JP2006349604A - Optical encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized optical encoder which is easily installed while keeping the positional relation with other members unchanged. <P>SOLUTION: The optical encoder comprises a bare chip LED 141; an optically transparent substrate 111 having a first grating 110 provided on a surface for emitting optical beam of the bare chip LED 141; a second grating 120 displaced so as to cross the optical beam emitted from the bare chip LED 141 through the first grating 110 and having an optical pattern of a predetermined cycle p2; and a light detector 150 detecting movement of a diffraction pattern formed by emitting the optical beam to the optical pattern. The optically transparent substrate 11 is directly arranged on the bare chip LED 141, the light detector 150 includes a light receiving element array 151 arranged at a predetermined pitch p3, and the first grating 110 has a slit longer than the length of the light emitting area of the bare chip LED 141 in a direction substantially orthogonal to the pitch direction of the light receiving element array 151. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reflective optical encoder that detects the position and the like of an object to be detected.

  FIG. 14 shows a configuration of a conventional light emitting device for an encoder. In FIG. 14B, the cover 15 is formed by punching a thin metal plate such as SUS. The cover 15 includes a slit 15a formed in a horizontally narrow width, ear pieces 15b and 15c formed on both sides of the upper portion, a cover body 15d, and leg portions 15e.

  A folding line 15x is formed between the cover body 15d and the ear pieces 15b, 15c on both sides. Further, a folding line 15y is formed between the cover main body 15d and the leg portion 15e.

  The cover 15 shown in FIG. 14B is bent along folding lines 15x and 15y and attached to the light emitting surface of the LED element 11x. FIG. 14A is a schematic side view showing a state in which the cover 15 is attached to the light emitting surface of the LED. In FIG. 14A, the LED element 11x is provided with an electrode 11a and an electrode 11b. The electrode 11b is electrically connected to the lead terminal 12 by die bonding. Although not shown, a metal wire is connected to the electrode 11a. The metal wire is electrically connected to the other lead terminal by wire bonding.

  The cover 15 is aligned so that the center position of the light emitting surface of the LED element 11x is the position of the slit 15a, and is bent in the horizontal direction shown in the figure by folding lines 15x and 15y. Further, the ear pieces 15b and 15c and the leg portion 15e are bent in the vertical direction at an appropriate position. Thereby, the cover 15 is attached to the front surface of the light emitting surface of the LED element 11x.

  In this way, after the cover 15 is attached to the front surface of the light emitting surface of the LED element 11x, the LED element 11x and the metal wire are sealed with a mold part made of a translucent resin material, and the LED 11 is then sealed. Form. For this reason, the cover 15 is firmly fixed by the mold part and can prevent the occurrence of displacement. Further, it is not affected by the positional deviation of the LED element 11x during die bonding.

  The LED 11 shown in FIG. 14A has a cover in which the position of the horizontally long and narrow slit 15a is aligned with the center position of the light emitting surface of the LED element 11x. For this reason, the output light emitted from the LED element 11x passes through only the slit 15a, and the light beam La travels toward the light receiving unit.

  Further, the cover 15 provided with the slits 15a can be easily formed by punching. In addition, instead of forming the cover 15 by punching, bending and attaching it to the light emitting surface of the LED element 11x, a cover provided with a slit 15a so that the side view has the shape shown in FIG. 15 can also be formed by molding a synthetic resin material.

JP 2001-135862 A

  In order to manufacture a so-called reflective optical encoder in a compact and inexpensive manner, it is necessary to mount a light source, in particular, a bare chip light source and a slit in combination. At this time, it is difficult to mount small miniaturized components in a predetermined positional relationship. For example, in a reflective optical encoder, it is necessary to accurately align the direction of the grating on the light source side and the direction of the photodetector. Such alignment is extremely difficult in a miniaturized optical encoder.

  The present invention has been made in view of the above, and an object of the present invention is to provide an optical encoder that is small in size and easy to mount while maintaining a constant positional relationship with other members.

  In order to solve the above-described problems and achieve the object, according to the present invention, a light source that emits a light beam and a light transmissive member that forms a first grating provided on the surface of the light source that emits the light beam. And a second grating on which an optical pattern having a predetermined period is formed by being displaced so as to cross the light beam transmitted through the first grating from the light source, and the optical pattern having the predetermined period is irradiated with the optical pattern. And an optical encoder that detects the movement of the diffraction pattern generated by the light source, wherein the light source is a bare chip light source, the light transmissive member is directly disposed on the bare chip light source, and the photodetector is The first grating has slits longer than the length of the light emitting region of the light source in a direction substantially perpendicular to the pitch direction of the light receiving element array. It can provide an optical encoder that.

  According to a preferred aspect of the present invention, it is desirable that the region where the pattern of the first grating is provided is overhanging than the light emitting region of the bare chip light source.

  According to a preferred aspect of the present invention, it is desirable that the light transmissive member is a planar substrate, and the center of gravity of the light transmissive member exists at least in the surface of the bare chip light source.

  Moreover, according to the preferable aspect of this invention, it is desirable for the light transmissive member to overhang in the pitch direction of a 1st grating | lattice on the surface of a bare chip light source.

  Moreover, according to the preferable aspect of this invention, it is desirable for the light transmissive member to overhang in the direction substantially orthogonal to the pitch direction of a light receiving element array on the surface of a bare chip light source.

  Further, according to a preferred aspect of the present invention, at least a part of the light transmissive member facing the surface electrode of the bare chip light source is formed with a notch-shaped or hole-shaped opening, and through the opening to the surface electrode of the bare chip light source. It is desirable that a conductive wire be bonded.

  According to a preferred aspect of the present invention, the light transmissive member is formed of an insulating member, and conductive electrode patterns are formed on the upper and lower surfaces of the light transmissive member. It is desirable that the pad is electrically connected through a through hole, and a conductive wire is bonded from the electrode pattern on the upper surface.

  Further, according to a preferred aspect of the present invention, it is desirable that the conductive substrate is directly disposed on the bare chip light source, and the conductive wire is bonded on a plane facing the second grating.

  According to a preferred aspect of the present invention, the photodetector and the bare chip light source are in contact with each other in the space between the photodetector and the bare chip, and are larger in the pitch direction of the first grating than the width of the bare chip light source. It is desirable that a mounting auxiliary member having a width is mounted, and further, the light transmissive member is mounted on the mounting auxiliary substrate in contact with the photodetector.

  Further, according to a preferred aspect of the present invention, it is desirable that the mounting auxiliary member surrounds the bare chip light source except for a portion in a direction opposite to a portion in contact with the photodetector.

  According to a preferred aspect of the present invention, it is desirable that the mounting assisting member has a light shielding film or a high reflection film formed on a side surface facing the bare chip light source.

  The optical encoder according to the present invention is a so-called reflective optical encoder, wherein the light source is a bare chip light source, and the light transmissive member is directly disposed on the bare chip light source. Thereby, a small optical encoder can be provided. The photodetector has a light receiving element array arranged at a predetermined pitch, and the first grating has a slit longer than the length of the light emitting region of the light source in a direction substantially perpendicular to the pitch direction of the light receiving element array. is doing. Thereby, it is easy to adjust the positional relationship between the first grating and the light receiving element array to a fixed relationship. Thus, according to the present invention, it is possible to provide an optical encoder that is small in size and easy to mount while keeping the positional relationship with other members constant.

  Embodiments of an optical encoder according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  An optical encoder 100 according to Embodiment 1 of the present invention will be described with reference to FIGS. The bare chip LED 141 is a light emitting element manufactured by an optical semiconductor process. The bare chip LED 141 in the present embodiment has a configuration in which the emission diameter is controlled.

  The first grating 110 is an optical pattern having a constant period p1 formed on the light transmissive substrate 111. The light transmissive substrate 111 is a planar light transmissive member. The optical pattern may be formed directly on the light-transmitting substrate 111 or may be affixed with a sheet-like pattern.

  The second grid 120 is formed on the scale 121. The second grating 120 has a configuration in which a region having a high reflectance and a region having a low reflectance are formed in a constant cycle p2, or a configuration in which a concave portion and a convex portion are formed in a constant cycle p2. As a result, a light / dark pattern can be formed on the photodetector 150.

  The photodetector 150 includes a light receiving element array 151 for detecting signals having different phases. The photodetector 150 may have a configuration in which a plurality of pairs of the light receiving element arrays 151 are arranged to be shifted, or a configuration of a photodetector through a third grating having different phases.

  Next, the operation of the optical encoder 100 will be described. The light beam emitted from the bare chip LED 141 is applied to the light transmissive substrate 111 having the pattern of the first grating 110 disposed on the surface facing the emission surface of the bare chip LED 141. The light beam that has passed through the first grating 110 is applied to the second grating 120 on the scale 121 that operates in parallel with the pitch direction (y direction) of the first grating 110. Here, the interval z1 between the second grating 120 and the first grating 110 and the interval z2 between the second grating 120 and the photodetector 150 are configured to be maintained at a predetermined distance. As a result, the light beam reflected by the second grating 120 transfers a light / dark pattern of the first grating 110, a so-called self-image, onto the photodetector 150. The light receiving element array 151 detects the movement of the light / dark pattern.

  FIG. 2 shows an enlarged view of the light receiving element array 151 formed on the photodetector 150. In the light receiving element array 151, for example, a plurality of four rectangular photodiodes PD1, PD2, PD3, and PD4 are combined.

  The photodiodes PD1, PD2, PD3, and PD4 are arranged in a comb shape with a shift of 1/4 × p3. Then, electric signals from the respective photodiodes PD1, PD2, PD3, and PD4 are output from the four electrode pads A1, B1, A2, and B2.

  When the scale 121 is relatively moved in the y direction, pseudo sine wave signals having phases different from each other by a quarter period are obtained from the four electrode pads A1, B1, A2, and B2. Thereby, it is possible to detect the direction of displacement (discrimination of the moving direction). Furthermore, by performing interpolation processing of the output signal (displacement amount interpolation processing), it is possible to detect the displacement amount with a resolution much finer than the pitch of the second grating 120 formed on the scale 121. is there.

  At this time, the pitch direction of the first grating 110 (y direction), the pitch direction of the second grating 120 (y direction), and the pitch direction of the light receiving element array 151 on the photodetector 150 (y direction) are kept parallel. It is desirable. Thereby, the output signal from the light receiving element array 151 becomes a pseudo sine wave, and a high-resolution displacement amount can be detected by signal processing.

  In addition, in order to effectively use the light beam from the bare chip LED 141, the position of the emission spot of the bare chip LED 141 and the first grating 110 is controlled, and the distance between the light receiving element array 151 on the photodetector 150 and the first grating 110 is controlled. There is a need to.

  In order to detect signals having different phases, a photodetector 150 having an arrayed light receiving element array 151 is mounted and disposed at a predetermined position on the substrate 160. Further, the bare chip LED 141 is mounted at a predetermined position by using the alignment mark or the like on the substrate 160 while being abutted against the photodetector 150. On the upper surface of the bare chip LED 141, the light-transmitting substrate 111 is disposed and mounted directly overhanging on the light receiving element array 151 side with respect to the bare chip LED 141.

  Thereby, it is possible to effectively utilize the large spread of the light beam emitted from the bare chip LED 141. Furthermore, the distance between the center of the bare chip LED 141 and the center of the photodetector 150 is greatly influenced by the output signal level, but by widening the area where the pattern of the first grating 110 is provided rather than the light emission area, The distance interval control becomes easy and the signal level can be secured.

  The light transmissive substrate 111 is formed of a light transmissive member for the light beam emitted from the bare chip LED 141. A periodic pattern of the first grating 110 is formed on the surface of the light transmissive substrate 111. In addition, a conductive wire 171 is wire-bonded on the surface electrode of the bare chip LED 141. For this reason, the light-transmitting substrate 111 is overhanged in the direction of the photodetector 150 to make a space.

  In the present embodiment, the first grating 110 formed on the light transmissive substrate 111 is formed on the surface facing the light emitting direction of the bare chip LED. For this reason, it is desirable to configure so that the thickness of the photodetector 150 and the thickness of the bare chip LED 141 are substantially the same. Thereby, the space | interval z1 and the space | interval z2 can be made to correspond substantially. As a result, the light / dark pattern on the second grating 120 is transferred to the surface of the photodetector 150 as a light / dark pattern having a size approximately twice as large.

  Further, in order to detect a high-resolution displacement, the pitch direction of the first grating 110 and the pitch direction of the second grating 120 and the pitch direction of the light receiving element array 151 need to be substantially parallel. For this reason, the light transmission opening position on the surface of the bare chip LED 141 and the opening pattern of the first grating 110 are aligned, and the light transmissive substrate 111 is directly attached to the bare chip LED 141. Thereby, the small and high-resolution optical encoder 100 can be realized.

  Here, the pattern of the first grating 110 on the light-transmitting substrate 111, the upper surface electrode 170 of the bare chip LED 141, the light emission opening (light emission) position, the opening width, and the like can all be manufactured by a pattern technique of a semiconductor process. For this reason, the tolerance variation of components can be made extremely small. As a result, the position arrangement can be controlled by direct pasting.

  In the present embodiment, the first grating 110 has a slit longer than the length of the light emitting region of the bare chip LED 141 in a direction substantially perpendicular to the pitch direction of the light receiving element array 151. Thereby, it is easy to adjust the positional relationship between the first grating 110 and the light receiving element array 151 to a fixed relationship. As described above, according to the present embodiment, it is possible to provide the optical encoder 100 that is small in size and easy to mount while keeping the positional relationship with other members constant.

  In the present embodiment, the light transmissive substrate 111 is a planar substrate, and the center of gravity exists at least in the surface of the bare chip LED 141. Since the light-transmitting substrate 111 is a minute light-transmitting member, the side surface is likely to be the front surface or the reverse side, and it is not easy to mount the correct surface on the bare chip light source. Therefore, by placing the center of gravity of the light transmissive substrate 111 on the bare chip LED 141 while confirming the pattern of the first grating 110, the light transmissive substrate 111 can be correctly fixed without rotating laterally.

  With reference to FIG. 4, the optical encoder 200 which concerns on Example 2 of this invention is demonstrated. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. The light transmitting substrate 111 is provided with a wire bonding hole 203. The conductive wire 171 is wire-bonded to the LED upper surface electrode 201 of the bare chip LED 141 through the wire bond hole 203. The light transmissive substrate 111 is directly attached on the bare chip LED 141 with the wire bonding hole 203 and the LED upper surface electrode 170 aligned. Thereby, the space which can insert the tip capillary of a wire bonding apparatus from an upper surface is securable. Here, the bare chip LED 141 is a constricted light emitting LED.

  In this embodiment, by providing the wire bonding hole 203 in the light transmissive substrate 111, it is not necessary to shift the positions of one end of the bare chip LED 141 and the light transmissive substrate 111 for wire bonding. For this reason, it is easy to stably adjust and mount the emission light emission position of the bare chip LED 141 and the arrangement position of the first grating 110 by determining the reference position of each component and directly bonding them.

  With reference to FIG. 5, an optical encoder 300 according to Embodiment 3 of the present invention will be described. The same parts as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and redundant description is omitted.

  The first grid 110 is formed at a position corresponding to the bare chip LED light emitting unit 301. Then, the light-transmitting substrate 111 provided with the wire bond notch portion 303 at a position corresponding to the LED upper surface electrode 302 is directly attached and mounted by aligning the bare chip LED 141 (positioning based on the shape by observation with the naked eye). To do.

  The LED upper surface electrodes 302 on the substrate of the bare chip LED 141 are arranged in the pitch direction of the first grating 110 so as to be parallel to the moving direction of the scale 121. This keeps the amount of reflected light from the conductive wire constant. Further, the LED upper surface electrode 302 can widen the pitch direction of the first grating 110. Correspondingly, since the space of the notch 303 in this direction is wide, there is an advantage that the conductive wire can be safely routed.

  In the case of wire bonding to the electrode pad, a space sufficiently larger than the diameter of the capillary is required when the tip capillary of the wire bonding apparatus contacts the electrode pad from above. If the space is narrow, there is a risk that the light-transmitting substrate 311 may be broken or cracked by the capillary, and stable wire bonding cannot be performed. As in this embodiment, by forming a notch-shaped opening in at least a portion of the light-transmitting substrate 311 facing the surface electrode of the bare chip LED 141, a conductive wire can be bonded to the surface electrode of the bare chip LED 141 through the opening. For this reason, stable wire bonding is possible.

  An optical encoder 400 according to Embodiment 4 of the present invention will be described with reference to FIGS. The same parts as those in the first to third embodiments are denoted by the same reference numerals, and redundant description is omitted. In this embodiment, the photodetector 150 is mounted at a predetermined position on the substrate 160. A mounting auxiliary member 403 wide in the pitch direction of the light receiving element array 151 is abutted against the photodetector 150 and mounted. Further, the bare chip LED 141 is mounted against the mounting auxiliary member 403. The light transmissive substrate 111 is disposed so as to avoid the LED upper surface electrode 402 of the bare chip LED 141. Then, the light-transmitting substrate 111 is directly attached on the mounting auxiliary member 403 and the bare chip LED 141 so that the end face of the light-transmitting substrate 111 is in contact with the photodetector 150.

  The LED upper surface electrode 402 and the electrode pad 170 of the bare chip LED 141 wire bond the conductive wire so that the tip capillary of the wire bonding apparatus does not hit the light transmissive substrate 111. By such a mounting procedure, the pitch direction of the first grating 110 formed on the light transmissive substrate 111 can be arranged in parallel with the pitch direction of the light receiving element array 151 formed on the photodetector 150.

  In addition, the pattern area of the first lattice 110 is overhanging the LED light emitting unit 401. Thereby, alignment of the light beam emitted from the bare chip LED 141 is facilitated. At the same time, a light beam can be effectively emitted from the first grating 110 and irradiated onto the surface of the second grating 120.

  The distance between the center of the light receiving element array 151 and the center of the first grating 110 is such that the photodetector 150 and the light transmissive substrate 111 are attached to each other, and the light transmissive substrate 111 further has an outer shape of the bare chip LED 141. Is overhanging. For this reason, the positions of the light receiving element array 151 and the first grating 110 can be easily adjusted without rotating.

  Further, in this embodiment, the light transmissive substrate 111 is overhanging on the surface of the bare chip LED 141 also in the pitch direction of the first grating 110. As a result, the pitch direction of the first grating 110 can be arranged parallel to the moving direction of the light / dark pattern on the photodetector 150 while suppressing the amount of inclination.

  In this embodiment, the light transmissive substrate 111 is overhanging on the surface of the bare chip LED 141 in the direction of the light receiving element array 151. As a result, the pitch direction of the first grating 110 can be arranged in parallel with the tilt amount being suppressed with respect to the pitch direction of the light receiving element array 151 on the photodetector 150.

  Thus, in the present embodiment, the mounting auxiliary member 403 that is in contact with each other between the photodetector 150 and the bare chip LED 141 and is sufficiently wide in the pitch direction of the first grating 110 with respect to the width of the bare chip LED 141 is mounted. The light-transmitting substrate 111 is mounted on the mounting auxiliary member 403 in contact with the photodetector 150. The bare chip LED 141 is mounted in contact with the mounting auxiliary member 403 at a portion in contact with the photodetector 150 in the pitch direction of the first grating 110. At the same time, since the light transmissive substrate 111 is mounted and disposed in contact with the photodetector 150, the distance between the center of the light receiving element array 151 on the photodetector 150 and the center of the first grating 110 can be controlled. it can. In addition, the amount of inclination of the pitch direction of the first grating 110 of the light transmissive substrate 111 with respect to the pitch direction of the light receiving element array on the photodetector 150 can be suppressed. As a result, according to the present embodiment, the optical encoder 400 that is small and easy to manufacture can be provided.

  An optical encoder 500 according to Embodiment 5 of the present invention will be described with reference to FIGS. The same parts as those in the first to fourth embodiments are denoted by the same reference numerals, and redundant description is omitted. In this embodiment, the mounting auxiliary member 503 is disposed so as to abut against the photodetector 150 and surround the bare chip LED 141. The mounting auxiliary member 503 is coated with a light shielding film 501 or a highly reflective film on the abutting surface and the side surface facing the bare chip LED 141.

  In this embodiment, as shown in FIG. 9, the width of the abutting surface is made sufficiently wider than the width of the bare chip LED 141. Further, the light-transmitting substrate 111 mounted on the bare chip LED 141 is similarly abutted against the photodetector 150, so that the mounting auxiliary member 503 on the lower surface is used as a mounting alignment. Thereby, the pitch direction of the 1st grating | lattice 110 and the pitch direction of the light receiving element array 151 can be arrange | positioned and mounted easily in parallel.

  Further, by making the light-transmitting substrate 111 sufficiently large with respect to the size of the bare chip LED, it can be easily horizontally mounted on the substrate 160. In addition, a part of the light-transmitting substrate 111 and the upper surface of the upper electrode of the bare chip LED 141 are opened at a notch. For this reason, normal wire bonding is possible.

  Further, the light shielding film 501 or the total reflection film is coated on the side surface of the light transmissive substrate 111, particularly the surface that abuts against and contacts the photodetector 150. When the pattern of the first grating 110 is formed on the surface facing the second grating 120 of the light transmissive substrate 111, the light shielding film 501 repeats between the lower surface of the light transmissive substrate 111 and the surface of the bare chip LED 141. Reflection can be reduced.

  Further, when the light beam emitted from the side surface of the bare chip LED 141 is directly incident on the light receiving element array 151 without being irradiated on the second grating 120, the DC level of the output signal is pushed up and the S / N ratio of the position information is lowered. End up. In this embodiment, the light beam emitted from the side surface of the bare chip LED 141 is configured to absorb the light shielding film 501 provided on the side surface of the mounting auxiliary member 503. As a result, the amount of light beam directly input to the photodetector 150 is reduced. As a result, it is possible to realize the optical encoder 500 that can suppress a decrease in the S / N ratio and detect a high-resolution displacement. Further, a configuration may be adopted in which a reflective film is provided instead of the shielding film and the light beam is returned to the bare chip LED 141.

  In the present embodiment, the mounting auxiliary member 503 surrounds the bare chip LED 141 except for the direction opposite to the portion in contact with the photodetector 150. The mounting auxiliary member 503 is disposed so as to surround the bare chip LED 141 except in the direction opposite to the abutting portion, so that the pitch direction of the first grating 110 on the light transmitting substrate 111 and the light receiving element array on the photodetector 150 are arranged. The pitch direction of 151 is substantially parallel, and the light transmissive substrate 111 can be easily mounted horizontally on the substrate.

  An optical encoder 600 according to Embodiment 6 of the present invention will be described with reference to FIGS. The same parts as those in the first to fifth embodiments are denoted by the same reference numerals, and redundant description is omitted. In the fifth embodiment, a notch portion is formed in a part of the light transmissive substrate 111 for wire bonding. On the other hand, the present embodiment is different in that a through hole 601 is formed. The light transmissive substrate 111 is made of an insulating member. The through hole 601 penetrates the electrode pad 602 provided on the surface facing the LED upper surface electrode 402 and the electrode pad portion on the other surface, and is electrically conductive. For this reason, a conductive wire can be wire-bonded by a normal technique with the electrode pad on the plane of the light-transmitting substrate 111 facing the scale 121.

  An optical encoder 700 according to Embodiment 7 of the present invention will be described with reference to FIGS. The same parts as those in the first to sixth embodiments are denoted by the same reference numerals, and redundant description is omitted. The slit plate 701 is a conductive material in which the surface of a conductive material such as copper, stainless steel, or aluminum is coated with gold or an alloy thin film. The first grating 110 can be easily formed by punching the slit plate 701 or chemical etching. The mounting auxiliary member 503 is inserted between the photodetector 150 and the bare chip LED 141. Thereby, the distance between the bare chip LED light emitting unit 401 and the center of the light receiving element array 151 on the photodetector 150 is controlled.

  The slit plate 701 is abutted against the photodetector 150, and the bare chip LED light emitting unit 401 is aligned and mounted from the opening 110 a of the first grating 110. At this time, the pattern region of the first lattice 110 is overhanging sufficiently wider than the region of the bare chip LED light emitting unit 401. For this reason, the alignment is easy.

  The slit plate 701 is made of a conductive material as described above. For this reason, it is possible to easily perform wire bonding on the upper surface of the slit plate 701 without the capillary being obstructed by the slit plate 701. Furthermore, an electrode pad made of gold is disposed on the surface of the slit plate 701 facing the light emitting surface of the bare chip LED 141. For this reason, the electrode pad has a function of a reflection mirror as a gold electrode. Thereby, there is an effect of increasing the output of the light beam of the bare chip LED 141 by the recycling effect of returning the light to the bare chip LED light emitting unit 401.

  The present invention can take various modifications without departing from the spirit of the present invention.

  As described above, the optical encoder according to the present invention is useful for an optical encoder that is small in size and easy to mount while maintaining a constant positional relationship with other members.

It is a figure which shows the isometric view structure of the optical encoder which concerns on Example 1 of this invention. 2 is a diagram illustrating a configuration of a light receiving element array in Embodiment 1. FIG. 1 is a diagram illustrating a cross-sectional configuration of an optical encoder according to Embodiment 1. FIG. 7 is a diagram illustrating a perspective configuration of an optical encoder according to Embodiment 2. FIG. FIG. 9 is a diagram illustrating a perspective configuration of an optical encoder according to a third embodiment. FIG. 10 is a diagram illustrating a cross-sectional configuration of an optical encoder according to a fourth embodiment. FIG. 9 is a diagram illustrating a planar configuration of an optical encoder according to a fourth embodiment. FIG. 10 is a diagram illustrating a cross-sectional configuration of an optical encoder according to a fifth embodiment. FIG. 10 is a diagram illustrating a planar configuration of an optical encoder according to a fifth embodiment. FIG. 10 is a diagram illustrating a cross-sectional configuration of an optical encoder according to a sixth embodiment. FIG. 10 is a diagram illustrating a planar configuration of an optical encoder according to a sixth embodiment. FIG. 10 is a diagram illustrating a cross-sectional configuration of an optical encoder according to a seventh embodiment. FIG. 10 is a diagram illustrating a planar configuration of an optical encoder according to a seventh embodiment. It is a figure which shows the structure of the light-emitting device for encoders which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Optical encoder 110 1st grating | lattice 110a 1st grating | lattice opening part 111 Light transmission board | substrate 120 2nd grating | lattice 121 Scale 141 Bare chip LED
DESCRIPTION OF SYMBOLS 150 Photodetector 151 Light receiving element array 170 Electrode pad 171 Conductive wire 200 Optical encoder 201 LED upper surface electrode 202 Bare chip LED light emission part 203 Wire bonding hole part 300 Optical encoder 301 Bare chip LED light emission part 302 LED upper surface electrode 303 Notch for wire bonding Part 311 light transmissive substrate 400 optical encoder 401 LED light emitting part 402 LED upper surface electrode 403 mounting auxiliary member 500 optical encoder 501 shielding film 502 shielding film 503 mounting auxiliary member 600 optical encoder 601 through hole 602 electrode pad 700 optical encoder PD1, PD2, PD3, PD4 Photodiode 11 LED
11x LED element 11a, 11b Electrode 12 Substrate 15 Cover 15a Slit 15b, 15c Ear piece 15d Cover body 15e Leg 15x, 15y Folding curve

Claims (11)

A light source that emits a light beam; a light transmissive member that forms a first grating provided on a surface that emits the light beam of the light source; and a light beam that is emitted from the light source through the first grating. A second grating that is displaced across and has an optical pattern with a predetermined period formed thereon, and a photodetector that detects the movement of a diffraction pattern generated by irradiating the optical pattern with the optical beam with the predetermined period. An optical encoder comprising:
The light source is a bare chip light source;
The light transmissive member is directly disposed on the bare chip light source,
The photodetector has a light receiving element array arranged at a predetermined pitch,
The optical encoder according to claim 1, wherein the first grating has a slit longer than a length of a light emitting region of the light source in a direction substantially orthogonal to the pitch direction of the light receiving element array.   2. The optical encoder according to claim 1, wherein a region where the pattern of the first grating is provided is overhanging a light emitting region of the bare chip light source.   2. The optical encoder according to claim 1, wherein the light transmissive member is a planar substrate, and a center of gravity of the light transmissive member exists at least in a surface of the bare chip light source.   The optical encoder according to claim 1, wherein the light transmissive member overhangs in a pitch direction of the first grating on the surface of the bare chip light source.   2. The optical encoder according to claim 1, wherein the light transmissive member is overhanging on a surface of the bare chip light source in a direction substantially orthogonal to a pitch direction of the light receiving element array. At least a portion of the light transmissive member that faces the surface electrode of the bare chip light source is formed with a notch-shaped or hole-shaped opening,
The optical encoder according to any one of claims 2 to 5, wherein a conductive wire is bonded to a surface electrode of the bare chip light source through the opening. The light transmissive member is formed of an insulating member,
Conductive electrode patterns are formed on the upper and lower surfaces of the light transmissive member,
2. The optical encoder according to claim 1, wherein the electrode pads on the upper surface and the lower surface are electrically connected by through holes, and conductive wires are bonded from the electrode pattern on the upper surface. A conductive substrate is directly disposed on the bare chip light source,
2. The optical encoder according to claim 1, wherein a conductive wire is bonded on a plane facing the second grating. Mounting aid having a width larger than the width of the bare chip light source in the pitch direction of the first grating in contact with each other between the photodetector and the bare chip light source in the space between the photodetector and the bare chip The parts are mounted,
The optical encoder according to claim 6, wherein the light transmissive member is mounted on the auxiliary mounting substrate in contact with the photodetector.   The optical encoder according to claim 9, wherein the mounting auxiliary member surrounds the bare chip light source except for a portion in a direction opposite to a portion in contact with the photodetector.   The optical encoder according to claim 10, wherein the mounting auxiliary member has a light shielding film or a high reflection film formed on a side surface facing the bare chip light source.

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