JPH063593A - Optical reflecting element - Google Patents

Abstract

PURPOSE:To reflect all incident light beams by forming an optical reflecting element of a transparent material having a reflecting surface obtained by rotating a curved line having a focus around an axis and an incidence surface obtained by rotating an arc drawn around the focus as a center around an axis. CONSTITUTION:A 1st bowl-shaped reflecting full-length mirror 50 which has a light transmission hole 50a in its center inner bottom part is sectioned in a parabolic surface shape and a concave mirror whose internal surface is a mirror surface. When an optical transmitter is placed at a distance, this concave mirror 50 reflects and converges incident lights L1, L2... which are nearly parallel to the axis Z on the focus P1. An optical reflecting element 51 formed of transparent glass or synthetic resin as a 2nd reflecting mirror consists of a circular external surface part 52, a curved surface part 53, and a body part 54. Then the circular external surface part 52 is in the shape obtained by rotating the arc which contains the focus P1 of the concave mirror 50 in its center around the axis Z. Light beams traveling to the focus P1 from the outside of the circular external surface part 52 are made to travel straight at the incidence point on the circular external surface part 52.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical reflecting element,
For example, the present invention relates to an optical reflection element included in a photoelectric conversion device used for an airborne transmission device using light, a POS (position operation system), an optical communication between a personal computer and a printer, and the like.

[0002]

2. Description of the Related Art There are various types of photoelectric conversion devices used for optical transmission by air, and one example is shown in FIG. Reference numeral ₁ is a concave mirror having a parabolic cross section defined by a cross section of y ² = 4P ₁ x, and its inner surface is a reflecting surface. This concave mirror 1 has an incident light L ₁ when the optical transmitter is distant,
L ₂ ··· is substantially parallel to the axis Z and is focused on the focal point P ₁ . Further, a transparent hole 1a is formed in the central bottom portion of the concave mirror 1.

2 has a cross section of y²= 4P₂defined by x
A small-diameter convex mirror with a parabolic cross section, with the outer surface as the reflecting surface.
There is. This convex mirror 2 is the same as the concave mirror 1 whose mirror surface side is described above.
Focus P on the transparent hole 1a ₂Is the focus P of the concave mirror 1₁When
They are arranged so that they are at the same position.

Lights L ₁ , L _2, ... From the optical transmitter that have entered the concave mirror 1 are reflected by the concave mirror 1 and condensed, and then reflected by the convex mirror 2 and reflected light thereof. Becomes light parallel to the axis Z.

That is, in FIG. 7, assuming that the light La is emitted from the focus P ₂ on the axis Z, it is reflected at the point T of the convex mirror 2 in parallel with the axis Z and becomes the light of Lb. If the tangent line at the point T of the convex mirror 2 is S, then Q ₁ = Q ₂ . Assuming that the light of Lc goes to P ₂ , Q ₁ =
Since it is Q ₃ , if the reflected light of the light Lc is Ld, then Q ₃ = Q
_{Is 4} .

From this, Q ₂ = Q _{4 and} Ld becomes light parallel to the axis Z. Therefore, the light reflected by the convex mirror 2 becomes parallel to the axis Z and goes out of the concave mirror 1 through the light transmitting hole 1 a of the concave mirror 1.

A light receiving element 3 is provided outside the concave mirror 1. The light receiving element 3 is provided on the reflection optical path of the convex mirror 2 and is provided with the axis Z as the center position.

As a result, the light is reflected by the convex mirror 2 and the transparent hole 1
Light emitted from a to the outside of the concave mirror 1 is incident on the light receiving surface of the light receiving element 3 and photoelectrically converted. The above-mentioned light receiving element 3 is an electronic circuit component 4 for impedance conversion or another electronic circuit component 5
It is also provided on the circuit board 6.

In the photoelectric conversion device described above, when the optical transmitter is located relatively far away, the emitted light becomes substantially parallel to the axis Z and enters the concave mirror 1. The incident lights L ₁ , L _2, ... Are reflected on the inner surface of the concave mirror 1 to form a focal point P _1.
Head to. Reflected lights L ₁ and L _{2 which} are directed to the focal point P ₁ ...
.. is reflected by the outer surface of the convex mirror 2 and becomes light parallel to the axis Z and goes out of the concave mirror 1 through the light transmitting hole 1a. Then, the light L ₁ , L _2, ... Collected as described above is received by the light receiving element 3, and the optical signal is converted into an electric signal and sent to the signal output circuit.

When the optical transmitter is located at a short distance, the position of the optical transmitter is set to the first focus F ₁ as shown in FIG.
The light L ₁ , L _2, ... Is reflected by using the concave mirror 7 having an elliptic curve cross section with the second focus being F ₂ . The concave mirror 7 is also provided with a light transmitting hole 7a in the central bottom portion.

Reflected lights L ₁ , L ₂ ... Reflected by the concave mirror 7
.. is reflected by the convex mirror 2 having the focal point P ₂ provided at the same position as the focal point F ₂ of the concave mirror 7, emitted from the light transmitting hole 7 a as reflected light parallel to the axis Z, and provided on the reflected optical path of the convex mirror 2. It is incident on the light receiving element 3 and photoelectrically converted.

[0012]

Since the photoelectric conversion device described above has a configuration in which the convex mirror 2 is arranged in the concave mirror 1, a supporting means for the convex mirror 2 is required. Must be constructed so as not to block the light L ₁ , L ₂ ,.

Therefore, the optical reflecting element as shown in FIG. 9A is used as the convex mirror 2. The optical reflection element 8 is made of a transparent synthetic resin, and a curved concave surface 8b is formed at the front end of a body portion 8a having a circular cross section, and a light receiving element 9 is embedded in the rear portion thereof.

The curved concave surface 8b is a curved reflecting surface obtained by rotating a parabola having a focal point P ₂ around the axis Z, and the light receiving element 9 is located in the optical path of the light reflected by this reflecting surface. ing.

The above-mentioned optical reflecting element 8 is inserted through the light transmitting hole 1a of the concave mirror 1 and the terminal pins 9a, 9 of the light receiving element 9 are inserted.
It is attached so that b is fixed to the circuit board 6. In this case, the focal point P ₂ of the curved concave surface 8b is made to coincide with the focal point P _{1 of the} concave mirror 1.

In the photoelectric conversion device configured as described above, the light reflected by the concave mirror 1 enters from the barrel portion 8a of the optical reflection element 8, is reflected by the curved concave surface 8b, and is received by the light receiving element 9.

However, in the above-described optical reflection element 8, the reflected light from the concave mirror 1 is incident on the optical reflection element 8 at different incident angles because the body portion 8a forming the incident surface has a circular cross section. Then, the light is refracted according to each incident angle.

That is, since the light reflected by the concave mirror 1 does not go to the focal point P ₂ , the light reflected by the curved concave surface 8b does not become parallel to the axis Z, and the amount of light received by the light receiving element 9 decreases.

In view of the above situation, it is an object of the present invention to develop an optical reflection element which is used in the above photoelectric conversion device or the like to reflect all incident light.

[0020]

In order to achieve the above object, in the present invention, as a first invention, a reflecting surface obtained by axially rotating a curve having a focal point and an optical path of light directed to the focal point. Then, an optical reflection element is proposed which is made of a transparent material having an incident surface obtained by rotating an arc drawn around the focal point.

As a second invention, in the optical reflection element of the first invention, an optical reflection element characterized in that a light receiving element located in the reflection optical path of the reflection surface is embedded and integrally fixed. Suggest a device.

Further, as a third invention, an optical reflecting element of the first invention is characterized in that the reflecting surface is formed as a mirror surface.

[0023]

In the optical reflection element of the first invention, all the incident light is incident from the incident surface at the same incident angle, so that there is no refraction of the light and all the incident light goes to the focal point. As a result, all the incident light is reflected by the reflecting surface in a certain direction.

In the optical reflecting element in which the light receiving element is embedded and integrally fixed, the light reflected by the reflecting surface as described above is received by the light receiving element and photoelectrically converted. Further, if the reflecting surface is formed as a mirror surface, the shape of the reflecting surface of the optical reflecting element is not specified and the degree of freedom in forming the reflecting surface is widened.

[0025]

EXAMPLES Next, examples in which the present invention is used as an optical reflection element of a photoelectric conversion device will be described with reference to the drawings. FIG. 1 is a principle block diagram of a photoelectric conversion device showing a first embodiment of the present invention.

Reference numeral 50 denotes a bowl-shaped first reflecting mirror having a light transmitting hole 50a in the center bottom thereof. The reflecting mirror 50 has a cross-sectional shape of y.
^{In the} parabolic cross section defined by ² = 4P ₁ x, the inner surface is a concave mirror with a mirror surface. This concave mirror 50 has an incident light L ₁ that is substantially parallel to the axis Z when the optical transmitter is distant,
L ₂ is reflected and focused on the focal point P ₁ .

Reference numeral 51 denotes an optical reflecting element formed of transparent glass or synthetic resin material, which serves as a second reflecting mirror. The optical reflection element 51 includes a circular outer surface portion 52, a curved surface portion 53, and a body portion 54.
Has a shape obtained by rotating an arc around the focal point P ₁ of the concave mirror 50 around the axis Z, and the circular outer surface portion 5
Light traveling from the outside of 2 to the focal point P ₁ travels straight at the incident point of the circular outer surface portion 52.

The curved surface portion 53 has an optical reflection element 51.
Is curved according to a parabola defined by y ² = 4P ₂ x. Further, the body portion 54 has a circular cross section so that it can be inserted into the light transmitting hole 50 a of the concave mirror 50.

As shown in FIG. 1, the optical reflecting element 51 has a light receiving element 55 embedded therein in advance, and the terminal pin 5 of the light receiving element 55 protruding from the back surface of the optical reflecting element 51.
6 is fixedly held on the circuit board 57.

The optical reflecting element 51 has a curved surface portion 53.
The focal point P ₂ of the concave mirror 50 is aligned with the focal point P _{1 of the} concave mirror 50. Further, the light receiving element 55 is provided with the axis Z on the reflection optical path of the curved surface portion 53 in the optical reflecting element 51.
Is buried so that the center position is. Further, the terminal pin 56 is connected to a signal circuit provided on the circuit board 57.

In the photoelectric conversion device constructed as described above, when the optical transmitter is located relatively far, the transmitted light is incident on the concave mirror 50 as light substantially parallel to the axis Z. The incident lights L ₁ , L _2, ... Are reflected on the inner surface of the concave mirror 50 and travel toward the focal point P ₁ .

The reflected light L ₁ towards the focal point P _1, L ₂ ···
.. is incident from the circular outer surface portion 52 of the optical reflection element 51,
The circular outer surface portion 52 goes straight and enters the curved surface portion 53. Then, the light is reflected again by the curved surface portion 53 to become light parallel to the axis Z and the light receiving element 5 provided in the optical reflecting element 51.
The light signal is returned to an electric signal by the light receiving element 55 and is sent to a signal output circuit provided on the circuit board 57.

In the photoelectric conversion device described above, all the lights L ₁ , L _2, ... Reflected by the concave mirror 50 are incident from the circular outer surface portion 52 of the optical reflection element 51 at the same incident angle. This light is not refracted, is reflected in the same direction by the curved surface portion 53, and is sent to the light receiving element 55.

The photoelectric conversion device has an optical reflection element 51.
Since the terminal pin 56 of the light receiving element 55 provided in the above is fixed to a predetermined position of the circuit board 57 to be held, the holding structure of the optical reflecting element 51 is simplified.

FIG. 2 is a principle block diagram of a photoelectric conversion device showing a second embodiment of the present invention. This embodiment shows the case where the optical transmitter is at a relatively short distance, and the light L ₁ from the optical transmitter is
The first reflecting mirror that reflects L ₂ ... Is a concave mirror 59 having an elliptic curve section, and the curved surface portion 62 of the optical reflecting element 60 is a convex mirror having an elliptic curve section. The concave mirror 59 is provided with a light transmitting hole 59a at the center bottom.

The optical reflecting element 60 which serves as the second reflecting mirror is
The circular outer surface portion 61 has a shape obtained by rotating an arc around the focal point F _{3 of the} concave mirror 59 around the axis Z, and the curved surface portion 62 provided by being curved has an elliptic curve along the axis Z.
The shape is obtained by rotating around. And
The same position as the focus F _{3 of the} concave mirror 59 is the first focus F ₄ , and the center position of the light receiving surface of the light receiving element 63 is the second focus F ₅ . Further, the body portion 64 is the optical reflection element 51 shown in the first embodiment.
The diameter is smaller than that of the body portion 54.

In this optical reflecting element 60, a light receiving element 63 is embedded in the reflected light path of the curved surface portion 62, and this light receiving element 63 is provided.
The terminal pins 65 are fixedly held on the circuit board 66.

[0038] If the optical transmitter is a short distance as the focal point F _6, the light L ₁ by the concave mirror 59 to focus _{F 6, F 3, L 2} ··
.. is reflected. The light reflected by the concave mirror 59 enters the circular outer surface portion 61 of the optical reflection element 60, and the circular outer surface portion 6
1 goes straight on and enters the curved surface portion 62. Then, the light is reflected again by the curved surface portion 62, enters the light receiving element 63, and is photoelectrically converted by the light receiving element 63. In this example,
The light reflected by the curved surface portion 62 is not parallel to the axis Z,
Focus on the focal point F ₅ .

With this structure, the same effect as that of the first embodiment described above can be obtained, and the light receiving surface of the light receiving element 63 can be reduced.

In the above-described first and second embodiments, the curved surface portions 53 and 62 of the optical reflection elements 51 and 60 are silver-plated, and the curved surface portions 53 and 62 are bonded with a mirror-finished metal plate. By forming a mirror surface, it is possible to guide the reflected light to the light receiving elements 55 and 63 by totally reflecting the curved surface portions 53 and 62 without necessarily having a parabolic cross section or an elliptic curve cross section.

Further, in the first and second embodiments,
Although the light receiving elements 55 and 63 are embedded in the optical reflecting elements 51 and 60, as shown in FIG.
It is also possible to dispose 5, 63 outside the optical reflecting elements 51, 60 or to fix them to the outer surfaces of the optical reflecting elements 51, 60.

When the structure shown in FIG. 3 is used,
The body 54 of the optical reflecting element 51 and the light transmitting hole 50 of the concave mirror 50.
It is also possible to form a body having substantially the same diameter as a and inserting the body portion 54 into the light transmitting hole 50a so that the optical reflection element 51 is held by the concave mirror 50.

FIG. 4 is a principle block diagram of a photoelectric conversion device showing a third embodiment of the present invention. 67 is a light-transmitting hole 6 at the center bottom
7a is a bowl-shaped first concave mirror, and the concave mirror 67 is a parabolic mirror whose cross-sectional shape is defined by y ² = 4P ₃ x, and the inner surface of which is mirror-formed.

The concave mirror 67 has a parabolic cross section whose focal point P ₃ is a point distant from the axis Z by a certain distance, and has an annular condensing portion obtained by rotating the focal point P ₃ about the axis Z. Incident lights L ₁ , L _2, ... Which are parallel to the axis Z when the optical transmitter is distant are reflected by the concave mirror 67 and condensed on the condensing portion.

Reference numeral 68 denotes an optical reflecting element provided as a second reflecting mirror. The optical reflecting element 68 is a focal point P of the concave mirror 67.
_A toroidal circular outer surface portion 69 obtained by rotating an arc centered at ₃ about the axis Z, and the concave mirror 67 described above.
The curved surface portion 70 having a shape obtained by rotating a parabola having the focal point F _{7 at the} same position as the focal point P ₃ of the optical axis around the axis Z, and the body portion 7 formed to be inserted into the light transmitting hole 67 a of the concave mirror 67.
1 and 1. Incidentally, this optical reflection element 68
Is made of a transparent material such as glass or a synthetic resin material.

The light receiving element 72 is embedded in the optical reflecting element 68, and the terminal pin 73 of the light receiving element 72 is fixed to the circuit board 74 so that the optical reflecting element 68 is held on the circuit board 74. The optical reflecting element 68 is positioned in the concave mirror 67 so that the focal point F ₇ is aligned with the focal point P _{3 of} the concave mirror 67. Further, the light receiving element 72 is embedded in the optical reflecting element 68 with the axis Z as the center position on the reflected light path of the curved surface portion 70.

In the photoelectric conversion device described above, when the optical transmitter is located relatively far away, the transmitted light becomes the light L ₁ , L ₂ ... Which is substantially parallel to the axis Z and the concave mirror 67. Incident on. The incident lights L ₁ , L _2, ... Are reflected on the inner surface of the concave mirror 67 and travel toward the focal point P ₃ .

The reflected light L ₁ towards the focal point P _3, L ₂ ···
.. is incident on the circular outer surface portion 69 of the optical reflection element 68, goes straight on the circular outer surface portion 69, and is incident on the curved surface portion 70.
Then, the light is reflected again by the curved surface portion 70, becomes light parallel to the axis Z, enters the light receiving element 72, and is photoelectrically converted.
This photoelectric conversion device also has the same effects as those of the first embodiment described above.

FIG. 5 is a principle block diagram of a photoelectric conversion device showing a fourth embodiment of the present invention. This embodiment shows a case where the optical transmitter is at a relatively short distance. The first reflecting mirror is a concave mirror 75 having an elliptic curve cross section, and the curved surface portion 78 of the optical reflecting element 76 is an elliptic curved surface. is there.

The concave mirror 75 has a sectional shape obtained by rotating an elliptic curve having the focal points F ₈ and F ₉ around the axis Z. A transparent hole 75a is formed in the central bottom of the concave mirror 75.
Is provided.

The optical reflecting element 76 which serves as the second reflecting mirror is
The circular outer surface portion 77 has a shape obtained by rotating an arc centering on the focal point F ₉ of the concave mirror 75, which is separated from the axis Z by a certain distance, about the axis Z, and the curved surface portion 78 forms a focal point F _{9 of the} concave mirror 75. An elliptic curve having the same position as the first focal point F ₁₀ and the light receiving surface center of the light receiving element 79 described later as the second focal point F ₁₁ has a sectional shape obtained by rotating around the axis Z. Further, the body portion 80 is formed so that it can be inserted into the light transmitting hole 75a of the concave mirror 75, and is formed so as to have a smaller diameter toward the outside of the light transmitting hole 75a.

Similar to the second embodiment, the optical reflecting element 76 is also made of a transparent material such as glass or synthetic resin, and a light receiving element 79 having a small light receiving surface is embedded and the terminal pin 81 of the light receiving element 79 is embedded. It is fixed to the circuit board 82.

The optical reflecting element 76 has a curved surface portion 78.
Inside the concave mirror 75, its focal point F ₁₀ is
Position and fix so as to match the focal point F ₉ of 5,
Further, the light receiving element 79 is embedded in the optical reflecting element 76 with the axis Z as the center position on the reflected light path of the curved surface portion 78.

[0054] If the optical transmitter is a short distance as the focal point F _8, the light L ₁ by the concave mirror 75 to focus _{F 8, F 9, L 2} ··
.. is reflected. Reflected light L ₁ and L _{2 from the} concave mirror 75
Is incident on the circular outer surface portion 77 of the optical reflection element 76, goes straight on the circular outer surface portion 77, and is incident on the curved surface portion 78. Then, the curved surface portion 78 is reflected again to receive the light receiving element 7.
It is incident on 9 and is photoelectrically converted by the light receiving element 79.

In this case, the light reflected by the curved surface portion 78 is not parallel to the axis Z and is focused on the focal point F ₁₁ . Also in the case of this embodiment, the same effect as that of the above-described second embodiment can be obtained.

In the third and fourth embodiments described above, the curved surface portions 70 and 78 of the optical reflecting elements 68 and 76 are vapor-deposited with silver, or the curved surface portions 70 and 78 are attached with mirror-finished metal plates. When the mirror surface is formed, the reflected light can be guided to the light receiving elements 72 and 79 by totally reflecting the curved surface portions 70 and 78 without necessarily having a parabolic cross section or an elliptic curve cross section.

In the third and fourth embodiments, the light receiving elements 72 and 79 are embedded in the optical reflecting elements 68 and 76. However, the light receiving elements 72 and 79 are included in the optical reflecting elements 68 and 7.
It is also possible to dispose it on the outer side of 6, or to fix it to the outer surfaces of the optical reflection elements 68 and 76.

In this case, the body portions 71 and 80 of the optical reflecting elements 68 and 76 and the light transmitting holes 67a and 75 of the concave mirrors 67 and 75, respectively.
a is formed to have substantially the same diameter, and the body portions 71 and 80 are formed in the light transmitting hole 6
It can be held by being attached to 7a and 75a.

Although the embodiments of the present invention have been described above, the curved surface portion of the optical reflecting element provided as the first reflecting mirror and the second reflecting mirror is not limited to a parabolic cross section or an elliptic curve cross section, but a cross section may be changed. Similar effects can be obtained by using other curves that are similar to such a quadratic curve.

Further, the optical reflecting element 5 shown in each embodiment
Although 1, 60, 68, and 76 have a one-piece structure, they may be separated into a two-body structure as shown by a chain line A in FIG.

[0061]

As described above, according to the optical reflecting element of the present invention, since all the incident light is incident from the incident surface at the same incident angle, the reflective surface reflects all the light in a predetermined direction. . As a result, it becomes an extremely effective optical means for condensing and reflecting the incident light, and it becomes an optical reflecting element convenient for mounting. Further, since it can be integrally formed with the light receiving element, it is effective as an optical reflection element for photoelectric conversion, and further, by forming the reflection surface as a mirror surface, the shape of the reflection surface can be arbitrarily formed.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of a photoelectric conversion device showing a first embodiment of the present invention.

FIG. 2 is a principle configuration diagram of a photoelectric conversion device showing a second embodiment of the present invention.

FIG. 3 is a principle configuration diagram of a photoelectric conversion device showing a modification of the first embodiment.

FIG. 4 is a principle configuration diagram of a photoelectric conversion device showing a third embodiment of the present invention.

FIG. 5 is a principle block diagram of a photoelectric conversion device showing a fourth embodiment of the present invention.

FIG. 6 is a principle configuration diagram of a conventional photoelectric conversion device.

FIG. 7 is an optical system diagram for explaining properties of a convex mirror used in a conventional photoelectric conversion device.

FIG. 8 is a diagram illustrating another principle of the conventional photoelectric conversion device.

9A is a cross-sectional view of an optical reflecting element provided in a conventional photoelectric conversion device, and FIG. 9B is a partially enlarged cross-sectional view of the optical reflecting element.

[Explanation of symbols]

 50, 59, 67, 75 Concave mirror 51, 60, 68, 76 Optical reflection element 52, 61, 69, 77 Circular outer surface portion 53, 62, 70, 78 Curved surface portion 55, 63, 72, 79 Light receiving element

Claims (3)

[Claims] 1. A reflection surface obtained by axially rotating a curve having a focal point, and an incident surface obtained by axially rotating an arc drawn around the focal point on the optical path of light directed to the focal point. An optical reflection element comprising a transparent material. 2. The optical reflection element according to claim 1, wherein the light receiving element located in the reflection optical path of the reflection surface is embedded and integrally fixed. 3. The optical reflection element according to claim 1, wherein the reflection surface is formed as a mirror surface.