JP2874886B2 - Beam splitter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beam splitter for splitting one incident beam into a plurality of beams.

2. Description of the Related Art The present applicant filed Japanese Utility Model Application No. 62-21732 (Japanese Utility Model Application No.
Has developed a new locking system. This lock system converts light emitted from the lock device into a predetermined code signal by an optical device provided on a key, and unlocks the light when the converted light is received by the lock device. Device.

This optical lock control device will be described with reference to FIGS.

As shown in FIGS. 6 and 7, the light emitting device 11 includes a board 21 disposed adjacent to a key insertion portion 20 of a steering lock device for locking a steering shaft of an automobile;
It has a pair of infrared light emitting diodes 22 arranged opposite to the key insertion part 20. Further, as shown in FIG. 8, the light receiving sensors 14 to
17 are arranged in a line. As shown in FIG.
Are a metal key blade 23, a light-guiding resin head 24 formed at one end of the key blade 23, and a head 24.
And a light guide member 13 provided therein. The key blade 23 of the key 12 is inserted into the key cylinder 25 of the steering lock device at the time of unlocking, as shown in FIGS. 6 and 7.

The light guide member 13 is formed of a light transmissive resin such as silicone resin or acrylic resin as shown in FIG.
A light-receiving part 30 formed at one end of the light-receiving part 30, a light-guiding part 31 branched into four parts from the light-receiving part 30, and a light-receiving part 30 formed at the other end of each light-guiding part 31
And two light emitting sections 32. The light receiving part 30 is exposed from the head part 24 on one side of the key blade 23, and the infrared light emitting diode
Receives 22 lights. A reversible key that can be unlocked even when inserted into the key cylinder 25 in a state in which the current car key is rotated by 180 degrees is frequently used. For this reason, key 12
7 is rotated 180 degrees from the state shown in FIG. 7 and inserted into the key cylinder 25 so that the infrared light emitted from the light receiving section 30 can be received. Is provided.

The light guide part 31 of the light guide member 13 passes through the inside of the head part 24 and emits light.
Each end face of 32 is exposed from the linear edge 26 of the head 24. Key 12 in the key cylinder of the steering lock device
Is inserted, when rotated from the lock position to the start position, the infrared light emitted from the light emitting diode 22 at the start position reaches the light emitting portion 32 from the light receiving portion 30 of the light guiding member 13 through the light guiding portion 31 . The infrared light emitted from the light emitting section 32 to the outside of the light guide member 13 is received by the light receiving sensors 14 to 17. In the illustrated example, the light guide part 31 of the light guide member 13 is branched into four parts.
Although two light emitting units 32 are provided, some of the four light emitting units 32 are selectively cut off, and a key code is set.
That is, an optical key code is set based on the presence or absence of infrared light on the light receiving sensors 14 to 17.

The conventional light guide member 13 is formed in an arc shape in order to prevent light from leaking through the light guide unit 30. By forming the light guide 30 in an arc shape, the traveling direction of light passing through the light guide 30 is always equal to or smaller than the critical angle with respect to the outer surface of the light guide 30. For this reason,
The amount of light leakage from the light guide 30 can be significantly reduced. That is, the light guide unit 30 applies the theory of total reflection (Fresnel reflection) used in a conventional light guide fiber.

Problems Simulated by the Invention When a state in which a light beam passes through the light guide member 13 is simulated by using an electronic computer, a locus of the light beam shown in FIG. 11 is obtained. As is clear from FIG. 11, the light guide member
There is almost no light leakage from 13. Therefore, the light emitting unit 32
, A sufficient amount of light is supplied to the light receiving sensors 14 to 17.

However, light emitted from the light emitting unit 32 to the light receiving sensors 14 to 17 is diffused by the light emitting unit 32. Therefore, each light emitting unit 32
There is a case where the light emitted from is not accurately directed to any of the corresponding light receiving sensors 14 to 17 and is detected by another adjacent light receiving sensor. For this reason, there has been a defect that a correct key code cannot be given to the light receiving sensor, and a lock device such as a steering lock device cannot be unlocked even though a proper key is used.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a beam splitter which can solve the above-mentioned drawbacks and can irradiate a highly directional light beam.

Means for Solving the Problems A beam splitter according to the present invention irradiates a plurality of light receiving sensors (14 to 17) arranged apart from each other from a light source (22) provided in an optical lock device with a light beam, This is a light guide member used for an optical lock device that gives an optical key code by detecting the presence or absence of a light beam. The beam splitter includes a plurality of light emitting units (52) for guiding a light beam to light receiving sensors (14 to 17) by a plurality of reflecting surfaces (53).
And a light guide portion (50) integrally formed of a light guide material having the following. The plurality of reflecting surfaces (53) are paraboloids whose axes are lines (Y) perpendicular to the key insertion direction, and the light source (22) of the light beam is disposed at the focal point of the paraboloid.

Further, the beam splitter according to the embodiment of the present invention includes:
A light receiving unit (51) formed at an end of the light guide unit (50) and a plurality of second reflecting surfaces (55) for reflecting a light beam from the reflecting surface (53) toward the light emitting unit (52). ). An inclined third reflecting surface (56) is formed on the light receiving unit (51), and the light beam emitted from the light source (22) is incident on the light receiving unit (51), and then the third reflecting surface (56) is formed. And goes straight toward the plurality of reflection surfaces (53). The second reflecting surface (55) is a plane that reflects the light beam reflected by the plurality of reflecting surfaces (53) in a direction substantially perpendicular to the light beam.

A beam splitter according to an embodiment of the present invention includes a light guide unit (50) integrally formed of a light guide material, a light receiving unit (51) formed at one end of the light guide unit (50), and a light guide unit (50). A plurality of light emitting portions (52) formed at the other end of the light guide portion (50), and a light beam that enters the light guide portion (50) from the light receiving portion (51) and travels straight through the light guide portion (50) is substantially changed. First reflective surface that reflects at right angles (53)
A branch part (54) for dividing the light beam reflected and traveling straight on the first reflection surface (53) into a plurality of light beams, and a plurality of light beams divided and traveling straight by the branch part (54), respectively. A plurality of second reflecting surfaces (55) that reflect toward the corresponding light emitting portion (52).

The first reflection surface (53) is a paraboloid whose focal point is a light source (22) arranged at a predetermined distance from the light receiving unit (51). The entire surface of the beam splitter is mirror-finished. The first reflecting surface (53) is a plane inclined at an angle slightly smaller than the critical angle at the first reflecting surface (53) with respect to the path of the light beam that enters from the light receiving portion (51) and goes straight. .

The light beam from the light source (22) is reflected by a plurality of reflecting surfaces (53) formed by paraboloids and then deflected into parallel light beams. 14 to 17), and the light receiving sensor (14 to 1)
7) Can operate accurately.

Further, the beam splitter can be integrally formed of a light guide material. Further, since the first reflecting surface (53) is formed as a paraboloid, the light beam incident on the light guide portion (50) from the light receiving portion (51) is substantially perpendicular to the first reflecting surface (53). Incident. At this time, part of the light incident on the first reflecting surface (53) at a large angle exceeding the critical angle on the first reflecting surface (53) is emitted outward from the first reflecting surface (53). . The light beam reflected from the first reflecting surface (53) and traveling straight is split into a plurality of light beams at the branching portion (54), and then reflected by the corresponding second reflecting surface (55). Second reflective surface (5
Even in 5), part of the light incident at an incident angle exceeding the critical angle may be emitted to the light guide (50). Second reflective surface (5
The light beam reflected and traveling straight in 5) is emitted from the light emitting section (52). As described above, the light traveling out of the predetermined angle range and traveling in the light guide (50) is emitted to the outside of the light guide (50) on the reflection surfaces (53, 55), so that the light emission (52) ) Gives directivity to the light beam emitted to the outside of the light guide (50). The first reflecting surface (53) is a light receiving section (51)
The light beam is directed to the first reflecting surface (53) to form a paraboloid whose focal point is a light source (22) arranged at a certain distance from the light source (22).
The light beam is deflected to a parallel light beam, and a directional light beam can be emitted from the light emitting section (52) with a sufficient amount of light.

Embodiment An embodiment of a beam splitter according to the present invention will be described below with reference to FIGS.

The beam splitter according to the present invention includes a light guide unit 50 integrally formed of a light guide material and extending in the key insertion direction, a light receiving unit 51 formed at one end of the light guide unit 50, and the other end of the light guide unit 50. A plurality of light emitting units 52 formed in the
And a first reflecting surface 53 that reflects the light beam that travels straight through the light guide unit 50 in a substantially right angle direction, and the light beam that reflects on the first reflecting surface 53 and travels straight into a plurality of light beams. It has a branching section 54 for splitting, and a plurality of second reflecting surfaces 55 for reflecting a plurality of light beams, which are split by the branching section 54 and travel straight, toward the corresponding light emitting sections 52, respectively.

The light guide section 50 is formed substantially T-shaped and symmetrical in the illustrated example. As the light guide material forming the light guide unit 50, for example, a synthetic resin such as an acrylic resin, a polycarbonate resin, an acrylic glycol carbonate resin (CR39), and polymethyl methacrylate (PMMA), or glass can be used. The entire surface of the beam splitter is mirror-finished, and the surface forms a smooth surface without irregularities. This can be easily obtained by mirror-finishing the inner surface of the mold forming the beam splitter.

A third reflecting surface 56 that is inclined is formed on the light receiving unit 51.
This is because the light beam emitted from the infrared light emitting diode 22 as the light source and incident on the light guide unit 50 from the light receiving unit 51 is reflected by the third reflecting surface 56 toward the first reflecting surface 53. The infrared light reflected by the third reflecting surface 56 goes straight toward the first reflecting surface 53. In the illustrated embodiment, as shown in FIG. 5, the first reflecting surface 53 is a paraboloid whose focal point is the light source of the infrared light emitting diode 22 arranged at a fixed distance from the light receiving section 51. The first reflection surface 53 is a paraboloid whose axis is a line Y perpendicular to the key insertion direction. In this case, the infrared light emitting diode 22 as a light source is
However, since the light beam is reflected by the first reflecting surface 53, it can be geometrically arranged at the focal point of the paraboloid. Although the first reflection surface 53 is formed in a substantially V shape, the light guide portion 50 may not be T-shaped and the first reflection surface 53 may be formed on only one side. By the way, when the light guide 50 is formed of polycarbonate or polymethyl methacrylate, the critical angle with air is 39 degrees, 42 degrees.
Degrees. Therefore, it is desirable that the angle α between the light beam and the first reflecting surface 53 is slightly smaller than the critical angle at the first reflecting surface 53. It is clear that the critical angle α is determined by the refractive index of the material of the light guide 50 and the refractive index of air. Therefore, the light that does not travel straight in the light guide unit 50 and that has a risk of impairing the directivity of the light reflected from the peripheral wall of the light guide unit 50 or the light emitted from the light emitting unit 52 is emitted from the first reflection surface 53. Can be released to the outside.

The branching unit 54 converts the light beam reflected by the first reflecting surface 53 into two light beams.
It is formed in a bifurcated shape divided in the direction. A step portion 57 is formed outward from the branch portion 54. The step 57 is for compensating for the thickness of the key blade 23 shown in FIG. 9 and for arranging the light emitting section 52 substantially linearly along the light receiving sensors 14 to 17.

The second reflecting surface 55 is a plane that reflects the light beam reflected by the first reflecting surface 53 in a substantially right angle direction. Of course, the second reflection surface 55 may be formed as a curved surface such as a paraboloid.

In the above configuration, the light beam emitted from the infrared light emitting diode 22 and incident on the light guide unit 50 from the light receiving unit 51 is reflected by the first reflection surface 53 in a substantially right angle direction. At this time, as shown in FIG. 4, a part of the light incident on the first reflecting surface 53 at a large angle exceeding the critical angle on the first reflecting surface 53 is emitted outward from the first reflecting surface 53. Is done. First reflective surface
The light beam reflected from the light beam 53 and traveling straight is split into a plurality of light beams by the branch portion 54, and then reflected by the corresponding second reflection surface 55. In the second reflection surface 55, part of the light incident at an incident angle exceeding the critical angle may be emitted to the outside of the light guide unit 50. In addition, the light reflected by the light emitting surface 52 is
May be released from The light beam reflected by the second reflection surface 55 and traveling straight is emitted from the light emitting section 52. In this manner, light that goes straight through the light guide unit 50 deviating from the predetermined angle range is emitted to the outside of the light guide unit 50 on the reflection surface,
Directivity is given to the light beam emitted from the light emitting unit 52 to the outside of the light guide unit 50. For this reason, the light receiving sensor to which the light emitted from the light emitting unit 52 corresponding to the light receiving sensors 14 to 17 does not correspond
It is possible to prevent malfunctions detected at 14 to 17. According to the present invention, substantially all of the light received by the light receiving unit 51 cannot be transmitted to the light emitting unit 52, but the light emitted from the light emitting unit 52 has practically sufficient light quantity and directivity.

The above embodiment of the present invention can be variously modified.
For example, the light guide 50 can be changed to other various shapes. Further, the number of the light emitting sections 52 may be three or less or five or more. Further, light such as visible light other than infrared light can be used. In the above-described embodiment of the present invention, an example is described in which the lock device uses infrared light. However, the present invention can be applied to splitting a light beam in a device other than the lock device.

Effect of the Invention As described above, according to the present invention, since the beam splitter can be formed integrally with the light guide material,
The manufacture of the beam splitter is easy. In addition, since the directivity of light emitted from the light emitting unit can be improved,
An optical device without malfunction can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view of a beam splitter according to the present invention, FIG. 2 is a bottom view, FIG. 3 is a side view, FIG. 4 is a simulation diagram showing a state in which a light beam passes through the beam splitter according to the present invention. FIG. 5 is a graph illustrating a first reflecting surface, FIG. 6 is a partial cross-sectional view showing a state where a key provided with a conventional light guide member is inserted into a steering lock device,
FIG. 7 is a partial sectional view of FIG. 6 shifted by 90 °, FIG. 8 is a sectional view taken along line AA of FIG. 6,
FIG. 9 is a perspective view of the key, FIG. 10 is a front view of the light guide member, and FIG.
FIG. 11 is a simulation diagram showing a state in which a light beam passes through the conventional light guide member shown in FIG. 50 light guide portion, 51 light receiving portion, 52 light emitting portion, 53 first reflection surface, 54 branch portion, 55 second reflection surface, 56
... the third reflective surface,

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E05B 19 / 00,49 / 00 G02B 6 / 28,27 / 10

Claims (9)

(57) [Claims] A plurality of light receiving sensors (14 to 17) spaced apart from a light source (22) provided in an optical lock device.
A light guide member for use in an optical lock device that applies an optical key code by irradiating a light beam to the light source and detecting the presence or absence of the light beam. The light beam is received by a plurality of reflection surfaces (53). The light guide section (5) integrally formed of a light guide material having a plurality of light emission sections (52) leading to the sensors (14 to 17).
0), the plurality of reflecting surfaces (53) are paraboloids whose axis is a line (Y) perpendicular to the key insertion direction, and the light source (22) of the light beam is focused on the paraboloid. A beam splitter, wherein the beam splitter is arranged in a beam splitter. 2. A light receiving section (51) formed at an end of a light guide section (50) and a light emitting section (52) for emitting a light beam from a reflection surface (53).
The beam splitter according to claim 1, comprising a plurality of second reflecting surfaces (55) that reflect toward. 3. An inclined third reflecting surface (56) is formed on the light receiving section (51), and a light beam emitted from the light source (22) is incident on the light receiving section (51), and then the third reflecting surface is formed. The beam splitter according to claim 2, wherein the beam is reflected by the reflection surface (56) and travels straight toward the plurality of reflection surfaces (53). 4. The second reflecting surface (55) includes a plurality of reflecting surfaces (53).
3. The beam splitter according to claim 2, wherein the beam splitter is a plane that reflects the light beam reflected in the direction substantially perpendicularly. 5. A light guide unit (50) integrally formed of a light guide material.
A light receiving unit (51) formed at one end of the light guide unit (50);
A plurality of light emitting units (52) formed at the other end of the light guide unit (50)
A first reflecting surface (53) for reflecting a light beam incident from the light receiving portion (51) into the light guide portion (50) and traveling straight in the light guide portion (50) in a substantially right angle direction; A branching portion (54) for dividing a light beam that is reflected by the reflecting surface (53) and travels straight into a plurality of light beams, and emits a plurality of light beams that are divided by the branching portion (54) and travel straight ahead, respectively. In a beam splitter having a plurality of second reflecting surfaces (55) reflecting toward a portion (52), a first reflecting surface (53) is provided at a light source ( 22) A beam splitter characterized by having a parabolic surface focused on. 6. A light-receiving section (51) is provided with an inclined third reflection surface (56), and a light beam emitted from a light source (22) is incident on the light-receiving section (51) and then becomes a third light-reflecting surface. The beam splitter according to claim 5, wherein the beam is reflected by the reflecting surface (56) and travels straight toward the first reflecting surface (53). 7. The beam splitter according to claim 5, wherein the entire surface is mirror-finished. 8. The second reflecting surface (55) is a first reflecting surface (53).
The beam splitter according to claim 5, wherein the beam splitter is a plane that reflects the light beam reflected in the direction substantially perpendicularly. 9. The first reflecting surface (53) has an angle slightly smaller than the critical angle at the first reflecting surface (53) with respect to the path of the light beam that enters from the light receiving portion (51) and goes straight. The beam splitter according to claim 5, wherein the beam splitter is an inclined plane.