the reading medium 9 comes into contact with the back surface of the substrate 2, since the components are on the front surface, there is almost no fear of damage and the environmental resistance is improved.

As shown in FIG. 2, the lens elements constituting the reflective lens 3 and the reflective lens array 4 of this embodiment are composed of a plurality of grating zones 18 and the reflection zones provided on the grating zones 18. Each grating zone 18 is made of a layer 19 and has an elliptical shape with the same eccentricity with a major axis in the Y-axis direction, which is the optical axis direction of the propagating light 11b, and the period becomes smaller toward the outer circumference. The ratio of the major axis to the minor axis of the ellipse (major axis / minor axis) is 1 / cos θ (θ: the propagation angle of the above-mentioned propagating light), and the center position of the ellipse further increases toward the outer periphery of the above-mentioned grating zone. ,
It is gradually shifted in one major axis direction of the ellipse (Y direction in the collimator lens 3 and -Y direction in the lenses forming the lens array 4). By using a lens having such a shape, aberrations caused by the influence of oblique incidence were almost eliminated (completely aberration-free on the optical axis), and good image formation was possible. Further, as shown in FIG. 3, in the reflective lens array 4, the pattern shape of the grating zone 18 of the one lens element is the same as that of the reflective collimator lens 3, but the lens aperture is a rectangular aperture, and the lens element is Since the array structure is formed in close contact with no gap between the lenses and the dead space between the lenses can be eliminated, the light can be effectively used.

The lens 3 and the lens array 4 have a saw-toothed cross section for high efficiency. The optical elements 3 and 4 of the master are
For example, an electron beam resist such as PMMA or CMS is coated on another substrate, an electron beam drawing method is performed to control the irradiation amount according to the film thickness of a device to be manufactured, and a development process is performed to adjust the resist film thickness. It was formed by changing. From the thus formed optical element (master), a mold including the optical elements 3 and 4 at the same time is manufactured by, for example, a nickel electroforming method, and the same lens element as that of the master is formed on the transparent substrate 2 by using, for example, a UV curing resin. 3, 4 were duplicated. According to this method, the diffractive optical elements of the lens 3 and the lens array 4 can be easily formed on the transparent substrate 2 with high positional accuracy, and at the same time, the cost can be reduced. After the replication, the reflection layer 19 was formed by depositing a metal layer of Ag, Al, Au, or the like on the reflection layer 19.

The photodetector array 5 is, for example, CdS-Cd.
Using Se thin film, one opening size 100 × 100μ
For example, 15 × 15 is integrated on the spatial light modulator 7 at m ² . A-Si may be used instead of CdS-CdSe, and, for example, a bulk Si photodetector may be installed on the substrate 2 without being integrated, but it becomes thin when integrated. , Stabilization can be realized.

As the spatial light modulator 7, a silver salt dry plate having a transmittance distribution is used. In this embodiment, the reflective layer 6 is formed on the transparent substrate 2 to reflect the propagating light 11. However, zigzag propagation is also possible using total internal reflection within the substrate 2. At this time, it is not necessary to form the reflective layer 6, but it is necessary to provide a grating or a prism at the incident portion of the reflected and scattered light from the reading medium 9 into the substrate 2.

[0018]

As described above, according to the present invention, the alignment of each optical component can be easily performed and the thickness can be reduced, and a reading optical device using a neural network function can be realized.

[Brief description of drawings]

FIG. 1A is a plan view showing the basic configuration of a reading optical apparatus according to an embodiment of the present invention, and FIG. 1B is a sectional view showing the basic configuration of the reading optical apparatus.

FIG. 2A is a cross-sectional view of a reflective collimator lens used in a reading optical device according to an embodiment of the present invention, and FIG. 2B is a plan view of the reflective collimator lens.

FIG. 3 is a plan view of a reflective lens array of a reading optical device according to an embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional reading optical device.

[Explanation of symbols]

 1 Light Source 2 Transparent Substrate 3 Reflective Collimator Lens 4 Reflective Lens Array 5 Photodetector Array 6 Reflective Layer 7 Spatial Light Modulator 8 Light Absorbing Layer 9 Reading Medium 10 Illuminating Light 11 Propagating Light 18 Grating Zone 19 Reflective Layer

Claims (8)

[Claims] 1. A light source, a transparent substrate, a reflective collimator lens and a reflective lens array formed on the front or back surface of the transparent substrate, a spatial light modulator, and a photodetector array. Of the reading medium, the reflected and scattered light from the reading medium is guided as propagating light in the transparent substrate, the propagating light is propagated in a zigzag manner in the substrate, and the reflective collimator lens is used. ,
A reading optical device, which is configured to sequentially lead to the reflective lens array, the spatial light modulator, and the photodetector array. 2. The reading optical device according to claim 1, wherein a reflective layer is provided on the front surface and the back surface of the transparent substrate. 3. At least one of the reflection layers provided on the front surface or the back surface of the transparent substrate is provided in a plurality of islands on the optical path of the propagating light, and the size of the island reflection layers is a reflection type collimator lens. 3. The reading optical device according to claim 2, wherein the position is equal to or less than that, and the position where the island-shaped reflective layer is provided is near the intersection of the optical axis of the propagating light and the substrate surface. .. 4. A reflection type collimator lens and a reflection type lens array are composed of a plurality of grating zones and a reflection layer provided on the grating zones, and the pattern shape of the grating zones is long in the optical axis direction of propagating light. The ellipse has an axis, the ratio of the long axis to the short axis (long axis / short axis) is 1 / cos θ (θ: propagation angle of the propagation light), and the center position of the ellipse is the grating. The reading optical device according to claim 1, wherein the reading optical device is gradually shifted in one major axis direction of the elliptical shape toward the outer peripheral portion of the zone. 5. A lens according to claim 1, wherein one lens constituting the reflective lens array has a rectangular aperture, and the lenses having the rectangular aperture are arranged without a gap to constitute the lens array. Reading optics. 6. The reading optical apparatus according to claim 3, wherein light absorbing means is provided at least between the reflecting layers. 7. The reading optical apparatus according to claim 6, wherein the light absorbing means is an organic film containing a dye or a pigment. 8. The reading optical apparatus according to claim 1, wherein a spatial light modulator is provided on the front or back surface of the transparent substrate, and a photodetector array is provided on the spatial light modulator.