CN113661376A - Encoder for encoding a video signal - Google Patents
Encoder for encoding a video signal Download PDFInfo
- Publication number
- CN113661376A CN113661376A CN201980094996.8A CN201980094996A CN113661376A CN 113661376 A CN113661376 A CN 113661376A CN 201980094996 A CN201980094996 A CN 201980094996A CN 113661376 A CN113661376 A CN 113661376A
- Authority
- CN
- China
- Prior art keywords
- light
- encoder
- light receiving
- receiving element
- mounting surface
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229920005989 resin Polymers 0.000 claims abstract description 63
- 239000011347 resin Substances 0.000 claims abstract description 63
- 239000000758 substrate Substances 0.000 claims abstract description 48
- 230000003287 optical effect Effects 0.000 claims description 53
- 239000011521 glass Substances 0.000 claims description 6
- 239000003822 epoxy resin Substances 0.000 claims description 4
- 229920000647 polyepoxide Polymers 0.000 claims description 4
- 230000001678 irradiating effect Effects 0.000 claims description 2
- LNEPOXFFQSENCJ-UHFFFAOYSA-N haloperidol Chemical compound C1CC(O)(C=2C=CC(Cl)=CC=2)CCN1CCCC(=O)C1=CC=C(F)C=C1 LNEPOXFFQSENCJ-UHFFFAOYSA-N 0.000 claims 1
- 238000001514 detection method Methods 0.000 description 24
- 238000009826 distribution Methods 0.000 description 14
- 238000000034 method Methods 0.000 description 14
- 238000010586 diagram Methods 0.000 description 12
- 239000000463 material Substances 0.000 description 9
- 230000010363 phase shift Effects 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 239000004593 Epoxy Substances 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 230000008602 contraction Effects 0.000 description 4
- 238000003708 edge detection Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- 238000004904 shortening Methods 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/347—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells using displacement encoding scales
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/30—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring angles or tapers; for testing the alignment of axes
Abstract
The encoder includes a light-emitting/receiving module package (3), and the light-emitting/receiving module package (3) includes a package substrate (30) and a light-transmitting resin (33) covering a mounting surface (30a) of the substrate. The light-transmitting resin (33) has: a 1 st portion (33a) that covers a region of the mounting surface (30a) where the light-emitting element (31) is provided; and a 2 nd portion (33b) that covers a region of the mounting surface (30a) where the light-receiving element (32) and a bonding wire (35) that connects the light-receiving element (32) and the substrate are provided. The thickness of the light-transmitting resin (33) in the direction perpendicular to the mounting surface (30a) is thinner in at least a part of the 2 nd region (33b) than the 1 st region (33a), or the length of the light-transmitting resin (33) in the direction parallel to the mounting surface (30a) and perpendicular to the direction in which the light-emitting element (31) and the light-receiving element (32) are arranged is shorter in at least a part of the 2 nd region (33b) than the 1 st region (33 a).
Description
Technical Field
The present invention relates to an encoder for detecting a rotation angle of a measurement object.
Background
An optical rotary encoder is an encoder that calculates the rotation angle of a scale based on an optical signal incident from the scale. The light emitting element that irradiates light to the scale and the light receiving element that receives light from the scale are covered with a light-transmissive resin, and are thereby protected from the external environment. In addition, the bonding wire connecting the light receiving element and the substrate is protected by the light transmissive resin together with the light receiving element. Generally, since the thermal expansion rates are different between the materials of the light transmissive resin and the bonding wire, the bonding wire may be subjected to stress due to expansion or contraction of the light transmissive resin due to a temperature change. The bonding wire is sometimes subjected to repeated stress and broken.
Patent document 1 discloses a light-emitting device including a light-transmissive resin covering a light-emitting element provided on a base substrate, and a through hole through which a bonding wire connected to the light-emitting element is inserted is provided in the base substrate. According to the technique of patent document 1, the amount of light-transmissive resin around the bonding wire is reduced, thereby reducing the stress to which the bonding wire is subjected due to a temperature change.
Patent document 1: japanese patent laid-open publication No. 2012-94612
Disclosure of Invention
In the encoder, the number of bonding wires increases as the number of light receiving elements increases for highly accurate calculation of the rotation angle. When the technique of patent document 1 is applied to the bonding wires connected to the light receiving element, the number of through holes increases as the number of bonding wires increases in the substrate on which the light receiving element is mounted. As the number of through holes increases, the size of the package formed of the light transmissive resin increases, and therefore, it is difficult to miniaturize the encoder. Further, the larger the number of through holes, the more complicated the processing at the time of manufacturing the encoder becomes. Therefore, according to the technique of patent document 1, there is a problem that it is difficult to reduce breakage of the bonding wire with a structure that is small and can be easily processed.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an encoder capable of preventing breakage of a bonding wire connecting a light receiving element and a substrate with a small and easily processable structure.
In order to solve the above problems and achieve the object, an encoder according to the present invention includes: a scale having an optical pattern; and a module package having a substrate on which a light emitting element for irradiating light to the scale and a light receiving element having a light receiving surface on which light from the scale is incident are mounted, and an optically transmissive resin covering a mounting surface on which the light emitting element and the light receiving element are mounted in the substrate. The light-transmissive resin has a 1 st portion covering a region of the mounting surface where the light-emitting element is provided, and a 2 nd portion covering a region of the mounting surface where the light-receiving element and the bonding wire connecting the light-receiving element and the substrate are provided. The thickness of the light-transmissive resin in the direction perpendicular to the mounting surface is smaller in at least a part of the 2 nd portion than in the 1 st portion, or the length of the light-transmissive resin in the direction parallel to the mounting surface and perpendicular to the direction in which the light-emitting elements and the light-receiving elements are arranged is shorter in at least a part of the 2 nd portion than in the 1 st portion.
ADVANTAGEOUS EFFECTS OF INVENTION
The encoder according to the present invention has an effect that breakage of a bonding wire connecting a light receiving element and a substrate can be prevented by a small-sized and easily processable structure.
Drawings
Fig. 1 is a diagram showing a configuration of an encoder according to embodiment 1 of the present invention.
Fig. 2 is an oblique view of a module package provided in the encoder shown in fig. 1.
Fig. 3 is a sectional view of a module package provided in the encoder shown in fig. 1.
Fig. 4 is a plan view of a module package included in the encoder shown in fig. 1.
Fig. 5 is a block diagram showing a configuration of an angle calculation unit included in the encoder shown in fig. 1.
Fig. 6 is a diagram showing an example of a signal waveform of a signal input to the light amount distribution correcting unit included in the angle calculating unit shown in fig. 5.
Fig. 7 is a diagram showing an example of a signal waveform after correction in the light amount distribution correction unit included in the angle calculation unit shown in fig. 5.
Fig. 8 is a diagram for explaining a method of calculating a rough absolute rotation angle from the signal of the signal waveform shown in fig. 7.
Fig. 9 is a diagram for explaining a method of calculating a high-precision absolute rotation angle from a rough absolute rotation angle explained by reference to fig. 8.
Fig. 10 is a sectional view of a module package included in an encoder according to embodiment 2 of the present invention.
Fig. 11 is a plan view of a module package included in the encoder shown in fig. 10.
Fig. 12 is a perspective view of a module package included in an encoder according to embodiment 3 of the present invention.
Fig. 13 is a plan view of a module package included in the encoder shown in fig. 12.
Detailed Description
Hereinafter, an encoder according to an embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments. In the drawings shown below, the scale of each element may be different from the actual scale, and the same applies to each drawing. In the drawings shown below, elements shown in cross-section may not be hatched for easy viewing of the drawings.
Embodiment 1.
Fig. 1 is a diagram showing a configuration of an encoder according to embodiment 1 of the present invention. The encoder 1 detects the rotation angle of the rotating body as the object to be measured. The encoder 1 is an optical rotary encoder that calculates the rotation angle of the scale based on an optical signal incident from the scale, and is an absolute encoder that detects the absolute rotation angle.
The encoder 1 includes: an optical scale 2 which is a scale having an optical pattern 20; a light-emitting and light-receiving module package 3 having a light-emitting function and a light-receiving function; and a control unit 4 that controls the encoder 1. The optical scale 2 is coupled to a rotating shaft 5 included in a rotating device such as a motor. The optical scale 2 rotates together with the rotation shaft 5. In fig. 1, illustration of the rotating device is omitted.
A circular plate material is used for the optical scale 2. The optical pattern 20 is provided in an annular region that is an outer peripheral portion of the circular shape of the optical scale 2. The optical pattern 20 has reflective portions 21 and non-reflective portions 22 alternately arranged in a direction along the outer periphery of the circular shape. The reflection portion 21 is a portion that reflects light incident from a light emitting element described later toward the light emitting/receiving module package 3. The non-reflection portion 22 is a portion that absorbs or scatters light incident from the light emitting element.
The plurality of reflective portions 21 and the plurality of non-reflective portions 22 each have various widths in a direction along the outer periphery. If the light emitting element irradiates light to the optical pattern 20 that is rotating, reflection for a time corresponding to the width of the reflection portion 21 and non-reflection for a time corresponding to the width of the non-reflection portion 22 are repeated in the optical pattern 20. A light receiving element described later detects light reflected by the reflection unit 21. The intensity of the light detected by the light receiving element is modulated according to the arrangement pattern of the reflective portions 21 and the non-reflective portions 22.
The arrangement pattern of the reflective portions 21 and the non-reflective portions 22 is set to give a characteristic to the rotation angle of the optical scale 2. As described above, the optical scale 2 has the optical pattern 20 unique to the rotation angle. For example, an approximately random symbol pattern such as an M series is used for the optical pattern 20.
As the plate material constituting the optical scale 2, for example, a metal base material such as stainless steel is used. The non-reflective portion 22 is formed by plating the surface of the metal base material. The reflection portion 21 is formed by mirror-finishing the surface of the metal base material. The reflection portion 21 may be formed by a method other than mirror finishing. The non-reflection portion 22 may be formed by a method other than plating.
The light emitting and receiving module package 3 emits light toward the optical scale 2. The light receiving and projecting module package 3 detects light reflected by the optical scale 2. The light receiving and projecting module package 3 outputs a signal corresponding to the detected light to the control unit 4. The control unit 4 includes: an angle calculation unit 41 that calculates the absolute rotation angle of the optical scale 2; and a light emission amount adjusting unit 42 that adjusts the amount of light emitted from the light projecting/receiving module package 3.
The angle calculation unit 41 calculates the absolute rotation angle of the optical scale 2 based on a signal output from a light receiving element included in the light receiving and projecting module package 3. The absolute rotation angle obtained by the angle calculation unit 41 corresponds to the rotation position of the rotating shaft 5. As described above, the angle calculation unit 41 obtains the rotational position of the rotary shaft 5 based on the signal corresponding to the encoded optical pattern 20. The angle calculation unit 41 outputs position data 43, which is data indicating the rotational position of the rotary shaft 5, as a result of the calculation of the absolute rotation angle to an external device. The light emission amount adjusting section 42 adjusts the light emission amount of the light emitting element based on the signal output from the light receiving element. The light emitting element and the light receiving element are described later.
As described above, the encoder 1 calculates the absolute rotation angle by the angle calculation unit 41 based on the signal corresponding to the light incident on the light receiving element. The control unit 4 may control the rotation of the measurement object based on the absolute rotation angle. Since the encoder 1 does not need to integrate the pulse signals output from the light receiving elements, it does not need to return the optical scale 2 to the origin when the power is turned on. This enables the encoder 1 to be quickly started when the power is turned on.
Fig. 2 is an oblique view of a module package provided in the encoder shown in fig. 1. Fig. 3 is a sectional view of a module package provided in the encoder shown in fig. 1. Fig. 4 is a plan view of a module package included in the encoder shown in fig. 1. The light receiving and projecting module package 3 includes: a light emitting element 31 that irradiates the optical scale 2 with light; a light receiving element 32 that detects light from the optical scale 2; and a package substrate 30 on which the light emitting element 31 and the light receiving element 32 are mounted.
The light emitting element 31 and the light receiving element 32 are mounted on the mounting surface 30a of the package substrate 30. The mounting surface 30a is formed in a rectangular shape. The projection/reception module package 3 is disposed so as to face the optical pattern 20 with the mounting surface 30a facing the optical scale 2.
The encoder 1 has an encoder substrate to which the package substrate 30 is connected. In fig. 2 and 3, the encoder board is not shown. In the encoder substrate, various processes are performed on the rear side of the projection/reception module package 3. The control unit 4 is disposed on the encoder board. Specifically, the encoder board includes a processing circuit that executes processing of the control unit 4. The angle calculation unit 41 and the light emission amount adjustment unit 42 are functional units included in the control unit 4.
The mounting surface 30a is provided with a terminal connected to the encoder board. The terminals are provided on all four sides of the rectangle of the mounting surface 30 a. Each terminal is an end face through hole, a back surface electrode, or the like. Since the terminals are provided on all four sides of the mounting surface 30a, the mounting accuracy of the light emitting element 31 and the light receiving element 32 is improved.
The package substrate 30 is preferably formed of the same substrate as the encoder substrate. The encoder substrate is made of, for example, a glass epoxy substrate. In this case, the package substrate 30 is also preferably made of a glass epoxy substrate.
The light emitting element 31 is an element having a light emitting surface 31a for emitting light. The light Emitting element 31 is, for example, a point light source led (light Emitting diode) that emits near infrared light. The light emitting element 31 is bonded to the package substrate 30 such that the light emitting surface 31a is parallel to the mounting surface 30 a.
The light receiving element 32 is an element having a light receiving surface 32a for receiving light. The light receiving element 32 is an imaging device such as a cmos (complementary Metal Oxide semiconductor) image sensor or a ccd (charge Coupled device) image sensor, and has a set of pixels arranged in one direction. The light-receiving element 32 is bonded to the package substrate 30 such that the light-receiving surface 32a is parallel to the mounting surface 30 a.
The light receiving element 32 outputs a signal corresponding to the intensity of light incident on the light receiving surface 32 a. Specifically, the light receiving element 32 converts light received on the light receiving surface 32a into an analog voltage signal. The light-receiving element 32 further converts the Analog voltage signal into a Digital voltage signal by an a/D (Analog-to-Digital) converter built in the light-receiving element 32. Thus, the light receiving element 32 outputs a signal corresponding to the intensity of the light incident on the light receiving surface 32 a. The light receiving element 32 outputs the generated signal to the control unit 4. In fig. 2 to 4, the a/D converter is not shown. The signal output from the light receiving element 32 is a signal corresponding to light reflected by the optical scale 2 and received by the light receiving element 32. Therefore, the signal received by the control unit 4 corresponds to the rotational position of the optical scale 2.
The light receiving and projecting module package 3 has a light transmissive resin 33 covering the mounting surface 30 a. The light-transmitting resin 33 encapsulates the light-emitting element 31 and the light-receiving element 32. The light transmissive resin 33 has a 1 st portion 33a covering a region of the mounting surface 30a where the light emitting element 31 is provided, and a 2 nd portion 33b covering a region of the mounting surface 30a where the light receiving element 32 and the bonding wire 35 are provided. The bonding wire 35 connects the light-receiving element 32 and the package substrate 30. In fig. 2, the light emitting element 31, the light receiving element 32, and the bonding wire 35, which are components covered with the light transmissive resin 33, are indicated by broken lines. In fig. 4, the light-emitting element 31, the light-receiving element 32, and the bonding wire 35, which are the components covered with the light-transmissive resin 33, are indicated by solid lines. In order to match the linear expansion coefficients of the light transmissive resin 33 and the package substrate 30, an epoxy resin, for example, is used for the light transmissive resin 33. The distance between the surface of the 2 nd portion 33b facing the optical scale 2 and the bonding wire 35 is shorter than the distance between the surface of the 2 nd portion 33b facing the optical scale 2 and the light receiving surface 32 a. Further, the bonding wire 35 is provided in a portion other than a portion between the light emitting element 31 and the light receiving element 32 in the mounting surface 30 a. Thus, the light receiving and projecting module package 3 can prevent the bonding wire 35 from interfering with light incident from the light emitting element 31 to the light receiving element 32.
The light-emitting/receiving module package 3 has a light-shielding resin 34 as a light-shielding portion. The light-shielding resin 34 absorbs or scatters incident light, thereby suppressing the transmission of the incident light. The light-shielding resin 34 is an element for suppressing stray light, which is unnecessary light transmitted through the light-emitting/receiving module package 3. The light-shielding resin 34 is provided between the 1 st portion 33a and the 2 nd portion 33 b. The light transmissive resin 33 is divided into the 1 st portion 33a and the 2 nd portion 33b by the light blocking resin 34. As the light-shielding resin 34, an epoxy resin is used in the same manner as the light-transmitting resin 33.
Some of the light emitted from the light emitting element 31 is not emitted from the projection/light receiving module package 3 but stays in the 1 st portion 33a by fresnel reflection or the like at the interface of the 1 st portion 33 a. As described above, the light stays at the 1 st portion 33a, and thus stray light is generated in the light projecting and receiving module package 3. When the stray light enters the light receiving element 32, a component corresponding to the light entering the light receiving element 32 from the optical scale 2 and a component corresponding to the stray light are mixed in the signal output from the light receiving element 32. The stray light is incident on the light receiving element 32, and it is difficult for the encoder 1 to calculate an accurate rotation angle.
The light-blocking resin 34 blocks light traveling from the 1 st portion 33a toward the 2 nd portion 33b, thereby suppressing the traveling of stray light toward the light-receiving element 32. The light-shielding resin 34 shields light that is incident from the light-emitting element 31 without being reflected at the interface of the 1 st portion 33a, or light that is multiply reflected between the package substrate 30 and the optical scale 2, in addition to light that is reflected at the interface.
The light-shielding resin 34 is formed in a plate shape. The 1 st end, which is one end of the light-shielding resin 34 in the direction perpendicular to the mounting surface 30a, is in contact with the mounting surface 30 a. The 1 st portion 33a and the 2 nd portion 33b are divided by the light-shielding resin 34 on the mounting surface 30 a. The second end 2 of the light-shielding resin 34 in the direction perpendicular to the mounting surface 30a is a position in the direction perpendicular to the mounting surface 30a, and is set to the same position as the surface on the opposite side of the 1 st portion 33a from the mounting surface 30 a. Therefore, the 2 nd end of the light-shielding resin 34 is exposed on the surface of the projection/reception module package 3 facing the optical scale 2.
The light-shielding resin 34 is disposed at a position where light traveling from the light-emitting element 31 to the light-receiving element 32 via reflection on the optical scale 2 is not shielded. The light-shielding resin 34 is disposed such that the surface of the light-shielding resin 34 on the 1 st portion 33a side and the surface of the light-shielding resin 34 on the 2 nd portion 33b side are perpendicular to the mounting surface 30 a.
It is known that a glass epoxy substrate transmits a part of light such as near infrared rays. When the package substrate 30 is a glass epoxy substrate, a part of the light emitted from the light emitting element 31 may be transmitted through the package substrate 30 and reach the light receiving element 32 directly or after being reflected in the 1 st portion 33 a. As described above, there is a possibility that stray light transmitted through the package substrate 30 may enter the light receiving element 32. In order to suppress incidence of light into the package substrate 30, a black glass epoxy substrate may be used for the package substrate 30. Alternatively, a light-shielding layer for suppressing incidence of light into the package substrate 30 or transmission of light inside the package substrate 30 may be formed on the surface of the package substrate 30. For the light shielding layer, a metal film, a black resist layer, or a combination of the metal film and the black resist layer is used. This prevents stray light from entering the light receiving element 32 in the light receiving and projecting module package 3. In addition, if the same effects as those obtained by using these materials are obtained, a method using another material can be applied in order to prevent stray light from entering the light receiving element 32.
Here, the arrangement of the components of the light-emitting and light-receiving module package 3 is defined by 3 axes perpendicular to each other, that is, an X axis, a Y axis, and a Z axis. The Z-axis direction is a direction perpendicular to the mounting surface 30a, i.e., the 1 st direction. The X-axis direction is a direction in which the 1 st portion 33a and the 2 nd portion 33b are arranged with the light-shielding resin 34 interposed therebetween. The Y-axis direction is a 2 nd direction perpendicular to the direction in which the 1 st portions 33a and the 2 nd portions 33b are arranged and perpendicular to the 1 st direction. The X-axis direction and the Y-axis direction are directions parallel to the mounting surface 30 a. The direction of the arrow indicating the Z-axis direction is the direction in which the mounting surface 30a faces.
The length L2 of the 2 nd portion 33b in the Z-axis direction is shorter than the length L1 of the 1 st portion 33a in the Z-axis direction. In other words, the thickness of the 2 nd portion 33b in the direction perpendicular to the mounting surface 30a is thinner than the thickness of the 1 st portion 33a in the direction perpendicular to the mounting surface 30 a. The effect obtained by shortening the length L2 as compared with the length L1 will be described later.
The encoder 1 detects the light reflected by the optical pattern 20 to determine the rotation angle of the optical scale 2. Instead of detecting the light reflected by the optical pattern 20, the encoder 1 may have a structure for detecting the light transmitted through the optical pattern 20.
Next, the configuration of the angle calculation unit 41 will be explained. Fig. 5 is a block diagram showing a configuration of an angle calculation unit included in the encoder shown in fig. 1. The angle calculation unit 41 includes a light amount distribution correction unit 44, an edge detection unit 45, a rough detection unit 46, a high-precision detection unit 47, and a rotation angle detection unit 48. The light receiving element 32 outputs a signal corresponding to the intensity of the light incident on the light receiving surface 32a to the light amount distribution correcting unit 44.
Fig. 6 is a diagram showing an example of a signal waveform of a signal input to the light amount distribution correcting unit included in the angle calculating unit shown in fig. 5. The vertical axis of the graph shown in fig. 6 represents the signal intensity, and the horizontal axis represents the position of the pixel. The signal 11 of level "1", which is the peak value in the signal waveform, corresponds to the reflection portion 21 in the encoded optical pattern 20. The bottom of the signal waveform, i.e., the signal 12 of level "0", corresponds to the non-reflective portion 22 in the encoded optical pattern 20.
The signal intensity of the signal 11 varies from pixel to pixel due to the light amount distribution of the light-emitting element 31, the fluctuation of the gain of each pixel included in the light-receiving element 32, and the like. The signal intensity of the signal 12 is also different for each pixel, similarly to the signal intensity of the signal 11. The light amount distribution correcting section 44 performs correction for making the signal intensities of the signals 11 uniform and correction for making the signal intensities of the signals 12 uniform. The light amount distribution correcting section 44 corrects the input signals, thereby obtaining signals in which the signal intensities of the signals 11 are uniform and the signal intensities of the signals 12 are uniform.
Fig. 7 is a diagram showing an example of a signal waveform after correction in the light amount distribution correction unit included in the angle calculation unit shown in fig. 5. The vertical axis of the graph shown in fig. 7 represents the signal intensity, and the horizontal axis represents the position of the pixel. In the corrected signal waveform 13, the signal intensity in the peak is set to be uniform, and the signal intensity in the bottom is set to be uniform. The correction method of the light amount distribution correction unit 44 may be any method as long as it can suppress fluctuations in signal intensity due to light amount distribution or the like. The light amount distribution correcting section 44 outputs the corrected signal to the edge detecting section 45.
The edge detection unit 45 calculates a pixel value, which is a value indicating a pixel having a signal intensity that matches the threshold level 14 set in advance, for each edge based on the signal corrected by the light amount distribution correction unit 44. The edge is a boundary of the reflective part 21 and the non-reflective part 22 in the optical pattern 20. The edge detection unit 45 outputs the edge pixel value, which is the calculated pixel value, to the rough detection unit 46. The edge pixel values represent the location of the edge.
The coarse detection unit 46 decodes a bit pattern projected on the light receiving element 32 among the optical patterns 20 based on the input edge pixel value. The rough detection unit 46 decodes the bit pattern, thereby calculating a rough absolute rotation angle 49.
Fig. 8 is a diagram for explaining a method of calculating a rough absolute rotation angle from the signal of the signal waveform shown in fig. 7. The bit string 15 shown in fig. 8 is a bit string corresponding to the signal of the signal waveform 13. The coarse detection unit 46 converts the signal of the signal waveform 13 into the bit string 15, which is an array of symbols "0" and "1", in accordance with the position of the edge represented by the edge pixel value.
The look-up table 16 holds the absolute rotation angle and the bit string of the optical scale 2 in association with each other. The look-up table 16 is stored in advance in a memory of the control unit 4. The illustration of the memory is omitted in fig. 1 to 5. The rough detection unit 46 reads out the absolute rotation angle corresponding to the same bit string as the bit string 15 from the look-up table 16, and thereby obtains a rough absolute rotation angle 49. The rough detection unit 46 outputs the rough absolute rotation angle 49 to the high-accuracy detection unit 47.
The high-accuracy detection unit 47 calculates the phase shift amount of the pattern projected on the light receiving element 32 with high accuracy based on the rough absolute rotation angle 49. The rough absolute rotation angle 49 obtained by the rough detection unit 46 is the absolute rotation angle in bit units of the optical scale 2. The high-accuracy detection unit 47 detects a phase shift amount indicating a deviation between the rough absolute rotation angle 49 and the high-accuracy absolute rotation angle.
Fig. 9 is a diagram for explaining a method of calculating a high-precision absolute rotation angle from a rough absolute rotation angle explained by reference to fig. 8. As shown in fig. 9, the high-accuracy detection unit 47 detects the phase shift amount 17 from the position of the reference pixel 18 to the edge pixel position 19, which is the position of the edge pixel closest to the reference pixel 18. The reference pixel 18 is a pixel that is used as a reference when calculating a high-precision absolute rotation angle, and may be any pixel. The phase shift amount 17 corresponds to a difference between the position of the reference pixel 18 and the edge pixel position 19. The high-accuracy detection unit 47 outputs the rough absolute rotation angle 49 and the phase shift amount 17 to the rotation angle detection unit 48.
The rotation angle detection unit 48 calculates a high-precision absolute rotation angle for a unit finer than the 1-bit unit of the optical scale 2 based on the phase shift amount 17. Specifically, the rotation angle detection unit 48 calculates a high-precision absolute rotation angle by adding the phase shift amount 17 calculated by the high-precision detection unit 47 to the rough absolute rotation angle 49 calculated by the rough detection unit 46. The rotation angle detection unit 48 outputs the position data 43, which is the calculation result of the absolute rotation angle with high accuracy, to an external device.
Next, an effect obtained by shortening the length L2 of the 2 nd portion 33b in comparison with the length L1 of the 1 st portion 33a in the projection/light-receiving module package 3 will be described. The bonding wire 35 is encapsulated and protected by the light transmissive resin 33. Generally, since the thermal expansion coefficients are different between the materials of the light transmissive resin 33 and the bonding wire 35, the bonding wire 35 may be subjected to stress due to expansion or contraction of the light transmissive resin 33 caused by a temperature change. When the bonding wire 35 is broken due to repeated stress, the light receiving and projecting module package 3 cannot send a signal from the light receiving element 32 to the angle calculation unit 41, and thus cannot calculate the rotation angle.
In embodiment 1, the thickness of the 2 nd portion 33b in the Z-axis direction is thinner than the thickness of the 1 st portion 33a in the Z-axis direction. Since the thickness of the 2 nd portion 33b is smaller than the thickness of the 1 st portion 33a, the amount of the light transmissive resin 33 in the 2 nd portion 33b is reduced as compared with the case where the thickness of the 2 nd portion 33b is the same as the thickness of the 1 st portion 33 a. In the 2 nd portion 33b, the amount of the light transmissive resin 33 is reduced, and thus the amount of expansion and contraction during a temperature change is reduced. As the expansion amount and the contraction amount decrease, the light transmissive resin 33 expands or contracts and the stress applied to the bonding wire 35 decreases. This reduces breakage of the bonding wire 35 in the light receiving and projecting module package 3.
When the thickness of the 1 st site 33a is reduced as in the case of the thickness of the 2 nd site 33b, light reflected from the light emitting element 31 or the wiring pattern connected to the light emitting element 31 by reflection at the interface of the light transmissive resin 33 at the 1 st site 33a increases, and thus stray light increases. The light receiving and projecting module package 3 maintains a thickness capable of suppressing stray light with the 1 st portion 33 a.
In the manufacture of the light receiving and projecting module package 3, as compared with the case where the package substrate 30 is provided with the through holes and the bonding wires 35 are inserted into the through holes, the processing of providing the same number of through holes as the number of the bonding wires 35 is not required. Therefore, the light receiving and projecting module package 3 can avoid the problem that the processing at the time of manufacturing becomes complicated. Further, since the through hole is not necessary, the problem of increasing the size of the projection/light-receiving module package 3 can be avoided.
The light transmitting resin 33 is formed in the light receiving module package 3 such that the thickness of the 2 nd portion 33b is smaller than the thickness of the 1 st portion 33a, whereby the breakage of the bonding wire 35 can be reduced. The light receiving and projecting module package 3 can easily have a structure in which the thickness of the light transmissive resin 33 is different only at the 1 st portion 33a and the 2 nd portion 33b, and the breakage of the bonding wire 35 can be reduced. As described above, the encoder 1 has an effect of reducing breakage of the bonding wire 35 by a structure which is small and can be easily processed.
Fig. 10 is a sectional view of a module package included in an encoder according to embodiment 2 of the present invention. Fig. 11 is a plan view of a module package included in the encoder shown in fig. 10. In embodiment 2, the length L2 in the Z-axis direction is shorter than the length L1 of the 1 st portion 33a in the Z-axis direction in a part of the 2 nd portion 33 b. In embodiment 2, the same components as those in embodiment 1 are denoted by the same reference numerals, and the description will be mainly given of a configuration different from that in embodiment 1. In fig. 11, the light emitting element 31, the light receiving element 32, and the bonding wire 35, which are the components covered with the light transmissive resin 33, are indicated by solid lines.
The portion 33c of the 2 nd portion 33b having the length L2 is a portion other than the portion 33d on which the light receiving surface 32a is provided, and is a portion other than the portion 33e on the 1 st portion 33a side of the light receiving surface 32 a. In the portion 33d and the portion 33e, the length in the Z-axis direction is a length L1. A concave curved surface 36 is formed between the portion 33c and the portion 33 d. That is, an inclined portion is disposed between the portion 33c and the portion 33 d. The face between the portion 33c and the portion 33d may be a slope having an inclination with respect to the mounting face 30 a. By providing the inclined portion between the portion 33c and the portion 33d, light emitted from the light emitting element 31 and incident on the inclined portion is not incident on the light receiving element 32. Therefore, the light receiving and projecting module package 3 can suppress stray light.
Of the light incident on the light receiving surface 32a, the light reflected by the light receiving surface 32a and the light reflected around the light receiving surface 32a may be reflected by fresnel at the interface of the 2 nd portion 33b to become stray light toward the light receiving surface 32 a. As the portion 33d provided with the light receiving surface 32a becomes thinner, the amount of light reflected at the interface of the 2 nd portion 33b increases, and thus stray light increases. In embodiment 2, the thickness of the portion 33d in the Z-axis direction is the same as the thickness of the 1 st portion 33a, and thus the light receiving and projecting module package 3 can suppress stray light toward the light receiving surface 32 a.
According to embodiment 2, the thickness of the portion 33c, which is a part of the 2 nd portion 33b, is thinner than the thickness of the 1 st portion 33 a. The amount of the light transmissive resin 33 in the 2 nd portion 33b of the light receiving and projecting module package 3 is reduced, whereby the breakage of the bonding wire 35 can be prevented. In the projection/light-receiving module package 3, the thickness of the portion 33d where the light-receiving surface 32a is provided is not reduced, and thus stray light toward the light-receiving surface 32a can be suppressed. Thereby, the encoder 1 can calculate an accurate rotation angle.
Fig. 12 is a perspective view of a module package included in an encoder according to embodiment 3 of the present invention. Fig. 13 is a plan view of a module package included in the encoder shown in fig. 12. In embodiment 3, the length L4 in the Y axis direction is shorter than the length L3 of the 1 st portion 33a in the Y axis direction in a part of the 2 nd portion 33 b. In embodiment 3, the same components as those in embodiments 1 and 2 are denoted by the same reference numerals, and configurations different from those in embodiments 1 and 2 will be mainly described. In fig. 12 and 13, the package substrate 30 is not shown. In fig. 13, the light-emitting element 31, the light-receiving element 32, and the bonding wire 35, which are the components covered with the light-transmissive resin 33, are indicated by solid lines.
Since the length L4 of a part of the 2 nd portion 33b is shorter than the length L3 of the 1 st portion 33a, the amount of the light-transmissive resin 33 in the 2 nd portion 33b is smaller than that in the case where the entire length of the 2 nd portion 33b is the same length L3 as the 1 st portion 33 a. The light projecting and receiving module package 3 can reduce the stress applied to the bonding wire 35 in the Y-axis direction. This reduces breakage of the bonding wire 35 in the light receiving and projecting module package 3.
In embodiment 3, the length of the 2 nd portion 33b in the Y axis direction may be a length L4. In this case, the light receiving and projecting module package 3 can also reduce breakage of the bonding wire 35. The light receiving and projecting module package 3 can easily have a structure in which the length of the light transmissive resin 33 is different only at least in a part of the 1 st portion 33a and the 2 nd portion 33b, and the breakage of the bonding wire 35 can be reduced. Thus, the encoder 1 has an effect of reducing breakage of the bonding wire 35 by a small-sized and easily-machinable structure, as in the case of embodiment 1.
The configuration described in the above embodiment is an example of the content of the present invention, and may be combined with other known techniques, and a part of the configuration may be omitted or modified without departing from the scope of the present invention.
Description of the reference numerals
1 encoder, 2 optical scale, 3 projection/reception optical module package, 4 control unit, 5 rotation axis, 11, 12 signal, 13 signal waveform, 14 threshold level, 15 bit string, 16 lookup table, 17 phase shift amount, 18 reference pixel, 19 edge pixel position, 20 optical pattern, 21 reflection unit, 22 non-reflection unit, 30 package substrate, 30a mounting surface, 31 light emitting element, 31a light emitting surface, 32 light receiving element, 32a light receiving surface, 33 light transmissive resin, 33a 1 st part, 33b 2 nd part, 33c, 33d, 33e part, 34 light shielding resin, 35 bonding wire, 36 curved surface, 41 angle calculation unit, 42 light emission amount adjustment unit, 43 position data, 44 light amount distribution correction unit, 45 edge detection unit, 46 coarse detection unit, 47 high precision detection unit, 48 rotation angle detection unit, 49 coarse absolute rotation angle, L1, L2, L3, L4 length.
Claims (5)
1. An encoder, characterized by having:
a scale having an optical pattern; and
a module package having a substrate on which a light emitting element for irradiating light to the scale and a light receiving element having a light receiving surface on which light from the scale is incident are mounted, and an optically transparent resin covering a mounting surface on which the light emitting element and the light receiving element are mounted in the substrate,
the light-transmissive resin has a 1 st portion covering a region of the mounting surface where the light-emitting element is provided, and a 2 nd portion covering a region of the mounting surface where the light-receiving element and a bonding wire connecting the light-receiving element and the substrate are provided,
the thickness of the light-transmissive resin in the direction perpendicular to the mounting surface is smaller at least in part at the 2 nd portion than at the 1 st portion, or the length of the light-transmissive resin in the direction parallel to the mounting surface and perpendicular to the direction in which the light-emitting elements and the light-receiving elements are arranged is shorter at least in part at the 2 nd portion than at the 1 st portion.
2. The encoder according to claim 1,
the portion of the 2 nd portion, which is thinner than the 1 st portion in thickness, is a portion other than a portion where the light receiving surface is provided, and is a portion other than a portion on the 1 st portion side of the light receiving surface.
3. The encoder according to claim 1 or 2,
an inclined portion is provided between the 1 st portion and a portion of the 2 nd portion having a thickness smaller than that of the 1 st portion.
4. The encoder according to any of the claims 1 to 3,
a light shielding portion is provided between the 1 st portion and the 2 nd portion.
5. The encoder according to claim 4,
the substrate is a substrate composed of glass epoxy resin,
the light transmissive resin and the light shielding portion are epoxy resins.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/JP2019/015769 WO2020208773A1 (en) | 2019-04-11 | 2019-04-11 | Encoder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113661376A true CN113661376A (en) | 2021-11-16 |
Family
ID=69320905
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201980094996.8A Pending CN113661376A (en) | 2019-04-11 | 2019-04-11 | Encoder for encoding a video signal |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP6639750B1 (en) |
| KR (1) | KR102360458B1 (en) |
| CN (1) | CN113661376A (en) |
| TW (1) | TWI718040B (en) |
| WO (1) | WO2020208773A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPWO2021192148A1 (en) * | 2020-03-26 | 2021-09-30 | ||
| KR20230043363A (en) | 2021-09-24 | 2023-03-31 | 삼성전자주식회사 | Semiconductor device |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080251703A1 (en) * | 2006-09-11 | 2008-10-16 | Olympus Corporation | Optical encoder |
| CN101315911A (en) * | 2007-05-30 | 2008-12-03 | 恩益禧电子股份有限公司 | Semiconductor device |
| US20100165359A1 (en) * | 2007-04-10 | 2010-07-01 | Olympus Corporation | Optical encoder |
| JP2010223629A (en) * | 2009-03-19 | 2010-10-07 | Olympus Corp | Optical encoder |
| JP2012094612A (en) * | 2010-10-26 | 2012-05-17 | Nichia Chem Ind Ltd | Light-emitting device |
| JP2017092352A (en) * | 2015-11-13 | 2017-05-25 | ローム株式会社 | Light-receiving/emitting device and manufacturing method of light-receiving/emitting device |
| WO2018163424A1 (en) * | 2017-03-10 | 2018-09-13 | 三菱電機株式会社 | Absolute encoder |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4101700B2 (en) * | 2002-06-03 | 2008-06-18 | 三菱電機株式会社 | Photoelectric rotary encoder |
| JP2010223630A (en) * | 2009-03-19 | 2010-10-07 | Olympus Corp | Optical encoder |
| JP2010223636A (en) * | 2009-03-19 | 2010-10-07 | Olympus Corp | Optical encoder |
| JP2010243323A (en) * | 2009-04-06 | 2010-10-28 | Olympus Corp | Optical encoder |
| TWI447357B (en) * | 2009-11-20 | 2014-08-01 | Everlight Electronics Co Ltd | Reflective type optical encoder |
| WO2012042568A1 (en) * | 2010-09-29 | 2012-04-05 | 三菱電機株式会社 | Method of producing resin component, and optical encoder comprising the resin component |
| US8847144B2 (en) * | 2011-08-08 | 2014-09-30 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Enhanced optical reflective encoder |
| KR101361844B1 (en) * | 2012-12-04 | 2014-02-12 | (주)파트론 | Proximity ambient light sensor package and mobile apparatus with it |
| JP2018077145A (en) * | 2016-11-10 | 2018-05-17 | スタンレー電気株式会社 | Rotation detector and rotational body used in the same |
| JP6407502B1 (en) * | 2018-02-20 | 2018-10-17 | 三菱電機株式会社 | Absolute encoder |
-
2019
- 2019-04-11 KR KR1020217031535A patent/KR102360458B1/en active IP Right Grant
- 2019-04-11 JP JP2019537395A patent/JP6639750B1/en active Active
- 2019-04-11 WO PCT/JP2019/015769 patent/WO2020208773A1/en active Application Filing
- 2019-04-11 CN CN201980094996.8A patent/CN113661376A/en active Pending
-
2020
- 2020-03-31 TW TW109110950A patent/TWI718040B/en active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080251703A1 (en) * | 2006-09-11 | 2008-10-16 | Olympus Corporation | Optical encoder |
| US20100165359A1 (en) * | 2007-04-10 | 2010-07-01 | Olympus Corporation | Optical encoder |
| CN101315911A (en) * | 2007-05-30 | 2008-12-03 | 恩益禧电子股份有限公司 | Semiconductor device |
| JP2010223629A (en) * | 2009-03-19 | 2010-10-07 | Olympus Corp | Optical encoder |
| JP2012094612A (en) * | 2010-10-26 | 2012-05-17 | Nichia Chem Ind Ltd | Light-emitting device |
| JP2017092352A (en) * | 2015-11-13 | 2017-05-25 | ローム株式会社 | Light-receiving/emitting device and manufacturing method of light-receiving/emitting device |
| WO2018163424A1 (en) * | 2017-03-10 | 2018-09-13 | 三菱電機株式会社 | Absolute encoder |
Also Published As
| Publication number | Publication date |
|---|---|
| TW202041834A (en) | 2020-11-16 |
| JP6639750B1 (en) | 2020-02-05 |
| KR20210126133A (en) | 2021-10-19 |
| WO2020208773A1 (en) | 2020-10-15 |
| JPWO2020208773A1 (en) | 2021-05-06 |
| TWI718040B (en) | 2021-02-01 |
| KR102360458B1 (en) | 2022-02-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7309855B2 (en) | Reflective encoder with light shield and electronic device using such reflective encoder | |
| CN110392820B (en) | Absolute encoder | |
| US7622698B2 (en) | Detection head | |
| US7304294B2 (en) | Reflective encoder with reduced background noise | |
| US8847144B2 (en) | Enhanced optical reflective encoder | |
| CN113661376A (en) | Encoder for encoding a video signal | |
| US7784694B2 (en) | Reflective encoder with lens on code strip | |
| JP2005156549A (en) | Optical encoder | |
| GB2349948A (en) | Optical displacement detecting apparatus | |
| JP2024012600A (en) | Optical module and reflection encoder | |
| JP4466083B2 (en) | Ranging light source and ranging device | |
| JP4999596B2 (en) | Reflective photo sensor | |
| WO2021192148A1 (en) | Rotation angle detection device | |
| US20230296412A1 (en) | Method for producing an optical position encoder | |
| JP2010002324A (en) | Optical encoder | |
| JP5278276B2 (en) | Ranging light source and ranging device using the same | |
| US20230332943A1 (en) | Optical sensor device | |
| JP2005300306A (en) | Optical displacement measurement apparatus | |
| CN117859042A (en) | Encoder with a plurality of sensors | |
| JPH04231808A (en) | Angle-of-inclination detector | |
| JP5253138B2 (en) | Optical encoder | |
| US20180113007A1 (en) | Reflective absolute encoder sensor | |
| WO2007132602A1 (en) | Optical encoder and motor with encoder |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |