Light source structure for encoder chip testing

Abstract

The application provides a light source structure for encoder chip testing, comprising a light source body, wherein the light source body comprises: a PCB board for mounting a light source chip for emitting test light, the light source chip being electrically connected with the PCB board; an optical lens for changing the direction of light emitted by the light source chip, the optical lens being arranged on the projection direction of light emitted by the light source chip; and a can body support for supporting the optical lens and allowing the light emitted by the light source chip to pass through and project to the optical lens, the can body support being fixed on the PCB board and covering the light source chip, and the optical lens being fixed on the can body support. The light source structure for encoder chip testing provided by the application integrates a light homogenizing or shape modulating device in a light source package according to different encoder chip testing requirements, avoids the use of additional elements for forming a special distribution, and improves the accuracy of test results and test efficiency.

Description

Technical Field

[0001] This invention relates to the field of photoelectric detection technology, and in particular to a light source structure for testing encoder chips. Background Technology

[0002] In encoder chip testing, various types of light sources are often needed to illuminate the chip's photosensitive area to generate photoelectric signals, facilitating the analysis of the chip's output signals. However, since the photosensitive arrays on the encoder chip surface often have different distributions and usage requirements, conventional lighting structures cannot meet the testing needs of the photosensitive arrays. It is necessary to specifically combine light-diffusing elements or code disks, etc., according to the testing requirements of different encoder chips, in addition to the light source itself, to form a special distribution to achieve the desired testing effect. The matching and adjustment of optical components are cumbersome, and the effect of forming a special distribution is not ideal, affecting the accuracy and efficiency of the test results.

[0003] Therefore, it is necessary to provide a light source structure for encoder chip testing to effectively solve the above problems. Summary of the Invention

[0004] This invention provides a light source structure for encoder chip testing. According to different encoder chip testing requirements, a uniform light or shape modulation device is integrated into the light source package, avoiding the need for additional components with special distributions, thereby improving the accuracy and efficiency of test results.

[0005] This invention provides a light source structure for encoder chip testing, including a light source body, the light source body comprising:

[0006] A PCB board for mounting a light source chip that emits test light, the light source chip being electrically connected to the PCB board;

[0007] An optical lens, used to change the direction of light emitted by the light source chip, is disposed in the projection direction of the light emitted by the light source chip;

[0008] A can body support is provided to support the optical lens and allow light emitted by the light source chip to pass through it and be projected onto the optical lens;

[0009] The tank support is fixed to the PCB board and covers the light source chip, and the optical lens is fixed to the tank support.

[0010] Preferably, the tank support is a hollow columnar structure, one end of the tank support is soldered to the PCB board, the light source chip is located on the central axis of the tank support, and the optical lens is fixed to the other end of the tank support; the light source chip is an LED light source chip or a VCSEL light source chip, and the light source chip adopts an on-board chip packaging form.

[0011] Preferably, the light source body is a uniform light source, the light source chip is a point light source chip, the light source chip is fixed on the PCB board, the light-emitting surface of the light source chip faces the optical lens, the optical lens includes a first lens, the first lens has a central plane, the surface of the first lens near the light source chip is a quadratic surface, the surface of the first lens away from the light source chip is an aspherical surface, the quadratic surface and the aspherical surface are located on opposite sides of the central plane, and the light emitted by the light source chip is collimated and uniformly projected onto the projection surface after being refracted by the first lens.

[0012] Preferably, the vector height of a point on the quadratic surface from the intermediate plane is calculated using the following formula:

[0013]

[0014] Among them, Z M R is the vector height of a point on the quadric surface from the intermediate plane; P is the radius of curvature of the quadric surface; P is the quadric surface coefficient, which is an adjustable setting parameter; y is the distance of a point on the quadric surface from the central axis of the quadric surface.

[0015] The vector height of a point on the aspherical surface from the intermediate plane is calculated using the following formula:

[0016]

[0017] Among them, Z N is the vector height of a point on the aspherical surface from the intermediate plane; r is the distance of a point on the aspherical surface from the central axis of the aspherical surface; k is the quadratic surface coefficient, which is an adjustable setting parameter; c is the surface curvature of the aspherical surface; A i Z represents the coefficients of the corresponding order. i (ρ,ψ) represents the elevation components of a point on an aspherical surface at the meridional angle ρ and the sagittal angle ψ.

[0018] Preferably, the light source body is an array light spot projection light source, and there are multiple light source chips. The multiple light source chips are arranged in an array and fixed on the PCB board, and the light-emitting surfaces of the multiple light source chips are all facing the optical lens. The optical lens includes a second lens and a third lens arranged in sequence, and an aperture is provided between the second lens and the third lens. The optical lens projects the array light spot emitted by the light source chip onto a projection surface at a set distance from the light source body.

[0019] Preferably, both the second lens and the third lens are plano-convex lenses, the convex surface of the second lens is the side closer to the light source chip, the plane of the second lens is opposite to the plane of the third lens, and the convex surface of the third lens is the side away from the light source chip.

[0020] Preferably, the aperture has a light-limiting hole that allows light to pass through, and there is at least one light-limiting hole with a diameter of 1mm-2mm.

[0021] Preferably, the light source body is a short-axis uniform light source, the light source chip is a point light source chip, the light source chip is disposed in the middle of the tank support and electrically connected to the PCB board, the light-emitting surface of the light source chip faces the PCB board, the surface of the PCB board near the light source chip is coated with a metal reflective film, the optical lens includes a fourth lens, and the light emitted by the light source chip is collimated and uniformly projected onto the projection surface after being reflected by the metal reflective film and refracted by the fourth lens in sequence.

[0022] Preferably, the can body support is filled with optical encapsulation adhesive, the fourth lens is a plano-convex lens, the convex surface of the fourth lens is the side away from the light source chip, and the focal length of the fourth lens is calculated using the following formula:

[0023] f = n*(d1 + d2)

[0024] Where f is the focal length of the optical lens, n is the refractive index of the optical encapsulation adhesive, d1 is the distance from the light source chip to the PCB board, and d2 is the distance from the PCB board to the optical lens.

[0025] Preferably, the PCB board has a groove on the side near the light source chip, and the surface of the groove is coated with a metal reflective film to form a concave reflector. The focal length of the fourth lens is calculated using the following formula:

[0026]

[0027] Where f is the focal length of the optical lens, n is the refractive index of the optical encapsulation adhesive, R1 is the radius of curvature of the groove, and d2 is the distance from the PCB board to the optical lens.

[0028] Preferably, the PCB board has pins reserved for supplying power to the light source chip, and the pins are electrically connected to the light source chip.

[0029] Compared with the prior art, the technical solution of the embodiments of the present invention has the following beneficial effects:

[0030] The present invention provides a light source structure for encoder chip testing. Through the packaging structure, a uniform light or shape modulation device is integrated into the light source package, which facilitates the optical testing of encoder chips, avoids the cumbersome operation of separately matching specially distributed components, and improves the accuracy and efficiency of test results.

[0031] Furthermore, by combining different light source chips with optical components, three types of light sources are formed: uniform light source, array spot projection light source, and short-axis uniform light source. These meet the testing requirements of different types of encoder chips and have a wide range of applications. Moreover, they are small in size and suitable for the narrow spaces where encoder chips are used. In particular, the short-axis uniform light source reduces the axial dimension and is especially suitable for use in narrow spaces. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention, but not all embodiments. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 A schematic diagram of a light source structure for testing an encoder chip provided in one embodiment of the present invention;

[0034] Figure 2 A schematic diagram of the optical path of a uniform light source provided in one embodiment of the present invention;

[0035] Figure 3 A schematic diagram of the optical path of an array spot projection light source provided in one embodiment of the present invention;

[0036] Figure 4 a is an array layout diagram of the light source chip of an array spot projection light source provided in an embodiment of the present invention;

[0037] Figure 4 b is an array layout diagram of the light source chip of the array spot projection light source provided in another embodiment of the present invention;

[0038] Figure 4 c is an array layout diagram of the light source chip of the array spot projection light source provided in another embodiment of the present invention;

[0039] Figure 5 A schematic diagram of the optical path of a short-axis uniform light source provided in an embodiment of the present invention.

[0040] In the picture:

[0041] 1. PCB board; 2. Light source chip; 3. Tank support; 4. Optical lens; 5. Aperture;

[0042] 41. First lens; 42. Second lens; 43. Third lens; 44. Fourth lens; 411. Quadratic surface; 412. Aspherical surface. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0045] It should be noted that the axial, radial, and circumferential directions in the embodiments of the present invention refer to the axial, radial, and circumferential directions of the tank support 3.

[0046] Based on the problems existing in the prior art, this invention provides a light source structure for encoder chip testing. According to different encoder chip testing requirements, uniform light or shape modulation devices are integrated into the light source package, avoiding the need for additional specially distributed components, thereby improving the accuracy and efficiency of test results.

[0047] Figure 1 A schematic diagram of a light source structure for testing an encoder chip provided in one embodiment of the present invention; Figure 2 A schematic diagram of the optical path of a uniform light source provided in one embodiment of the present invention; Figure 3 A schematic diagram of the optical path of an array spot projection light source provided in one embodiment of the present invention; Figure 4 a is an array layout diagram of the light source chip of an array spot projection light source provided in an embodiment of the present invention; Figure 4 b is an array layout diagram of the light source chip of the array spot projection light source provided in another embodiment of the present invention; Figure 4 c is an array layout diagram of the light source chip of the array spot projection light source provided in another embodiment of the present invention; Figure 5 This is a schematic diagram of the optical path of a uniform light source provided in one embodiment of the present invention.

[0048] Now see Figures 1 to 5This invention provides a light source structure for testing encoder chips, including a light source body, which comprises:

[0049] PCB (Printed Circuit Board) 1 is used to mount the light source chip 2 that emits test light. The light source chip 2 is electrically connected to PCB 1.

[0050] Optical lens 4 is used to change the direction of the light emitted by the light source chip 2, and it is set in the projection direction of the light emitted by the light source chip 2;

[0051] The tank support 3 is used to support the optical lens 4 and allow the light emitted by the light source chip 2 to pass through it and be projected onto the optical lens 4;

[0052] The tank support 3 is fixed on the PCB board 1 and covers the light source chip 2, and the optical lens 4 is fixed on the tank support 3.

[0053] In some embodiments, the tank support 3 is a hollow columnar structure, one end of the tank support 3 is soldered to the PCB board 1, the light source chip 2 is located on the central axis of the tank support 3, and the optical lens 4 is fixed to the other end of the tank support 3; the light source chip 2 is an LED (Light Emitting Diode) light source chip or a VCSEL (Vertical-Cavity Surface-Emitting Laser) light source chip, and the light source chip adopts the on-board chip packaging form.

[0054] The Chip On Board (COB) process begins by covering the silicon wafer placement points on the substrate surface with thermally conductive epoxy resin (usually silver-doped epoxy resin). The silicon wafer is then placed directly on the substrate surface and heat-treated until it is firmly fixed to the substrate. Finally, an electrical connection is established between the silicon wafer and the substrate using wire bonding.

[0055] See Figure 2 In some embodiments, the light source body is a uniform light source, the light source chip 2 is a point light source chip, the light source chip 2 is fixed on the PCB board 1, the light-emitting surface of the light source chip 2 faces the optical lens 4, the optical lens 4 includes a first lens 41, the first lens 41 has a middle plane, the surface of the first lens 41 near the light source chip 2 is a quadratic surface 411, the surface of the first lens away from the light source chip 2 is an aspherical surface 412, the quadratic surface 411 and the aspherical surface 412 are located on both sides of the middle plane, the light emitted by the light source chip 2 is collimated and uniformly projected onto the projection surface after being refracted by the first lens 41.

[0056] Ray collimation requires the divergence angle of the light source to be controlled within ±3°; ray uniformity requires uniform light intensity I, i.e., Imin / Imax > 0.95, ultimately forming a light spot with a diameter of not less than 3.5mm and uniform light intensity I at a distance of 0.1mm from the vertex of the light source. The axial length of the uniform light source ranges from 6mm to 10mm.

[0057] In practical implementation, the vector height of a point on the quadratic surface 411 from the intermediate plane is calculated using the following formula:

[0058]

[0059] Among them, Z M R is the vector height of a point on the quadric surface 411 from the intermediate plane; P is the radius of curvature of the quadric surface 411; P is the quadric surface coefficient, which is an adjustable setting parameter; y is the distance of a point on the quadric surface 411 from the central axis of the quadric surface.

[0060] The vector height of a point on the aspherical surface 412 from the mid-plane is calculated using the following formula:

[0061]

[0062] Among them, Z N is the vector height of a point on aspherical surface 412 from the intermediate plane; r is the distance of a point on aspherical surface 412 from the central axis of aspherical surface 412; k is the aspherical coefficient, which is an adjustable setting parameter; c is the surface curvature of the aspherical surface; A i Z represents the coefficients of the corresponding order. i (ρ,ψ) represents the elevation components of a point on the aspherical surface 412 at the meridional angle ρ and the sagittal angle ψ.

[0063] The first lens can be mass-produced quickly through molding, which is simple and convenient for mass production.

[0064] See Figure 3 and Figure 4 In some embodiments, the light source body is an array light spot projection light source, and there are multiple light source chips 2. The multiple light source chips 2 are fixed on the PCB board 1 in an array. The center of the multiple light source chips 2 in the array is located on the central axis of the tank support. The light-emitting surface of the light source chip 2 is directly facing the optical lens 4. The optical lens 4 includes a second lens 42 and a third lens 43 arranged in sequence. An aperture 5 is provided between the second lens 42 and the third lens 43. The optical lens 4 projects the array light spot emitted by the light source chip 2 onto the projection surface at a set distance from the light source body.

[0065] See Figure 4In some embodiments, the multiple light source chips 2 can be arranged in an array, in a row, in a fan shape, in a rectangle, or in other arrangements as needed, without limitation.

[0066] In some embodiments, the second lens 42 and the third lens 43 are both plano-convex lenses. The convex surface of the second lens 42 is the side closer to the light source chip 2, the plane of the second lens 42 is opposite to the plane of the third lens 43, and the convex surface of the third lens 43 is the side away from the light source chip 2.

[0067] In some embodiments, the aperture 5 has a light-limiting aperture that allows light to pass through. There is at least one light-limiting aperture, and the diameter of the light-limiting aperture is 1mm-2mm. The layout of the light-limiting aperture matches the array arrangement of multiple LED light sources 21 of the light source chip 2.

[0068] In some embodiments, the axial length of the array spot projection light source ranges from 10mm to 15mm, and the imaging distance is 15mm to 53mm from the light source body.

[0069] See Figure 5 In some embodiments, the light source body is a short-axis uniform light source, the light source chip 2 is a point light source chip, the light source chip 2 is disposed in the middle of the tank support 1 and electrically connected to the PCB board 1, the light-emitting surface of the light source chip 2 faces the PCB board 1, the surface of the PCB board 1 near the light source chip 2 is coated with a metal reflective film, the optical lens 4 includes a fourth lens 44, the light emitted by the light source chip 2 is collimated and uniformly projected onto the projection surface after being reflected by the metal reflective film and refracted by the fourth lens 44 in sequence.

[0070] Light collimation requires the divergence angle of the light source to be controlled within ±3°; light uniformity requires uniform light intensity I, i.e., Imin / Imax > 0.95. The axial length of the short-axis uniform light source is 4mm-8mm, which further shortens the axial length of the light source body compared to the uniform light source, making it more suitable for the narrow space of encoder chip applications.

[0071] In some embodiments, the can holder 3 is filled with optical encapsulation adhesive, the fourth lens 44 is a plano-convex lens, the convex surface of the fourth lens 44 is the side away from the light source chip 2, and the focal length of the fourth lens 44 is calculated by the following formula:

[0072] f = n*(d1 + d2)

[0073] Where f is the focal length of the fourth lens 44, n is the refractive index of the optical encapsulation adhesive, d1 is the distance from the light source chip 2 to the PCB board 1, and d2 is the distance from the PCB board 1 to the fourth lens 44.

[0074] In some embodiments, a groove is provided on the side of the PCB board 1 near the light source chip 2, and a metal reflective film is deposited on the surface of the groove to form a concave reflective mirror. The focal length of the fourth lens 44 is calculated using the following formula:

[0075]

[0076] Where f is the focal length of the fourth lens 44, n is the refractive index of the optical encapsulation adhesive, R1 is the radius of curvature of the groove, and d2 is the distance from the PCB board to the fourth lens 44.

[0077] In practice, the PCB board 1 has reserved pins for powering the light source chip 2, and the pins are electrically connected to the light source chip 2.

[0078] In practice, the metal reflective film is a silver film.

[0079] In practice, a metallic reflective film is deposited on the remaining portion of the PCB board 1 that is not in contact with the pins, and then the can body bracket 3 is soldered onto the PCB board 1. A certain amount of glue is then poured into the can body bracket 3, the light source chip 2 is placed with its emitting surface facing the PCB board 1, and the fourth lens 44, connected to the pre-reserved pins, is placed on top of the can body bracket 3 to complete the encapsulation.

[0080] In summary, the encoder chip testing light source structure provided by the embodiments of the present invention integrates a uniform light or shape modulation device into the light source package through a packaging structure, which facilitates the optical testing of the encoder chip, avoids the cumbersome operation of separately matching specially distributed components, and improves the accuracy and efficiency of the test results.

[0081] Furthermore, by combining different light source chips 2 with optical components, three types of light sources are formed: uniform light source, array spot projection light source, and short-axis uniform light source, which can meet the testing of different types of encoder chips and have a wide range of applications; and they are small in size, suitable for the narrow space where encoder chips are used, especially the short-axis uniform light source, which reduces the axial dimension and is particularly suitable for use in narrow space occasions.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light source structure for testing encoder chips, characterized in that, Includes a light source body, the light source body comprising: A PCB board for mounting a light source chip that emits test light, the light source chip being electrically connected to the PCB board; An optical lens, used to change the direction of light emitted by the light source chip, is disposed in the projection direction of the light emitted by the light source chip; A can body support is provided to support the optical lens and allow light emitted by the light source chip to pass through it and be projected onto the optical lens; The tank support is fixed to the PCB board and covers the light source chip; the optical lens is fixed to the tank support; the tank support is a hollow columnar structure, one end of the tank support is soldered to the PCB board, the light source chip is located on the central axis of the tank support, and the optical lens is fixed to the other end of the tank support; the light source chip is an LED light source chip or a VCSEL light source chip, and the light source chip adopts an on-board chip packaging form; The light source body is a uniform light source, the light source chip is a point light source chip, the light source chip is fixed on the PCB board, the light-emitting surface of the light source chip faces the optical lens, the optical lens includes a first lens, the first lens has a central plane, the surface of the first lens near the light source chip is a quadratic surface, the surface of the first lens away from the light source chip is an aspherical surface, the quadratic surface and the aspherical surface are located on both sides of the central plane, the light emitted by the light source chip is collimated and uniformly projected onto the projection surface after being refracted by the first lens; The vector height of a point on the quadric surface from the intermediate plane is calculated using the following formula: in, R is the vector height of a point on the quadric surface from the intermediate plane; P is the radius of curvature of the quadric surface; P is the quadric surface coefficient, which is an adjustable setting parameter; y is the distance of a point on the quadric surface from the central axis of the quadric surface. The vector height of a point on the aspherical surface from the intermediate plane is calculated using the following formula: in, is the vector height of a point on the aspherical surface from the intermediate plane; r is the distance of a point on the aspherical surface from the central axis of the aspherical surface; k is the quadratic surface coefficient, which is an adjustable setting parameter; and c is the surface curvature of the aspherical surface. For the coefficients of the corresponding order, For a point on an aspherical surface at a meridian angle and sagittal angle The sag component.

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