JPH0575701U - Optical transmitter array - Google Patents

Abstract

(57) [Summary] [Objective] To obtain an optical transmission medium array with high light utilization efficiency of a light source, capable of accommodating high-speed image reading ability, and having less unevenness of light amount. An optical transmission element array in which a cylindrical lens portion is provided on at least one of both side surfaces of a parallel array, the optical transmission elements having a rectangular parallelepiped shape and a refractive index distribution that approximates a quadratic curve only in the thickness direction. [Advantages] By adjusting the length in the z-axis direction, the area of the contact surface with the light source can be extremely widened, and the utilization efficiency of the light source can be improved. In addition, the unevenness of the amount of light existing in the cylindrical light transmitting element array can be almost suppressed. Moreover, since it has a rectangular parallelepiped shape, the arrangement is very easy.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an optical transmitter array that can be effectively used as a dry copying machine, an LED printer, an image reading sensor for a facsimile.

[0002]

[Prior Art]

 As an image reading sensor for dry copiers and facsimiles, a large number of cylindrical lens elements having a continuous refractive index distribution from the center to the outer periphery are arranged in parallel, and this lens element array is bonded and sandwiched by two substrates. The optical transmitter array that is worn is effectively used. With the demand for miniaturization, high functionality, and high speed of copying machines, LED printers, facsimiles, etc., the light transmission array is downsized and the image reading performance is improved. Improvement is required. At present, an optical sensor unit using an LED light source, a lens array and a light receiving element array as shown in FIG. 1 is being used.

[0003]

[Problems to be solved by the device]

 In FIG. 1, reference numeral 1 denotes an optical transmission medium array. This optical transmission medium array has a lens element array in which a large number of gradient index cylindrical lens elements 2 are arranged in parallel and is sandwiched between two substrates 3 and 4. It has a structure. The cylindrical lens element 2 has a diameter of about 1 mm. The optical axis of the rod-shaped lens element in this optical transmission element array is aligned with the sensor 6 in order to accurately read the transmission image from the image plane 5. The light source 7 is composed of LEDs, and the angle θ formed by the optical axis 8 of the rod-shaped lens element and the optical axis 9 of the LED is usually 45 degrees, and the light emitted from the LED light source is Since the utilization factor of the amount of light reflected by 5 and captured by the rod-shaped lens element is extremely small, the sensitivity of the optical transmission element array is not always good.

Further, since the radius of the cylindrical lens element is about 1 mm, the light quantity utilization factor is further reduced. For this reason, efforts have been made to increase the radius of the optical transmission medium to improve the amount of light, but it is very difficult to form the desired refractive index distribution of the optical transmission medium. Furthermore, in the columnar optical transmitter array, there was unevenness in the amount of light due to the arrangement of the columnar objects.

[0005]

[Means for Solving the Problems]

 The present inventors have completed the present invention as a result of studying to solve the above-mentioned problems, and the gist of the present invention is the distribution of the refractive index having a rectangular parallelepiped shape having the x-axis, the y-axis, and the Z-axis. -Type optical transmission medium having a refractive index distribution approximately similar to the refractive index distribution curve defined by [Equation 1] from the center surface to the side surface in the thickness (x-axis) direction of the optical transmission material. An optical transmitter array is characterized in that a cylindrical lens portion having a generatrix parallel to the arrangement direction of the optical transmitter array is provided on at least one surface on both sides of the parallel array of transmitters.

[Equation 1]

In the optical transmission medium array of the present invention, the lens element is composed of a rectangular parallelepiped array as shown by 21 in FIG. 2, and the light quantity which is a problem when using the conventional optical transmission medium array. It is effective in solving the low utilization rate, and has almost no light unevenness generated in the columnar optical waveguide array. Further, in the rectangular parallelepiped optical transmission body used in the present invention, it is desirable that the portions other than the light input / output surface are blackened in order to block light leakage and extra light from the outside.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 2 is a perspective view showing an outline of the optical transmission device array of the present invention. In the figure, reference numeral 21 is a rectangular parallelepiped optical transmission body having a refractive index distribution only in the thickness direction (x-axis direction), and 22 is a cylindrical lens. Light enters from the direction A.

FIG. 3 is an enlarged view of a rectangular parallelepiped gradient index optical transmission body having an x axis, ay axis and az axis, but there is no refractive index distribution in the z direction and the y direction, and Only has a quadratic curve-shaped refractive index distribution.

FIG. 4 is a cross-sectional view showing the optical characteristics in the zy plane of the optical transmission element array of the present invention, in which light is focused by the cylindrical lens portion 42. FIG. 5 is a plan view showing the optical characteristics in the xy plane of the optical transmission medium array of the present invention. Since the refractive index distribution of the rectangular parallelepiped optical transmission medium 51 is only in the x-axis direction, The light beam is bent and the light is focused. For this reason, this optical transmitter array has the same optical characteristics as the gradient index cylindrical lens array used conventionally. Further, in the optical transmitter array of the present invention, since the length in the z direction can be determined by the curvature of the cylindrical lens, the lens area can be greatly expanded, and the light quantity utilization efficiency can be greatly improved. It is very effective for speeding up and downsizing copiers, facsimiles, and LED printers.

FIG. 6 is a cross-sectional view showing the optical characteristics of the zy plane of another example of the optical transmission element array of the present invention. In this example, a cylindrical lens 62 is attached to one end surface of the optical transmission element array 61. Is. The image A forms an erect image at B. FIG. 7 is a cross-sectional view of the optical transmitter array shown in FIG. 6 along the xy plane, showing the optical characteristics within this plane. Reference numeral 71 is an optical transmitter array, and 72 is a cylindrical lens. Image A forms an upright image B.

FIG. 8C shows a rectangular parallelepiped type having an x-axis, a y-axis, and a z-axis, and a cylindrical lens section 82 is integrally formed on both end faces of an optical transmission element array section 81 having a refractive index distribution only in the x-axis direction. 1 is a perspective view of a formed optical transmission device array of the present invention. As shown in FIG. 7A, this optical transmitter array has an x-axis, a y-axis, and a z-axis, and has a refractive index distribution only in the x-axis direction. The optical transmission element array element 84 shown in (b) is cut out, and the array element is laminated as shown in FIG.

The refractive index distribution type lens original body having a refractive index distribution only in the x-axis direction used for carrying out the present invention is made of glass containing alkali metal ions to form a rectangular parallelepiped shape as shown in FIG. Then, this rectangular parallelepiped was immersed in a mixed metal salt of Te ₂ SO ₄ −R ₂ SO ₄ (R represents a metal other than Te), alkali ions were treated by the ion exchange method, and the bending ratio in the x-axis direction was measured. A rectangular parallelepiped as shown in Fig. 7 (a) is made with a method of using a distribution standard or a mixture of fluorinated alkyl methacrylate polymer and methyl methacrylate, and methyl methacrylate is partially evaporated from the side surface of this rectangular parallelepiped. A method of polymerizing methyl methacrylate by providing a refractive index distribution in the x-axis direction, or preparing multiple polymer / monomer mixed liquids with different refractive indexes, and decreasing the refractive index sequentially from the center plane to both sides. It can be produced by stacking the above layers, subjecting the monomers in each layer to mutual diffusion treatment to provide a refractive index distribution in the x-axis direction, and polymerizing each monomer.

Since the optical transmission medium array of the present invention uses a rectangular parallelepiped having a refractive index distribution only in the x-axis direction as the gradient index lens element and is configured in combination with a cylindrical lens, the optical transmission medium has a cylindrical shape. Unlike the above, no optical space was created between the array of optical transmitters, and it was possible to obtain an optical transmitter array without unevenness of the light quantity.

[0014]

[Submission date] December 28, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

FIG. 6 is a cross-sectional view showing the optical characteristics of the zy plane of another example of the optical transmission element array of the present invention. In this example, a cylindrical lens 62 is attached to one end surface of the optical transmission element array 61. It is a thing. The image A forms an inverted image at B. FIG. 7 is a cross-sectional view of the xy plane of the optical transmission medium array shown in FIG. 6, showing the optical characteristics in this plane. Reference numeral 71 is an optical transmission element array, and 72 is a cylindrical lens. The image A is formed as an inverted image B 2.

[Brief description of drawings]

FIG. 1 is a schematic view of an image reading unit incorporating a gradient index columnar optical transmission medium array.

FIG. 2 is a perspective view showing an example of an optical transmission element array of the present invention.

FIG. 3 is a master plate for making an optical transmission medium array.

FIG. 4 is a diagram showing optical characteristics of the optical transmission element array of the present invention.

FIG. 5 is a diagram showing optical characteristics of the optical transmission device array of the present invention.

FIG. 6 is a diagram showing optical characteristics of the optical transmission element array of the present invention.

FIG. 7 is a diagram showing optical characteristics of the optical transmission device array of the present invention.

FIG. 8 is a view showing a method of assembling another example of the optical transmission element array of the present invention.

[Explanation of symbols]

1 …………………… Light transmitter array 2 …………………… Cylindrical light transmitter 3, 4 ……………… Substrate 5 …………………… Image plane 6 ………… ………… Light receiving element 7 …………………… Light emitting element 21,41,51,61,71,81 ………………… Rectangular parallel-refractive index distribution type optical transmitter 22,42,52,62 , 72, 82 ……………………… Cylindrical lens 83 ………………… Original plate for making optical transmitter 84 ………………… Array element for optical transmitter

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[Procedure amendment]

[Submission date] April 21, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Number 1] ^{_{n (a) = n o {}} 1- (g 2/2) a 2} wherein, _{n o} is the refractive index of the central surface portion of the optical transmission _{body, n (a)}
Is the refractive index at the position of a toward the outside from the center plane of the light transmission body, g is the refractive index distribution constant, and a is the distance from the center plane of the light transmission body to the outside.

Claims (1)

[Scope of utility model registration request] 1. A gradient index optical transmission body having a rectangular parallelepiped shape having an x-axis, a y-axis and a z-axis, wherein a direction from the center plane to the side surface in the thickness direction (x-axis direction) of the optical transmission body is [ [1] A cylindrical structure having a generatrix parallel to the arrangement direction of the optical transmission medium array on both side surfaces of the parallel array of the refractive index distribution type optical transmission medium having a refractive index distribution approximately similar to the refractive index distribution curve An optical transmission element array comprising a lens portion. [Equation 1]