TWI651938B - Optical scanning double-layer light-guiding encoder - Google Patents

Abstract

The invention provides an optical scanning double-layer light guiding encoder, which comprises a double-layer light guiding type grating wheel, a light emitting module, and a light sensing module. The light sensing module comprises a plurality of sensing elements adjacent to the double-layer light-guiding grating wheel, and the plurality of bare sensing regions of the plurality of sensing elements are laterally offset from each other and extend laterally along a plurality of mutually parallel different horizontal lines. . The optical scanning double-layer light guiding encoder provided by the invention can match the light beam projected on the light sensing module with the plurality of bare sensing regions of the plurality of sensing elements, thereby not increasing the double-layer light guiding Improve the resolution of the encoder under the condition of the size of the grid wheel and the number of blades.

Description

 Optical scanning double-layer light guiding encoder  

The invention relates to an encoder, in particular to an optical scanning double-layer light guiding encoder.

Today's computer monitors use the mouse to move the location of the data to be processed to a specific data location on the monitor. The main structure of a typical mouse consists of two sets of X-axis and Y-axis encoders that output sequence logic signals (eg 11, 10, 00, 01), which are moved by moving the bottom of the mouse against a table or other plane to a specific orientation. The position of the data to be processed by the monitor is relatively shifted. The principle of moving the position of the data on the monitor by the mouse basically utilizes the simultaneous operation of the X-axis and Y-axis encoders to produce a point movement on a plane. In other words, operating the X-axis encoder or the Y-axis encoder alone can only be used to move the point on the line. The encoder is generally composed of a light-emitting module (such as a light-emitting diode), a blade grid wheel, and a light sensing module. The blade wheel has a mechanical gear-like structure. During operation, the light beam emitted by the light-emitting module is shielded or unshielded by the blade wheel by the rotation of the blade wheel. Wherein, the shielded light beam is not projected to the light sensing module, and the light sensing module generates an OFF (0) signal. On the other hand, the unmasked light beam is received by the light sensing module, and The sensor generates an ON (1) signal. The signals of OFF(0) and ON(1) are sequentially generated to form a sequence of signals. For example, when the blade wheel rotates in a clockwise direction, the sequence signal generated by the sensor is a continuous repetitive signal of 11, 10, 00, 01, 11, 10, 00, 01..., counterclockwise rotation At the time, it is a continuous repetition of 01, 00, 10, 11, 01, 00, 10, 11, 10..., and these sequence signals are used for circuit coding.

In general, the more the number of blades included in the blade wheel, and the smaller the distance between the two sensors, the higher the resolution (in terms of CPR, Count per Round). However, when the angle between adjacent blades of the blade wheel is reduced, that is, as the number of blades increases, the outer diameter of the gate wheel will increase. If it is not desired to increase the outer diameter of the grid wheel, it is necessary to reduce the width of the blade. However, the diffraction of light causes the reduction of the blade width to have its limit. In detail, under the excessive number of blades, the diffraction phenomenon occurs when the light beam passes through the blades of the grid wheel, and the light beam cannot be shielded by the blades of the gate wheel, resulting in two sensings regardless of whether the gate wheel rotates clockwise or counterclockwise. The signals generated by the device are continuous repeated ON (1) signals, and different sequence signals cannot be generated due to the direction in which the mouse slides.

1A and 1B, FIG. 1A is a schematic diagram of a configuration of a light guide type encoder of the prior art, and FIG. 1B is a blade and light sense of the light guide type grid wheel 1' of the light guide type encoder of the prior art. A partial schematic view of the test module 3. In order to overcome the problem of light diffraction, a technique used in the prior art is to focus the emitted light beam through a spherical surface by using a plurality of continuously arranged spherical surfaces as the light-emitting surface of the light-guiding grating wheel 1'. As shown in FIG. 1B, the light sensing module 3 includes the photosensitive wafers S1 and S2 disposed on the same vertical axis, and the light beam emitted by the light guiding grating wheel 1' is focused on the first of the light sensing module 3. The bare sensing area 31 and/or the second sensing area 32. Specifically, the light guide type grating 1' of the light guide type encoder of the prior art is rotated to the first position (1), the second position (2), the third position (3), and the fourth position (4). When, the signals of [1, 1], [0, 1], [1, 0], and [0, 0] are generated separately. However, as can be seen in Figure 1B, the light guide grid wheel 1' of the prior art must utilize two blades to complete the aforementioned set of code sequences comprising four signals.

In summary, in view of the technical means of the above-mentioned prior art, since the light beam inside the light guiding type grating wheel 1' passes through the spherical surface, its width is reduced by the traveling distance due to focusing, so that it is necessary to precisely control the light feeling. The distance between the measuring module 3 and the light guiding grid wheel 1' can ensure that the light sensing module 3 can receive the light beam from the light guiding grid wheel 1' to generate a signal. Moreover, in the prior art, the photosensitive wafers S1 and S2 of the light sensing module 3 are disposed along the same vertical axis. Therefore, the light guiding grating wheel 1' requires two blades to complete a coding timing or sequence [1] , 1], [0, 1], [1, 0], and [0, 0], so that the resolution of the light guide encoder cannot be significantly improved.

Therefore, how to improve the resolution of the light guiding encoder without increasing the size of the grating wheel and the number of blades is still an urgent task in the art.

In order to solve the above technical problem, according to one aspect of the present invention, an optical scanning double-layer light guiding encoder is provided, which comprises a double-layer light guiding grid wheel, a lighting module, and a light sensing module. The light sensing module includes a plurality of sensing elements adjacent to the double-layer light-guiding grating wheel, wherein each of the sensing elements has a bare sensing area, and a plurality of the plurality of sensing elements The bare sensing regions are laterally offset from each other and extend laterally along a plurality of mutually parallel different horizontal lines.

Another embodiment of the present invention provides an optical scanning double-layer light guiding encoder, which comprises a double-layer light guiding type grating wheel, a light emitting module, and a light sensing module. The double-layer light-guiding grid wheel includes a light guiding body and a gear-like structure, wherein the gear-like structure has a plurality of aspherical protrusions. The light emitting module is adjacent to the double layer light guiding grid wheel. An incident light beam generated by the light emitting module enters the double-layer light-guiding grating wheel from the annular light-incident surface to form a parallel light beam or a nearly parallel light projected on the light sensing module. Near parallel beams. Wherein, a beam width of the parallel beam or the near-parallel beam is equal to a width of the light-emitting surface, and a beam width of the parallel beam or the near-parallel beam is a curvature of a vertex surface of the aspherical protrusion To adjust.

According to still another embodiment of the present invention, an optical scanning double-layer optical encoder includes a double-layer light-guiding grating wheel, a light-emitting module, and a light sensing module. The double-layer light-guiding grid wheel includes a light guiding body and a gear-like structure, wherein the gear-like structure has a plurality of protrusions. The light emitting module is adjacent to the double-layer light guiding type grating wheel, and the light sensing module is adjacent to the double layer light guiding type grating wheel. Wherein, the width of each of the protrusions of the gear-like structure is equal to the width of the light sensing module.

The optical scanning type double-layer light guiding encoder provided by the embodiment of the present invention has a bare sensing area and a plurality of bare sensing portions of the plurality of sensing elements through each of the sensing elements. The sensing regions are laterally offset from each other and extend laterally along a plurality of mutually parallel horizontal lines, respectively, so that the parallel or near parallel beams projected on the light sensing module and the sense of exposure of the plurality of sensing elements can be made The measurement areas cooperate with each other to improve the resolution of the encoder without increasing the size of the light-guiding grid wheel and the number of blades. Furthermore, through the above design, the light guiding type encoder provided by the embodiment of the invention can avoid the generation of the diffraction phenomenon of light.

For a better understanding of the features and technical aspects of the present invention, reference should be made to the accompanying drawings.

E‧‧‧Optical scanning double-layer light guide encoder

1‧‧‧Double light guide wheel

1'‧‧‧Light guide wheel

101‧‧‧Lighting body

102‧‧‧ Gear-like structure

1020‧‧‧Aspherical projections

11‧‧‧ ring into the glossy surface

12‧‧‧Circular reflection surface

13‧‧‧Circular illuminating surface

130‧‧‧Aspherical

13a‧‧‧reflecting surface

13b‧‧‧Glossy

2‧‧‧Lighting module

3‧‧‧Light sensing module

31’‧‧‧First sensing element

32'‧‧‧Second sensing element

33'‧‧‧ Third sensing element

34'‧‧‧fourth sensing element

31, 31a~31d‧‧‧First exposed sensing area

32, 32a, 32b‧‧‧Second bare sensing area

33‧‧‧ Third exposed sensing area

34‧‧‧4th bare sensing area

4‧‧‧Raster

41, 41a~41d‧‧‧ first opening

42,42a, 42b‧‧‧ second opening

43‧‧‧ third opening

44‧‧‧fourth opening

5‧‧‧Mirror

S1, S2‧‧‧Photosensitive wafer

a ₁ ‧‧‧ first surface

a ₂ ‧‧‧second surface

a ₃ ‧‧‧ third surface

a ₄ ‧‧‧fourth surface

D‧‧‧projection width

A‧‧‧ aspherical structure

S‧‧‧Spherical structure

L‧‧‧ incident beam

R‧‧·reflected beam

P‧‧‧ parallel beam or near parallel beam

H1, H2, H3, H4‧‧‧ horizontal lines

W, W1, W2, W3, W4, D1, D2, D3, D4‧‧ Width

X‧‧‧Axis

1A is a schematic diagram of a configuration of a light guide encoder of the prior art; FIG. 1B is a schematic diagram of a code guide sequence generated by a conventional light guide encoder; FIG. 2 is an optical scan type double provided by an embodiment of the present invention. FIG. 3 is a schematic diagram of a configuration of an optical scanning double-layer optical encoder according to another embodiment of the present invention; FIG. 4 is an optical scanning dual according to an embodiment of the present invention; FIG. 5 is a top view of a double-layer light-guiding grid wheel of an optical scanning double-layer light guide encoder according to an embodiment of the present invention; FIG. 6 is a cross-sectional view of the double-layer light-guiding grid wheel of the optical scanning double-layer light guiding encoder according to an embodiment of the present invention taken along line VV of FIG. 5; FIG. 7 is an enlarged view of the portion A of FIG. FIG. 8 is a partial schematic view showing a tooth structure of a conventional light guide type encoder; FIG. 9 is a partial schematic view showing a tooth structure of an optical scanning type double light guide encoder according to an embodiment of the present invention; 10 is a partial cross-sectional view of the structure shown in FIG. 11 is another partial cross-sectional view of the structure shown in FIG. 7; FIG. 12 is a double-layer light-guiding grid wheel of the optical scanning double-layer light guide encoder according to the first embodiment of the present invention. A partial schematic diagram of the relationship between a parallel beam or a near-parallel beam and a light sensing module in a position; FIG. 13 is a double layer guide of an optical scanning double-layer light guiding encoder according to a first embodiment of the present invention; A partial schematic diagram of the relationship between a parallel beam or a near-parallel beam and a light sensing module when the light grating wheel is rotated to the second position; FIG. 14 is an optical scanning double layer provided by the first embodiment of the present invention A partial schematic diagram of the relationship between a parallel beam or a near-parallel beam and a light sensing module when the two-layer light guiding grid wheel of the light guiding encoder is rotated to the third position; FIG. 15 is a first embodiment of the present invention A partial schematic diagram of the relationship between a parallel beam or a near-parallel beam and a light sensing module when the double-layer light guiding grid wheel of the optical scanning double-layer optical encoder is rotated to the fourth position; FIG. For the second specific embodiment of the present invention The partial schematic diagram of the relationship between the parallel beam or the near parallel beam and the light sensing module when the double-layer light guiding grating wheel of the optical scanning double-layer light guiding encoder provided by the embodiment is rotated to the first position; FIG. 17 is a parallel beam or near-parallel beam and light sensing module of the optical scanning type double-layer optical encoder of the optical scanning type double-layer optical encoder according to the second embodiment of the present invention when rotated to the second position; A partial schematic diagram of the relationship between the two; FIG. 18 is a parallel light beam or near when the double-layer light guiding grid wheel of the optical scanning double-layer light guiding encoder is rotated to the third position according to the second embodiment of the present invention; A partial schematic diagram of the relationship between the parallel beam and the light sensing module; FIG. 19 is a second embodiment of the optical scanning double-layer light guiding encoder provided by the second embodiment of the present invention A partial schematic diagram of the relationship between a parallel beam or a near-parallel beam and a light sensing module in four positions; FIG. 20 is a grating and light of an optical scanning double-layer light guiding encoder according to a second embodiment of the present invention; Sensing module receiving FIG. 21 is a schematic diagram of a signal generated by a beam after the beam; FIG. 21 is a parallel light beam or near parallel when the double-layer light guiding grating wheel of the optical scanning double-layer light guiding encoder is rotated to the first position according to the third embodiment of the present invention; FIG. 22 is a schematic diagram showing a relationship between a light beam and a light sensing module; FIG. 22 is a schematic diagram of a signal generated by the light sensing module used in FIG. 21 after receiving a light beam; FIG. 23 is an optical diagram of a fourth embodiment of the present invention. A partial schematic diagram of the relationship between a parallel beam or a near-parallel beam and a light sensing module when the double-layer light guiding grid wheel of the scanning double-layer optical encoder is rotated to the first position; and FIG. 24 is FIG. 23 The schematic diagram of the signal generated by the light sensing module after receiving the light beam.

The following is a specific embodiment to illustrate the implementation of the "optical scanning double-layer light guide encoder" disclosed by the present invention, and those skilled in the art can understand the advantages and effects of the present invention from the contents disclosed in the specification. The present invention can be implemented or applied in various other specific embodiments, and various modifications and changes can be made without departing from the spirit and scope of the invention. In addition, the drawings of the present invention are merely illustrative and are not described in terms of actual dimensions. The following embodiments will further explain the related technical content of the present invention, but the disclosure is not intended to limit the technical scope of the present invention.

First, please refer to Figure 2 and Figure 3. FIG. 2 is a schematic diagram of a configuration of an optical scanning double-layer optical encoder E according to an embodiment of the present invention, and FIG. 3 is a schematic diagram of a configuration of an optical scanning double-layer optical encoder E according to another embodiment of the present invention. . The optical scanning double-layer optical encoder E comprises a double-layer light guiding grid wheel 1, a light-emitting module 2, and a light sensing module 3. For example, as shown in FIG. 2, the double-layer light-guiding grid wheel 1, the light-emitting module 2, and the light-sensing module 3 can be disposed at an angle of 90°. In other words, the light-emitting module 2 and the light-sensing module 3 can be disposed at an angle of 90° with respect to the double-layer light-guiding grid wheel 1 . In addition, as shown in FIG. 2, the light-emitting module 2 and the light-sensing module 3 may be disposed on the same side of the double-layer light-guiding grid wheel 1. For example, the light emitting module 2 and the light sensing module 3 can be disposed on the same carrier. As shown in FIG. 3, the optical scanning double-layer optical encoder E provided by the embodiment of the present invention further includes a mirror 5. The mirror 5 is disposed on one side of the double-layer light-guiding grid wheel 1 for reflecting the parallel beam or the near-parallel beam P from the double-layer light-guiding grid wheel 1 to be directed toward the light sensing module 3. The optical scanning double-layer light guiding encoder E of the embodiment of the invention further includes a grating 4 disposed between the double-layer light guiding grating wheel 1 and the light sensing module 3. The grating 4 is an optional member.

Next, please refer to Figures 4 to 6. 4 is a perspective view of a double-layer light guide type grating wheel 1 of an optical scanning double-layer light guide encoder E according to an embodiment of the present invention, and FIG. 5 is an optical scanning double-layer light guide according to an embodiment of the present invention. FIG. 6 is a top view of the double-layer light-guiding grid wheel 1 of the encoder E, and FIG. 6 is a double-layer light-guiding grid wheel 1 of the optical scanning double-layer light guide encoder E according to the embodiment of the present invention. A cross-sectional view of the VV line.

The double-layer light-guiding grid wheel 1 is made of a light-guiding material. For example, the double-layer light-guiding grid wheel 1 can be made of glass, acryl or polycarbonate (PC), or any combination of the above materials. to make. However, the material of the double-layer light guide type grating wheel 1 of the present invention is not limited thereto. The double-layer light-guiding grid wheel 1 includes a light-guiding body 101 and a gear-like structure 102. The light-guiding body 101 has an annular light-incident surface 11 and an annular reflection surface 12 corresponding to the annular light-incident surface 11. The gear-like structure 102 has an annular light-emitting surface 13 composed of a plurality of aspherical surfaces 130 which are sequentially connected and has a center without a center, and the gear-like structure 102 is formed by sequentially connecting a plurality of aspherical protrusions 1020 into a circle. . In the present invention, the aspherical projection may be replaced by a spherical projection. Specifically, the annular light-incident surface 11 is disposed along the outer edge of the double-layer light-guiding grid wheel 1 on the surface of the double-layer light-guiding grid wheel 1 facing the light-emitting module 2 . The annular light incident surface 11 can be a convex lens structure for focusing the incident light beam L generated by the light emitting module 2. The annular reflecting surface 12 is for reflecting the incident light beam L generated by the light-emitting module 2 and focused by the annular light-incident surface 11, thereby generating a reflected light beam R directed toward the annular light-emitting surface 13. Furthermore, the annular reflecting surface 12 is a slope inclined with respect to the axis X of the double-layer light guiding grid wheel 1, and for example, the angle of the inclination may be about 45 degrees. As shown in FIG. 5, the annular reflecting surface 12 can be formed by forming a groove having a triangular cross section on the surface of the double-layer light guiding grating wheel 1, and the depth of the groove is defined by the center of the double-layer light guiding grating wheel 1. Declining outward.

Next, please refer to the content of FIG. 3 and cooperate with FIG. 7 to FIG. 7 is an enlarged view of a portion A of FIG. 3, FIG. 8 is a partial schematic view showing a toothed structure of a conventional encoder, and FIG. 9 is an optical scanning double-layer light guiding encoder according to an embodiment of the present invention. A partial schematic view of the toothed structure, FIG. 10 is a partial cross-sectional view of the structure shown in FIG. 7, and FIG. 11 is another partial cross-sectional view of the structure shown in FIG.

Referring to FIG. 7 first, the annular light-emitting surface 13 is composed of a plurality of aspherical surfaces 130 connected in sequence. The aspherical surface 130 is composed of two reflecting surfaces 13a and a light-emitting surface 13b connected between the two reflecting surfaces 13a. The reflecting surface 13a may be a reflecting plane, and the light emitting surface 13b may be an aspherical emitting surface, such as a hyperboloid, a paraboloid or an elliptical surface.

Next, please refer to FIG. 8 and FIG. 9. As shown in Fig. 8, a conventional light guiding type encoder generally uses a spherical structure S having a spherical center to constitute a light exiting surface of a blade grating wheel in an encoder, so that light is emitted from the spherical structure S and projected on the sensor. However, since the spherical surface itself has a focusing function, the light beam emitted by the spherical structure S is focused, thereby causing the light beams to have different widths at different positions.

Unlike the conventional spherical structure, as shown in FIG. 9, the aspherical structure A does not have a spherical center but has a major axis. The beam emitted by the aspherical structure A, such as a paraboloid, will be a parallel beam or a nearly parallel beam of nearly parallel light. In the embodiment of the present invention, the aspherical structure A, such as a hyperboloid or a paraboloid, is used to form the light-emitting surface 13b. In this way, by forming the annular light-emitting surface 13 by the aspherical surface 130, it is ensured that the light beam exiting the double-layer light-guiding grating wheel 1 by the annular light-emitting surface 13 has a stable width W, so that the stable width W can be obtained. The parallel beam or the near parallel beam cooperates with the light sensing element or the light bare sensing area having a specific width and arrangement, thereby achieving the effect of generating a coded signal with a higher resolution. Specifically, since the light beam leaving the double-layer light guiding grid wheel 1 has a stable width W, the size and arrangement of the bare sensing area of the light sensing element of the light sensing module 3 are controlled, and the control is controlled. The size of the aspherical light guide wheel 1 aspherical surface 130 can effectively improve the resolution of the optical scanning double-layer optical encoder E. Details of the above-described arrangement of the annular light-emitting surface 13 and the bare sensing area of the light sensing element in the light sensing module 3 will be described in detail later.

Referring to FIG. 10, each of the aspherical surfaces 130 may be composed of a first surface a ₁ , a second surface a ₂ , a third surface a _{3 ,} and a fourth surface a ₄ which are sequentially connected. The first surface a ₁ and the fourth surface a ₄ are reflective surfaces 13a, and the second surface a ₂ and the third surface a ₃ connected between the first surface a ₁ and the fourth surface a ₄ together form a light-emitting surface 13b. In the present invention, since the incident angle of the reflected light beam R projected on the reflecting surface 13a is equal to the reflecting angle, the reflected light beam R is reflected toward the inside of the single-layer double-layer light guiding grating wheel 1 via the reflection. In this way, the light-emitting surface 13b (the second surface a ₂ and the third surface a ₃ ) is a portion through which the reflected light beam R passes through the light-emitting surface 13 , and the reflected light beam R passes through the light-emitting surface 13 b to become a parallel beam or near Parallel beam P. On the other hand, if the reflected light beam R is incident on the reflecting surface 13a (the first surface a ₁ or the fourth surface a ₄ ) of the annular light-emitting surface 13, the reflected light beam R cannot be directly emitted through the double-layer light-guiding grating wheel 1.

In addition, the first surface a ₁ , the second surface a ₂ , the third surface a _{3 ,} and the fourth surface a ₄ may have the same vertical projected area. In other words, as shown in FIG. 10, the first surface a ₁ , the second surface a ₂ , the third surface a _{3 ,} and the fourth surface a ₄ may have the same projection width d. In this case, the projection width of the second surface a ₂ and the third surface a ₃ constituting the light-emitting surface 13b will be one-half of the total projection width. However, the configuration of the first surface a ₁ , the second surface a ₂ , the third surface a _{3 ,} and the fourth surface a ₄ may be adjusted according to actual needs. By adjusting the curvature of the light-emitting surface 13b, the width of the parallel light or the near-parallel light P leaving the double-layer light guide type grating wheel 1 can be adjusted. In other words, the beam width of the parallel beam or the near parallel beam P can be adjusted by the curvature of the vertex surface of the aspherical protrusion 1020.

Please refer to FIG. 11. FIG. 11 shows a possible light exit path of the reflected beam R to the aspheric surface 130. The reflected light beam R is reflected toward the reflecting surface 13a (corresponding to the first surface a ₁ shown in FIG. 10), and then is incident on the light emitting surface 13b (corresponding to the second surface a ₂ and the third surface a shown in FIG. 10). ₃ ), and emitted from the aspheric surface 130 as a parallel beam or a near parallel beam P by the light-emitting surface 13b.

With the above design, the reflected light beam R of the embodiment of the present invention can be reflected by the rotation of the double-layer light-guiding grid wheel 1 by the remaining portion of the corresponding aspheric surface 130 (reflecting surface 13a), or through the corresponding A part of the aspherical surface 130 (light-emitting surface 13b) becomes a parallel beam or a near-parallel beam P and is projected by the grating 4 to the light sensing module 3, thereby generating a circuit-coded signal having a high resolution.

Next, please refer to Figure 2 and Figure 3 again. The light-emitting module 2 is disposed below the annular light-incident surface 11 for generating an incident light beam L that is incident on the annular light-incident surface 11. For example, the light emitting module 2 can be at least one light emitting diode. However, the specific implementation of the lighting module 2 is not limited thereto.

As shown in FIG. 2, the light sensing module 3 can be disposed beside the annular light-emitting surface 13 for receiving the parallel beam or the near-parallel beam P emitted by the light-emitting surface 13b of the aspheric surface 130 of the annular light-emitting surface 13. Alternatively, as shown in FIG. 3, the light sensing module 3 may be disposed on one side of the annular light-incident surface 11 of the double-layer light-guiding grid wheel 1 and received by the reflection of the mirror 5 to receive the annular light-emitting surface 13 The parallel beam or the near parallel beam P emitted by the light-emitting surface 13b of the aspheric surface 130.

The embodiment of the light sensing module 3 varies depending on whether or not the grating 4 is present. For example, when the optical scanning double-layer optical encoder E does not include the grating 4, the light sensing module 3 includes a plurality of sensing elements for receiving the parallel beam or the near parallel beam P emitted by the aspheric surface 130. . Specifically, the sensing elements of the sensing module 3 are of a specific size and are arranged on the surface of the light sensing module 3 according to a specific manner for matching the aspheric surface 130 of the double-layer light guiding grid wheel 1 And generate a signal. In an embodiment without the grating 4, the plurality of sensing elements are laterally offset from each other and extend laterally along a plurality of mutually parallel different horizontal lines.

Or, when the optical scanning type double-layer optical encoder E includes the grating 4, the grating 4 is disposed between the double-layer light-guiding grating wheel 1 and the light sensing module 3, and includes a plurality of slits. Open the hole. At this time, the light sensing module 3 is composed of a plurality of long sensing elements, and the slit-shaped opening is a specific area for the bare sensing element, and the light sensing module 3 has a plurality of Bare sensing area.

It is worth noting that in order to achieve the technical effect of improving the resolution of the optical scanning double-layer optical encoder E, it is necessary to control the widths of the plurality of sensing elements and the bare sensing regions of the sensing elements to be double-layered The width of the aspherical projection 1020 of the light-guiding grid wheel 1 and the width of the light-emitting surface 13b thereof cooperate with each other. In this way, the optical scanning double-layer optical encoder E of the embodiment of the present invention can use the single aspherical protrusion 1020 to generate a complete coding sequence by using the single aspherical protrusion 1020 (for example, only one transmission at a time). An aspherical projection 1020 produces signals of [0, 0], [0, 1], [1, 0], and [1, 1]. The detailed means and parameters of the above control will be described in detail in the following specific embodiments.

In the present invention, the number of sensing elements and bare sensing regions included in the light sensing module 3 can be adjusted according to practice. For example, as shown in FIGS. 12 to 15 , the light sensing module 3 includes a first sensing element 31 ′ and a second sensing element 32 ′ disposed in parallel with each other for receiving a parallel beam emitted by the aspheric surface 130 . Or near parallel beam P. The light sensing module 3 can generate signals of [0, 0], [0, 1], [1, 1], and [1, 0] according to the state in which the parallel beam or the near parallel beam P is received. In other words, two ² signals can be generated using two sensing elements. In addition, as shown in FIGS. 21 and 23, the light sensing module 3 may also include three or four sensing elements, and each of the sensing elements has one or more bare feelings exposed by the openings of the grating 4. Measuring area.

In the above, further, when the incident light beam L generated by the light-emitting module 2 enters the double-layer light-guiding grating wheel 1 from the annular light-incident surface 11, the incident light beam L passes through the reflection of the annular reflection surface 12 to form a reflection. a light beam R, wherein the reflected light beam R passes through the rotation of the double-layer light-guiding grid wheel 1 to pass through a portion of the corresponding aspheric surface 130 (ie, the light-emitting surface 13b) to form a parallel beam or a near-parallel beam P, or is corresponding The remaining portion of the aspherical surface 130 (i.e., the reflective surface 13a) is reflected. Therefore, the parallel beam or near-parallel beam P emitted by the double-layer light guiding grid wheel 1 can be received by the light sensing module 3, thereby generating a sequence signal for circuit coding.

Now, the operation of the sequence signal generated by the optical scanning type double-layer optical encoder E of the embodiment of the present invention will be described in detail.

 [First embodiment]  

Referring to FIGS. 12 to 15 , FIGS. 12 to 15 respectively illustrate the double-layer light-guiding grid wheel 1 of the optical scanning double-layer light guiding encoder E according to the first embodiment of the present invention. In the second, third and fourth positions, a partial schematic diagram of the relationship between the parallel beam or the near parallel beam P and the light sensing module 3.

Specifically, as shown in FIG. 12, the light sensing module 3 includes an elongated first sensing element 31' and a second sensing element 32'. The two sensing elements have the same width D1, and The two ends of the electrodes are aligned with each other such that the light sensing module 3 also has a width D1. A grating 4 having a width greater than D1 is further disposed between the light sensing module 3 and the double-layer light guiding grid wheel 1 for shielding a specific area of the first sensing element 31' and the second sensing element 32' and exposing Other unobstructed areas. The first opening 41 and the second opening 42 included in the grating 4 respectively expose the first bare sensing region 31 of the first sensing element 31 ′ and the second bare sensing region 32 of the second sensing element 32 ′. . In this embodiment, the first opening 41 and the second opening 42 have a width of 1/4 D1, so the first bare sensing area 31 and the second bare sensing area 32 exposed by the same have the same 1/4D1 width. The first bare sensing region 31 and the second bare sensing region 32 are laterally offset from each other and extend laterally along different horizontal lines H1 and H2 parallel to each other.

In the embodiment of the present invention, the width of the aspherical protrusion 1020 is the same as the width D1 of the light sensing module 3, and therefore, each aspherical surface 130 of the double-layer light guiding grid wheel 1 can be sequentially corresponding to The first sensing element 31' and the second sensing element 32' constitute a light sensing module 3, thereby achieving the effect of generating a complete set of coding sequences through only a single aspheric surface 130. In addition, in the first embodiment, the width W1 of the parallel beam or the near parallel beam P emitted by the light-emitting surface 13b is greater than or equal to one-half of the width D1 of the light sensing module 3, that is, W1≧1/ 2D1. 11 to 15 are plotted at a ratio of W1 = 1/2D1. In this way, when the light-emitting surface 13b of the aspheric surface 130 is turned to the position corresponding to the first light bare sensing area 31 and the second light bare sensing area 32 as the double-layer light-guiding grid wheel 1 rotates ( That is, in the state shown in FIG. 14, the parallel light beam or the near parallel light beam P is simultaneously projected onto the first light sensing module 31 and the second light sensing module 32. Next, please refer to FIGS. 12 to 15 in order, and a detailed manner of generating a signal when the light guide type squeeze wheel 1 is rotated to a different position will be described.

First, as shown in FIG. 12, the double-layer light guide type grating wheel 1 is located at the first position. At this time, the first bare sensing region 31 and the second bare sensing region 32 of the light sensing module 3 respectively correspond to the fourth surface a _{4 of} one of the aspheric surfaces 130 of the double light guiding grating wheel 1 and The first surface a _{1 of the} next aspherical surface 130. Since the first surface a ₁ and the fourth surface a _{4 are the} same as the reflecting surface 13a, the reflected light beam R directed to the first surface a ₁ and the fourth surface a ₄ is reflected by the reflecting surface 13a, so as to correspond to the fourth surface a, respectively. ₄ and the first bare sensing region 31 and the second bare sensing region 32 of the first surface a _{1 do} not receive the beam signal, thereby causing the light sensing module 3 to generate a signal of [0, 0].

Next, referring to FIG. 13, the double-layer light guide type grating wheel 1 is rotated to the second position. The first bare sensing region 31 and the second bare sensing region 32 of the light sensing module 3 respectively correspond to the first surface a ₁ and the second surface of one of the aspheric surfaces 130 of the double light guiding grating wheel 1 a ₂ . The first surface a ₁ is the reflecting surface 13a. Therefore, the reflected light beam R directed to the first surface a ₁ is reflected by the reflection toward the inside of the double-layer light guiding grid wheel 1 and cannot be directly separated from the light guiding grating by the reflecting surface 13a. 1. On the other hand, the reflected light beam R directed to the second surface a ₂ passes through the aspherical surface 130 into a parallel beam or a near parallel beam P and is incident on the second bare sensing region 32 corresponding to the second surface a ₂ . Accordingly, the light sensing module 3 generates a signal of [0, 1]. Further, although the reflected light beam into a parallel beam by R may third surface ₃ A or near parallel beam P emitted by the aspherical surface 130, the third surface ₃ does not correspond to the A sensing module sensing any of a bare 3 The area is blocked by the grating 4, so that the parallel beam or the near parallel beam P of this portion does not affect the signal generated by the light sensing module.

Next, referring to FIG. 14, the double-layer light guide type grating wheel 1 continues to rotate to the third position. The first bare sensing region 31 and the second bare sensing region 32 of the light sensing module 3 respectively correspond to the second surface a ₂ and the third surface of one of the aspheric surfaces 130 of the double light guiding grating wheel 1 a ₃ . The reflected light beam R is incident on the aspherical surface 130, and passes through the light-emitting surface 13b composed of the second surface a ₂ and the third surface a ₃ to become a parallel light beam or a near-parallel light beam P to leave the double-layer light guide type grating wheel 1. The parallel light beam or the near parallel light beam P exiting the double-layer light guide grating wheel 1 is simultaneously incident on the first bare sensing region 31 and the second light bare sensing region 32 of the light sensing module 3, and thus, the light sensing Module 3 produces a signal of [1, 1].

Finally, referring to FIG. 15, the double-layer light guide grid wheel 1 continues to rotate to the fourth position. At this time, the first bare sensing region 31 and the second bare sensing region 32 of the light sensing module 3 respectively correspond to the third surface a _{3 of} one of the aspheric surfaces 130 of the double-layer light guiding grid wheel 1 and The fourth surface a ₄ . The reflected light beam R directed to the third surface a ₃ is received by the first bare sensing region 31 through the third surface a ₃ into a parallel beam or a near parallel beam P. However, since the fourth surface a ₄ is the reflecting surface 13a, the reflected light beam R directed to the fourth surface a ₄ is reflected by the fourth surface a ₄ and cannot be separated from the fourth surface a _{4 by the} double-layer light guiding grating wheel 1. Therefore, the second bare sensing region 32 corresponding to the fourth surface a ₄ at this time does not receive the parallel beam or the near parallel beam P. Accordingly, when the double-layer light guide type grating wheel 1 is in the fourth position, the light sensing module 3 generates a signal of [1, 0].

As described above, when the double-layer light-guiding grid wheel 1 is rotated to each position, the design of the reflective surface 13a and the light-emitting surface 13b in the aspheric surface 130 of the double-layer light-guiding grid wheel 1 is more important. With the first bare sensing region 31 and the second bare sensing region 32 in the light sensing module 3 and the size design of the aspheric surface 130, a single aspheric surface 130 can be used to generate 2 ² = 4 sensing signals. The resolution of the light guide encoder E is greatly increased.

 [Second embodiment]  

16 to 20, FIG. 16 to FIG. 19 are respectively a two-layer light guiding grid wheel 1 of an optical scanning double-layer light guiding encoder E according to a second embodiment of the present invention. A partial schematic diagram of the relationship between the parallel beam or the near-parallel beam P and the light sensing module 3 from one position (1) to the fourth position (4), and FIG. 20 is connected to the light sensing module in this embodiment. 3 Schematic diagram of the signal generated after receiving the beam.

In FIGS. 16 to 19, the first sensing element 31' and the second sensing element 32' of the light sensing module 3 are exposed by the first opening 41 and the second opening 42 of the grating 4, respectively, to expose the first bare The sensing area 31 and the second bare sensing area 32. The first bare sensing region 31 and the second bare sensing region 32 are divided into a plurality of coding regions, and the width W2 of the parallel beam or near-parallel beam P is less than or equal to the width of the coding region. Referring to FIG. 16, the first bare sensing region 31 and the second bare sensing region 32 respectively include two coding regions having a width of 1/4D2.

In other words, in the second embodiment, the width W2 of the parallel beam or the near parallel beam P emitted by the light exit surface 13b is less than or equal to that of the first sensing element 31' and the second sensing element 32'. The light sensing module 3 has a width D2 of a quarter, that is, W2 ≦ 1/4D2. In Figs. 16 to 19, the ratio is plotted as W2 = 1/4D2. In addition, the widths of the first bare sensing region 31 and the second bare sensing region 32 in this embodiment are twice the width W2 of the parallel beam or the near parallel beam P, that is, the first bare sensing region 31 and the first The two bare sensing regions 32 each have a width of 1/2 D2. Furthermore, the first bare sensing area 31 and the second bare sensing area 32 are misaligned with each other, that is, the first bare sensing area 31 and the second bare sensing area 32 are misaligned with each other in the directions of different horizontal lines H1 and H2. /4D2 width.

First, as shown in Fig. 16, the double-layer light guide type grating wheel 1 is located at the first position (1). At this time, neither the first light bare sensing area 31 nor the second light bare sensing area 32 corresponds to the second surface a ₂ and the third surface as the light exiting surface 13 b which are emitted by the parallel light beam or the non-parallel light beam P. The surface a ₃ , therefore, as shown in FIG. 20 , in the first position (1), the light sensing module 3 does not receive the beam signal, but generates a signal of [0, 0].

Next, referring to FIG. 17, when the double-layer light guide type grating wheel 1 is rotated to the second position (2), the first light bare sensing area 31 corresponds to the double-sided light-guide type grating wheel as the reflecting surface 13a. The first surface a ₁ and the fourth surface a _{4 of the} previous aspherical surface 130 do not receive the beam signal. In addition, the parallel beam or the near parallel beam P emitted from the second surface a ₂ and the third surface a _{3 of the} double-layer light guiding grid wheel 1 is incident on the light sensing module 3 and projected on the second slit 42. A portion of the bare second light bare sensing region 32. Therefore, as shown in FIG. 20, when the double-layer light guide type grating wheel 1 is located at the second position (2), the light sensing module 3 generates a signal of [0, 1].

Next, referring to FIG. 18, the double-layer light guide type grating wheel 1 is rotated to the third position (3). A parallel beam or a near parallel beam P emitted from the second surface a ₂ and the third surface a _{3 of the} double-layer light guiding grid wheel 1 is incident on the light sensing module 3 and projected on the first slit 41 The first light bare sensing region 31 and a portion of the second light bare sensing region 32 exposed by the second slit 42. Therefore, as shown in FIG. 20, when the double-layer light guide type grating wheel 1 is located at the third position (3), the light sensing module 3 generates a signal of [1, 1].

Finally, referring to FIG. 19, the double-layer light-guiding grid wheel 1 continues to rotate to the fourth position (4). At this time, the parallel beam or the near parallel beam P emitted from the second surface a ₂ and the third surface a _{3 of the} double-layer light guiding grid wheel 1 is incident on the light sensing module 3 and projected on the first slit. 41 part of the bare first light bare sensing area 31. At this time, the second light bare sensing region 32 corresponds to the fourth surface a ₄ as the reflecting surface 13a in the double-layer light guiding grating wheel, and the first surface a _{1 of the} next aspheric surface 130, and thus does not receive To the beam signal. Therefore, as shown in FIG. 20, when the double-layer light guide type grating wheel 1 is at the fourth position (4), the light sensing module 3 generates a signal of [1, 0].

As described above, the double-layer light-guiding grid wheel 1 can pass through the design of the reflective surface 13a and the light-emitting surface 13b of the aspheric surface 130 of the double-layer light-guiding grid wheel 1 when rotated to each position, and cooperate with the light. The first bare sensing area 31 and the second bare sensing area 32 of the sensing module 3 can simultaneously generate 2 ² = 4 sensing signals. Specifically, by adjusting the width W2 of the parallel beam or the near parallel beam P to be less than or equal to the width D2 of the light sensing module 3 composed of the first sensing element 31' and the second sensing element 32' ( At the same time, it is a quarter (W2 ≦ 1/4D2) of the width of the aspherical projection 1020, and the resolution of the light guide encoder E can be increased.

 [Third embodiment]  

21 and 22 further illustrate a schematic diagram of generating an encoded signal by the optical scanning double-layer optical encoder E according to the third embodiment of the present invention. Specifically, FIG. 21 is a second embodiment of the optical scanning double-layer light guide encoder E of the optical double-layer light guide encoder 1 according to the third embodiment of the present invention, in a first position (1), and a parallel beam or near A partial schematic diagram showing the relationship between the parallel beam P and the light sensing module 3, and FIG. 22 is a schematic diagram of the signal generated by the light sensing module 3 used in FIG. 21 after receiving the beam.

Different from the previous embodiment, in this embodiment, the light sensing module 3 is composed of a first sensing component 31', a second sensing component 32', a third sensing component 33', and a fourth sensing. The element 34' is constructed and has the same width D3. Through the first opening 41, the second opening 42, the third opening 43 and the fourth opening 44 of the grating 4, the first bare sensing area 31 and the second bare sensing area 32 which are mutually displaced are respectively exposed. The third bare sensing area 33 and the fourth bare sensing area 34. The first bare sensing region 31, the second bare sensing region 32, the third bare sensing region 33, and the fourth bare sensing region 34 are divided into a plurality of encoding regions, and the width W3 of the parallel beam or the near parallel beam P Is less than or equal to the width of the coding area. Referring to FIG. 21, the bare sensing regions respectively include four coding regions having a width of 1/8D2.

In other words, in the specific embodiment, the widths of the first bare sensing region 31, the second bare sensing region 32, the third bare sensing region 33, and the fourth bare sensing region 34 are 1/2D3. In addition, the first bare sensing area 31, the second bare sensing area 32, the third bare sensing area 33, and the fourth bare sensing area 34 are offset from each other by 1/8D3 in the directions of different horizontal lines H1, H2, H3, and H4. The width.

The width W3 of the parallel beam or the near parallel beam P emitted by the aspherical surface 130 is less than or equal to one eighth of the width D3 of the light sensing module, that is, W3≦1/8D3. Figure 21 is a graph of W3 = 1/8D3. The same as the previous embodiment, the width of the aspherical projection 1020 is the same as the width D3 of the light sensing module 3. For example, in the state shown in FIG. 21, the flat beam or the near-flat beam P is projected on the light sensing module 3 and causes the light sensing module 3 to generate a signal of [0, 0, 0, 0]. In the third embodiment, the signal generated by the light sensing module 3 according to the rotational position of the double light guiding grid wheel 1 is as shown in FIG. Therefore, in this embodiment, the optical scanning double-layer optical encoder E can generate 2 ³ = 8 signals.

 [Fourth embodiment]  

Finally, please refer to FIG. 23 and FIG. 24. FIG. 23 is a schematic diagram of a double-layer light-guiding grid wheel of an optical scanning double-layer light guide encoder E according to another embodiment of the present invention, at a first rotation angle, and a reflected beam and a light sensing module. A partial schematic diagram of the relationship; and FIG. 24 is a schematic diagram of the signal generated by the light sensing module used in FIG. 23 after receiving the light beam.

Referring to FIG. 23, in this embodiment, the optical sensing module 3 of the optical scanning double-layer optical encoder E includes a first sensing element 31' and a second sense that are arranged in parallel and are elongated. The measuring element 32' and the third sensing element 33' have a width D4 of the light sensing module 3 formed by the sensing element. The first opening 41a~41d of the grating 4 exposes a specific area of the first sensing element 31' to form the first bare sensing area 31a~31d, and the second opening 42a, 42b exposes the specific part of the second sensing element 32' A second bare sensing region 32a, 32b is formed in the region, and the third opening 43 exposes a specific region of the third sensing element 33' to form a third bare sensing region 33. The dimensions of each bare sensing area are as shown.

Specifically, the first bare sensing regions 31a 31d, the second bare sensing regions 32a, 32b, and the third bare sensing region 33 are divided into a plurality of encoding regions, and the width W4 of the parallel beam or the near parallel beam P is Is less than or equal to the width of the coding area. Referring to FIG. 23, the first bare sensing regions 31a 31d, the second bare sensing regions 32a, 32b, and the third bare sensing region 33 respectively include four, two, and one encoding region having a width of 1/8D2.

In this embodiment, the width W4 of the parallel beam or near-parallel beam P is less than or equal to one-eighth of the width D4 of the light sensing module 3, that is, W4≦1/8D4. As with the previous embodiment, the width of the aspherical projection 1020 is equal to the width D4 of the light sensing module 3. For example, in the state shown in FIG. 23, the flat beam or the near-flat beam P is projected on the light sensing module 3 and causes the light sensing module 3 to generate a signal of [0, 0, 0]. In the fourth embodiment, the signal generated by the light sensing module 3 according to the rotational position of the double light guiding grid wheel 1 is as shown in FIG. In a specific embodiment, the optical scanning double layer light guide encoder E can generate 2 ³ = 8 signals.

 [Effective effect of the embodiment]  

In summary, the optical scanning double-layer optical encoder E provided by the embodiment of the present invention may have a bare sensing area and multiple sensing through each sensing element. The plurality of bare sensing regions of the component are laterally offset from each other and extend laterally along a plurality of mutually parallel different horizontal lines, so that the parallel beam or the near parallel beam P projected on the light sensing module 3 can be The bare sensing regions of the sensing elements cooperate with each other, and the resolution of the light guiding encoder E is improved without increasing the size of the double-layer light guiding grid wheel 1 and the number of aspherical projections 1020. In addition, the optical scanning double-layer optical encoder E provided by the embodiment of the present invention can adjust the beam width of the parallel beam or the near-parallel beam P by adjusting the curvature of the vertex surface of the aspherical protrusion 1020, or The width of each of the aspherical projections 1020 of the gear-like structure 102 is designed to be equal to the width of the light sensing module 3, thereby helping to achieve the desired resolution.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Therefore, equivalent technical changes made by using the present specification and the contents of the drawings are included in the protection scope of the present invention. .

Claims (15)

An optical scanning double-layer light guiding encoder comprising: a double-layer light guiding type grating wheel; a lighting module, the light emitting module is adjacent to the double-layer light guiding type grating wheel; and a light sensing mode The light sensing module includes a plurality of sensing elements adjacent to the double-layer light-guiding grating wheel, wherein each of the sensing elements has a bare sensing area, and a plurality of the sensing elements The plurality of bare sensing regions are laterally offset from each other and extend laterally along a plurality of mutually parallel different horizontal lines; wherein the double-layer light-guiding grating wheel has an annular light-incident surface and one corresponding to the circular light-integrating light The annular reflecting surface of the surface and the two annular light emitting surfaces, and each of the annular light emitting surfaces is composed of a plurality of aspherical surfaces which are sequentially connected and have a main axis. The optical scanning type double-layer light guiding encoder according to claim 1, further comprising a grating disposed between the double-layer light guiding type grating wheel and the light sensing module, The grating includes a plurality of slits for respectively exposing a plurality of the bare sensing regions. The optical scanning type double-layer light guiding encoder according to claim 1, wherein the double-layer light guiding type grating wheel comprises a light guiding body and two gear-like structures, and the light guiding body has the annular inlet a smooth surface and the annular reflecting surface corresponding to the annular light incident surface, each gear-like structure having the annular light-emitting surface composed of a plurality of aspherical surfaces sequentially connected and having a main axis, and each gear shape The structure is composed of a plurality of aspherical projections connected in sequence to form a circle. The optical scanning type double-layer light guiding encoder according to claim 3, wherein an incident light beam generated by the light emitting module enters the double-layer light guiding type grating wheel from the annular light incident surface, and the incident The light beam is reflected by the annular reflecting surface to form a reflected light beam, and the reflected light beam passes through each of the annular light exiting surfaces to form a parallel beam or a near parallel light projected on the light sensing module. Parallel beams. The optical scanning type double-layer light guiding encoder according to claim 4, wherein the reflected light beam passes through the rotation of the double-layer light guiding type grating wheel to pass through a part of the corresponding aspheric surface or is phased The remaining portion of the corresponding aspheric surface is reflected. The optical scanning double-layer light guiding encoder according to claim 5, wherein the aspheric surface of the double-layer light guiding grating wheel is composed of two reflecting surfaces and one connected to the two reflecting surfaces. The light-emitting surface between the two. The optical scanning type double-layer light guiding encoder according to claim 6, wherein a part of the reflected light beam passes through the rotation of the double-layer light guiding type grating wheel to pass through the corresponding light-emitting surface. The optical scanning double-layer light guiding encoder of claim 6, wherein a portion of the reflected light beam is reflected by the reflecting surface. The optical scanning type double-layer light guiding encoder according to claim 6, wherein a beam width of the parallel beam or the near-parallel beam is equal to a width of the light-emitting surface. The optical scanning type double-layer light guiding encoder according to claim 6, wherein a beam width of the parallel beam or the near-parallel beam is adjusted by a curvature of a vertex surface of the aspherical convex portion. The optical scanning double-layer light guiding encoder of claim 10, wherein the bare sensing region of each of the sensing elements is divided into a plurality of coding regions, the parallel beam or the near parallel The beam width of the beam will be less than or equal to the width of the coding region. The optical scanning double-layer light guiding encoder according to claim 3, wherein a width of each of the aspherical projections of each of the gear-like structures is equal to a width of the light sensing module. An optical scanning double-layer light guiding encoder comprising: a double-layer light guiding type grating wheel, the double-layer light guiding type grating wheel comprises a light guiding body and two gear-like structures, wherein each gear-like structure a plurality of aspherical protrusions; a light emitting module, the light emitting module being adjacent to the double light guiding grating wheel; a light sensing module, the light sensing module is adjacent to the double light guiding grating wheel; wherein an incident light beam generated by the light emitting module passes through the double light guiding grating wheel to form Projecting at least one parallel beam or at least one near-parallel beam of the near-parallel light on the light sensing module; wherein a beam width of the parallel beam or the near-parallel beam is equal to a width of the light-emitting surface, and The beam width of the parallel beam or the near-parallel beam is adjusted by the curvature of the vertex surface of the aspherical projection. An optical scanning double-layer light guiding encoder comprising: a double-layer light guiding type grating wheel, the double-layer light guiding type grating wheel comprises a light guiding body and two gear-like structures, wherein each gear-like structure Having a plurality of protrusions; a light-emitting module, the light-emitting module is adjacent to the double-layer light-guiding grid wheel; and a light-sensing module, the light-sensing module is adjacent to the double-layer light guide a grid wheel; wherein each of the protrusions of each of the gear-like structures has a width equal to a width of the light sensing module. The optical scanning type double-layer light guiding encoder according to claim 14, wherein the protruding portion is an aspherical convex portion or a spherical convex portion.