CN118816747A - Optical device, optical detection method and optical device design method - Google Patents

Abstract

An optical device, an optical detection method, and an optical device design method, wherein the optical detection method is suitable for use in an optical device. The optical device includes a projection unit that defines a projection range, an imaging unit that defines an imaging range, and a processing unit electrically connected to the projection unit and the imaging unit, wherein the imaging range and the projection range each define a major axis and a minor axis whose length is less than the major axis. The projection unit projects a light beam toward the object to be measured along an incident path, and after being reflected by the object to be measured, the light beam enters the imaging unit along a reflection path, and the projection of the incident path or the reflection path on the plane to be measured is parallel to the extension direction of the minor axis of the projection range or the imaging range. In this way, it is possible to avoid the occurrence of locally overexposed light spots within the effective imaging range, thereby reducing the invalid observation area to improve the measurement performance.

Description

Optical device, optical detection method and optical device design method

Technical Field

The present invention relates to an optical device and a detection method, and in particular to an optical device, an optical detection method and an optical device design method.

Background Art

In recent years, the application scope of non-contact optical detection has become more and more extensive, especially the three-dimensional detection device based on the triangulation method. However, when the surface of the object to be tested is a mirror, within the range of the lens's light collection angle, part of the signal light is reflected by the surface of the object to be tested according to the law of reflection, so that the energy is concentrated into the optical system, causing the camera to be partially overexposed. Therefore, bright spots with obvious grayscale saturation can be seen on the image, which in turn affects the detection function. In addition, there is also a demand in the industry for three-dimensional detection devices to measure the object to be tested through a glass partition. Since the surface of the glass partition is flat, part of the light beam will enter the three-dimensional detection device according to the law of reflection, resulting in the aforementioned local overexposure phenomenon (see Figure 1).

Referring to FIG. 2 and FIG. 4 , an existing three-dimensional detection instrument 1 mainly includes a projection device 11 for projecting structured light, and an imaging device 12 for receiving structured light reflected from a test piece 13 and having a light receiving half angle of γ1. The angle between the optical axis of the imaging device 12 and the optical axis of the projection device 11 is α1, and the projection of the reflection path of the light beam reflected from the test piece 13 on the test plane is perpendicular to the extension direction of the short axis of the imaging range 15. The short axis of the imaging range 15 is defined as the shorter connecting line in the length of the connecting line between the centers of two opposite sides of the quadrilateral. Among them, the light path drawn in FIG. 2 is a light path according to the law of reflection (the incident angle θi is equal to the reflection angle θr), so a light spot with local overexposure will be generated when entering the imaging device 12 through the light path. According to FIG. 2 , the projection range 14 of the projection device 11 is a quadrilateral, and the imaging range 15 of the imaging device 12 is a quadrilateral, and a schematic diagram of FIG. 4 is drawn, wherein an effective imaging range 16 is defined as a range extending outward from the projection center of the projection device 11 on the plane to D1, β1 is the angle from the projection device 11 to the boundary of the effective imaging range 16, and D1 is the distance from the local overexposure point to the projection center of the projection device 11 on the plane. In FIG. 4 , since the position of the local overexposure point is within the boundary of the test piece 13, it will affect the detection result.

Referring to FIG. 3 and FIG. 5 , generally speaking, in order to improve the Z-axis resolution and expand the effective imaging range 16 to at least include the size of the test object 13 (half of its side length is D2), the user generally increases the angle α2 between the projection device 11 and the imaging device 12 to increase β2, thereby expanding the effective imaging range 16 and solving the problem of partial overexposure. However, this method not only increases the volume of the three-dimensional detection instrument 1, but also requires a smaller aperture (i.e., reduces γ1) to provide sufficient depth of field, which easily leads to insufficient brightness during detection.

Summary of the invention

One of the objectives of the present invention is to provide an optical device for improving detection efficiency.

In some embodiments, the optical device of the present invention is suitable for measuring an object to be measured, and includes a projection unit, an imaging unit, and a processing unit.

The projection unit is used for projecting a light beam to the object to be measured and defining a projection range.

The imaging unit is used to receive the light beam reflected from the object to be measured and define an imaging range. The imaging range and the projection range each define a major axis and a minor axis whose length is smaller than the major axis. The projection unit projects the light beam along an incident path toward the object to be measured, and the light beam enters the imaging unit along a reflection path after being reflected by the object to be measured. The projection of the incident path on the plane to be measured is parallel to the extension direction of the minor axis of the projection range, or the projection of the reflection path on the plane to be measured is parallel to the extension direction of the minor axis of the imaging range.

The processing unit is electrically connected to the projection unit and the imaging unit. After receiving a trigger signal, the processing unit drives the projection unit to project the light beam and drives the imaging unit to receive the light beam reflected from the object to be measured.

In some implementations, the processing unit drives the projection unit to project the light beam for a projection period, and drives the imaging unit to receive the reflected light beam for an imaging period.

In some implementations, the processing unit drives the projection unit to project the light beam for a continuous projection period, and drives the imaging unit to receive the reflected light beam at the start of imaging.

In some implementations, the imaging range and the projection range are quadrilaterals, wherein a line connecting the centers of two pairs of sides defines the major axis, and a line connecting the centers of the other two pairs of sides defines the minor axis.

In some implementations, the projection unit and the imaging unit define an effective imaging range, and the effective imaging range is larger than the imaging range.

In some implementations, the effective imaging range defined by the projection unit and the imaging unit is related to the distance between the projection unit and the object to be measured, the distance between the imaging unit and the object to be measured, and the angle between the projection unit and the imaging unit.

In some embodiments, half of the side length of the effective imaging range defined by the projection unit and the imaging unit Wherein, R1 is the distance between the projection unit and the object to be measured, R2 is the distance between the imaging unit and the object to be measured, and θ is the angle between the projection unit and the imaging unit.

In some implementations, the projection range is larger than and includes the imaging range, and the effective imaging range defined by the projection unit and the imaging unit is larger than and includes the imaging range.

One of the objectives of the present invention is to provide an optical detection method for improving detection efficiency.

In some embodiments, the optical detection method of the present invention is suitable for measuring an object to be measured disposed on a plane to be measured using an optical device, wherein the optical device comprises a projection unit for projecting a light beam to the object to be measured and defining a projection range, and an imaging unit for receiving a light beam reflected from the object to be measured and defining an imaging range, wherein the projection unit and the imaging range each define a major axis and a minor axis whose length is less than the major axis, and the optical detection method comprises the following steps:

Measuring steps: the projection unit projects a light beam toward the object to be measured along an incident path, and after being reflected by the object to be measured, the light beam enters the imaging unit along a reflection path, and the projection of the incident path on the plane to be measured is parallel to the extension direction of the short axis of the projection range, or the projection of the reflection path on the plane to be measured is parallel to the extension direction of the short axis of the imaging range.

In some implementations, the projection range and the imaging range are quadrilaterals, wherein a line connecting the centers of two pairs of sides defines the major axis, and a line connecting the centers of the other two pairs of sides defines the minor axis.

In some implementations, the projection unit and the imaging unit define an effective imaging range, and the effective imaging range is larger than the imaging range.

In some implementations, the effective imaging range defined by the projection unit and the imaging unit is related to the distance between the projection unit and the object to be measured, the distance between the imaging unit and the object to be measured, and the angle between the projection unit and the imaging unit.

In some embodiments, half of the side length of the effective imaging range defined by the projection unit and the imaging unit Wherein, R1 is the distance between the projection unit and the object to be measured, R2 is the distance between the imaging unit and the object to be measured, and θ is the angle between the projection unit and the imaging unit.

In some implementations, the projection range is larger than and includes the imaging range, and the effective imaging range defined by the projection unit and the imaging unit is larger than and includes the imaging range.

Another object of the present invention is to provide an optical device design method for improving the detection efficiency of the optical device.

In some embodiments of the optical device design method of the present invention, the optical device includes a projection unit for projecting a light beam to the object to be measured and defining a projection range, and an imaging unit for receiving a light beam reflected from the object to be measured and defining an imaging range, wherein the imaging range defines a major axis and a minor axis whose length is less than the major axis. The optical device design method includes a calculation step, a judgment step, and a measurement step.

The calculation step calculates an effective imaging range according to the distance between the projection unit and the object to be measured, the distance between the imaging unit and the object to be measured, and the angle between the projection unit and the imaging unit.

The judging step judges whether the imaging range is not greater than the side length of the effective imaging range according to the effective imaging range calculated in the calculating step, and if the judging result is yes, proceeds to the next step.

In the measuring step, the projection unit projects a light beam toward the object to be measured along an incident path, and after being reflected by the object to be measured, the light beam enters the imaging unit along a reflection path, and the projection of the incident path or the reflection path on the plane to be measured is parallel to the extension direction of the short axis.

In some implementations, a setting step is also included: adjusting at least one of the distance between the projection unit and the object to be measured, the distance between the imaging unit and the object to be measured, and the angle between the projection unit and the imaging unit. If the result of the judgment step is no, the setting step and the calculation step are performed.

The present invention has the following effects: when the object to be measured is a rectangular parallelepiped or a similar long object, since the effective imaging range in which local overexposure does not occur is only related to the direction parallel to the incident path or the reflection path, and has nothing to do with the direction perpendicular to the incident path or the reflection path, therefore, by designing the optical path so that the projection of the incident path or the reflection path on the plane to be measured is parallel to the extension direction of the short axis, the user only needs to consider placing the short side of the object to be measured within the effective imaging range, and there will be no local overexposure phenomenon, so that the effective observation area of the imaging can be increased, thereby improving the measurement efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the accompanying drawings, in which:

FIG1 is a photograph showing an overexposure condition during measurement by a conventional three-dimensional detection instrument;

2 and 3 are schematic side views of the prior art three-dimensional detection apparatus in different settings;

FIG4 is a top view of the effective area and the DUT corresponding to the configuration of FIG2 ;

FIG5 is a top view schematically showing the effective area and the DUT under the arrangement corresponding to FIG3 ;

FIG6 is a block diagram of an optical device of the present invention;

7 is a flow chart of an embodiment of an optical device design method of the present invention;

FIG8 is a schematic side view of the optical device;

FIG9 is a schematic top view corresponding to FIG8;

FIG10 is a top view of another embodiment;

FIG11 is a schematic diagram of the optical path of the optical device;

12 to 14 are relationship diagrams drawn according to the calculation formulas used in the calculation steps of the embodiment;

15A and 15B are top view schematic diagrams respectively illustrating the situations of detecting I/O components using the conventional detection method and the optical detection method of the present invention.

DETAILED DESCRIPTION

Referring to Figures 6, 8 and 9, an embodiment of the optical device design method of the present invention, the optical device 2 comprises a projection unit 21 for projecting a light beam to an object to be measured 23 and defining a projection range 24, an imaging unit 22 for receiving the light beam reflected from the object to be measured 23 and defining an imaging range 25, and a processing unit 26 electrically connected to the projection unit 21 and the imaging unit 22.

Referring to FIG8, FIG9 and FIG10, in one of the implementation modes of the present embodiment, a projection range 24 of the projection unit 21 on the plane to be measured is a quadrilateral, specifically a rectangle, and an imaging range 25 of the imaging unit 22 on the plane to be measured is a quadrilateral, specifically a trapezoid with two sides parallel. It should be supplemented that the length of a pair of parallel sides in the aforementioned trapezoid varies according to the projection direction, and the scope of the present invention is not limited thereto. In other modes of the present embodiment, if the incident surface of the projection unit 21 is not perpendicular to the projection surface, the projection range 24 is a quadrilateral (no two sides are parallel). Referring to FIG10, in another variation of the present embodiment, the positions of the projection unit 21 and the imaging unit 22 are interchanged. It should also be supplemented that, in the present embodiment, the projection range 24 will include and cover the imaging range 25, but it should not be limited thereto. It is further explained that the projection range 24 and the imaging range 25 each define a long axis and a short axis whose length is shorter than the long axis, wherein the center line of two pairs of sides defines the long axis, and the center line of the other two pairs of sides defines the short axis.

An effective imaging range 20 is defined as a range extending outward by Δ from the projection center O of the projection unit 21 on the measured plane, wherein a local overexposure point that complies with the law of reflection and enters the imaging unit 22 is formed at a distance Δ from point O.

It is additionally noted that the light beam may be, but is not limited to, structured light. The projection unit 21 may include one or more projectors (not shown), and the imaging unit 22 may include one or more camera lenses (not shown).

Specifically, in this embodiment, the object to be tested 23 is a highly reflective material with a flat surface, for example, an object to be tested 23 with a mirror surface, in one implementation of this embodiment, the object to be tested 23 is entirely composed of a highly reflective material, and in other implementations of this embodiment, the surface of the object to be tested 23 is a highly reflective material. However, the material of the object to be tested 23 is not limited to the above.

6 and 8 , the processing unit 26 drives the projection unit 21 to project the light beam after receiving a trigger signal, and drives the imaging unit 22 to receive the light beam reflected from the object to be measured 23 .

In this embodiment, the processing unit 26 is an external computer. In other variations of this embodiment, the processing unit 26 may also be a motherboard with a central processing unit, such as but not limited to the Raspberry Pi developed by the British Raspberry Pi Foundation. The processing unit 26 may be connected to an input device (not shown, such as a keyboard, button, etc.) through a signal to receive the trigger signal. The trigger signal may be a key signal from a computer keyboard, or may be from another automated control device electrically connected to the processing unit 26, but is not limited thereto.

In one implementation of the present embodiment, the lens of the image capturing unit 22 is automatically closed, the processing unit 26 drives the projection unit 21 to project a light beam for a continuous projection period, and drives the image capturing unit 22 to receive the reflected light beam at the beginning of the image capturing time. Specifically, considering the stability of the light beam of the projection unit 21, the processing unit 26 first drives the projection unit 21 to turn on, and then drives the image capturing unit 22 to turn on and receive the reflected light beam at the beginning of the image capturing time after the light beam is stable. When the lens of the image capturing unit 22 is automatically closed at the end of the exposure time, the processing unit 26 controls the projection unit 21 to be closed.

In another implementation of the present embodiment, the opening and closing of the image capturing unit 22 are all controlled by the processing unit 26, that is, the processing unit 26 drives the projection unit 21 to project the light beam for the continuous projection period, and drives the image capturing unit 22 to receive the reflected light beam for a continuous image capturing period. Preferably, considering the light beam stability of the projection unit 21, the processing unit 26 first drives the projection unit 21 to open, and then drives the image capturing unit 22 to open and receive the reflected light beam for the continuous image capturing period after the light beam is stable, and then controls to close the image capturing unit 22 and the projection unit 21 in sequence.

7 , 8 and 9 , the optical device design method includes a setting step 101 , a calculation step 102 , a determination step 103 , and a measurement step 104 .

<Setting steps>

At least one of the distance between the projection unit 21 and the object to be measured 23 , the distance between the imaging unit 22 and the object to be measured 23 , and the angle between the projection unit 21 and the imaging unit 22 is adjusted.

In one implementation of this embodiment, the setting step 101 refers to re-setting the optical device 2 .

<Calculation steps>

The calculation step 102 is to calculate the effective imaging range 20 by using the distance between the projection unit 21 and the object to be measured 23 , the distance between the imaging unit 22 and the object to be measured 23 , and the angle between the projection unit 21 and the imaging unit 22 .

Specifically, the calculation step 102 uses the equation 1: Wherein, Δ is half of the side length of the effective imaging range 20 , R ₁ is the distance between the projection unit 21 and the object to be measured 23 , R ₂ is the distance between the imaging unit 22 and the object to be measured 23 , and θ is the angle between the projection unit 21 and the imaging unit 22 .

Specifically, half of the side length of the effective imaging range 20 refers to the distance between the boundary of the effective imaging range 20 and the projection center of the projection unit 21 on the plane to be measured.

It is to be supplemented that the derivation process of the operation formula 1 is shown in FIG11 . First of all, it should be noted that point O is the center of the object to be measured 23, point A is the lens center of the projection unit 21, point B is the lens center of the imaging unit 22, and point C is the reflection position of the light beam in accordance with the law of reflection, that is, Symmetrical line segment The vertical line (normal line) passing through point C is used as the axis of symmetry. Point D is the position of point B symmetrically with the horizontal line as the axis of symmetry. Point E is The intersection of the extended line and the horizontal line passing through point D. In addition, The length of the line segment is △ (half the length of the side of the effective imaging range 20). The length of the line segment is R ₁ , The length of the line segment is R ₂ .

Since △CAO and △DAE are similar triangles, therefore, By converting the trigonometric function, Δ×(R ₁ +R ₂ ×cosθ)=R ₁ ×R ₂ sinθ, the calculation formula 1 is obtained.

According to the calculation formula used in the calculation step 102, we obtain the data in the following table, where, in the implementation of this embodiment, R1 = 300mm, R2 = 270mm, 300mm, 319.5mm and 360mm, that is, R1: R2 are 1: 0.9, 1: 1, 1: 1.065, 1: 1.2 respectively. Where Φ is the angle between the boundary of the projection unit 21 to the effective imaging range 20 and a vertical line passing through the center of the projection unit (i.e. ∠OAC in FIG. 11 )

From the above table and Figures 12 to 14, we can understand that the relationship between Φ and θ, Δ and Φ, and Δ and θ are all linear between θ = 20° and 30°, and the standard deviation R ² of each trend line in Figures 11 to 13 is all equal to 1, indicating that the relationship between Φ, θ and Δ is easy to accurately predict. Therefore, in one of the implementations of this embodiment, the linear relationship calculation formula between the three can also be pre-stored in the aforementioned processing unit (not shown). When the user adjusts and changes the angle θ between the projection unit 21 and the imaging unit 22, the aforementioned linear relationship calculation formula can be directly used for calculation. Compared with the aforementioned calculation formula 1, it can save computing resources and improve computing efficiency.

<Judgment Step 103>

According to the effective imaging range 20 calculated in the calculation step 102 , it is determined whether the imaging range 25 is not larger than the effective imaging range 20 . If the determination result is yes, the measurement step 104 described later is performed.

If the result of the determination step 103 is no, the process returns to the setting step 101 and the calculation step 102 .

It is additionally noted that, since the effective imaging range 20 can be calculated through the calculation step 102 , the effective imaging range can also be designed to be larger than the projection range 24 , depending on the needs of the user.

It is further explained that the calculation step 102 and the judgment step 103 can be calculated manually or performed using a processing unit (not shown) of the optical device 2. For example, the processing unit receives parameters (R1, R2, θ) from an input component (not shown) and performs calculations based on a pre-stored equation 1.

<Measurement Step 104>

The projection unit 21 projects a light beam toward the object 23 along an incident path, and after being reflected by the object 23 , the light beam enters the imaging unit 22 along a reflection path. The projection of the reflection path on the plane to be measured is parallel to the extension direction of the short axis of the imaging range 25 .

Referring to FIG. 10 , in another embodiment of the present invention, the positions of the projection unit 21 (see FIG. 8 ) and the imaging unit 22 (see FIG. 8 ) are interchanged, so that the projection of the incident path on the plane to be measured is parallel to the extension direction of the short axis of the projection range 24 .

Since Δ in equation 1 is only related to R1, R2, and θ, that is, the effective imaging range 20 is only related to the direction parallel to the incident path or the reflected path, and has nothing to do with the direction perpendicular to the incident path or the reflected path. Therefore, when the surface of the object to be tested 23 is a rectangle or other strip with an aspect ratio not equal to one, the user only needs to consider placing the short side 231 to be tested of the object to be tested 23 (see FIG. 15B ) within the effective imaging range, so that the short side 231 to be tested of the object to be tested 23 is all within the effective imaging range 20, which can increase the effective observation area of imaging, thereby improving measurement efficiency. Preferably, if the effective imaging range 20 is designed to include and cover the projection range 24 or the imaging range 25, the user can perform the detection as long as the size of the object to be tested 23 is within the projection range 24 or the imaging range 25.

It is further explained that, under the same size of the object to be measured (i.e., the size of the object to be measured 13 in FIG. 4 is equal to the size of the object to be measured 23 in this embodiment) and the same effective imaging range (the effective range 16 in FIG. 4 is equal to the effective imaging range 20 in this embodiment, i.e., D1 in FIG. 4 is equal to Δ in FIG. 9 ), using the measurement steps of this embodiment, the entire imaging range 25 can be located within the effective imaging range 20, so there will be no local overexposure, thereby solving the measurement problem caused by local overexposure.

Specifically, the following situations may occur during use:

1. When the side length of the imaging range 25 calculated in the calculation step 102 is not greater than the side length of the effective imaging range 20 (i.e., the judgment result of the judgment step 103 is yes), the measurement step 104 can be performed. Next, if the short side 231 of the object 23 to be measured is smaller than the side length of the effective imaging range 20, the measurement step 104 can be performed.

2. When the side length of the imaging range 25 calculated in the calculation step 102 is smaller than the side length of the effective imaging range 20 (i.e., the judgment result of the judgment step 103 is no), the setting step 101 is performed, and the user can adjust at least one of the distance between the projection unit 21 and the object to be measured 23, the distance between the imaging unit 22 and the object to be measured 23, and the angle between the projection unit 21 and the imaging unit 22 to expand the effective imaging range 20 so that the short side 231 to be measured of the object to be measured 23 is located within the effective imaging range 20. Then, the measuring step 104 can be performed. Next, if the short side 231 to be measured of the object to be measured 23 is smaller than the side length of the effective imaging range 20, the measuring step 104 can be performed.

It is worth noting that, after the optical device 2 is designed by the aforementioned optical device design method, it can be provided to the inspection industry for an optical inspection method. The optical inspection method is suitable for using the optical device 2 to measure the object to be measured 23 set on the plane to be measured, and only includes the aforementioned measurement step 104.

In summary, the optical device, optical detection method and optical device design method of the present invention, since the effective imaging range 20 without local overexposure is only related to the direction parallel to the incident path or the reflection path, and has nothing to do with the direction perpendicular to the incident path or the reflection path, therefore, by designing the optical path so that the projection of the incident path or the reflection path on the plane to be measured is parallel to the extension direction of the short axis of the imaging range 25 or the projection range 24, the user only needs to consider placing the short side of the object to be measured 23 within the effective imaging range 20, so that local overexposure will not occur, the effective observation area of the imaging is increased, and the measurement efficiency is improved, so the purpose of the present invention can be achieved.

It should be supplemented that, due to the increasing demand for electronic component inspection, and because the material of the electrical contacts is mostly copper or other highly conductive metals, the optical properties of their surfaces are similar to the characteristics of mirrors, resulting in the aforementioned local overexposure phenomenon. In addition, we also understand that the imaging noise occurs at the electrical contact boundary parallel to the projection (or imaging) direction. Referring to Figures 15A and 15B, the object to be tested 23 is an electronic component and has a plurality of electrical contacts 230 in the form of long strips. In order to make the object to be tested 23 have more electrical contacts 230 to improve its computing performance, the length extension direction of each electrical contact 230 is parallel to the short side 231 of the object to be tested 23. Referring to Figure 15A, if the detection method of the prior art is adopted, the projection of the reflection path on the plane to be tested is perpendicular to the extension direction of the short axis of the imaging range 25, and its signal-to-noise ratio (SNR) will be positively correlated to 15B, however, if the optical detection method of the present invention is adopted, since the projection of the reflection path on the plane to be measured is parallel to the extension direction of the short axis of the imaging range 25, the signal-to-noise ratio (SNR) will be positively correlated to In summary, when the optical detection method of the present invention is used to detect the object to be detected 23, the signal-to-noise ratio (SNR) can be effectively improved and the proportion of noise can be reduced.

The above are only embodiments of the present invention and should not be used to limit the scope of the present invention. That is, any simple equivalent changes and modifications made according to the claims and description of the present invention are still within the scope of the present invention.

Claims (16)

1. An optical device suitable for measuring an object to be measured, comprising: the optical device includes:

the projection unit is used for projecting a light beam to the object to be detected and defining a projection range;

The image capturing unit is used for receiving the light beam reflected by the object to be detected and defining an image capturing range, the image capturing range and the projection range respectively define a long axis and a short axis with the length smaller than the long axis, the projection unit projects the light beam towards the object to be detected along an incident path, the light beam is reflected by the object to be detected and enters the image capturing unit along a reflection path, and the projection of the incident path on a plane to be detected is parallel to the extending direction of the short axis of the projection range, or the projection of the reflection path on the plane to be detected is parallel to the extending direction of the short axis of the image capturing range; and

The processing unit is electrically connected with the projection unit and the image capturing unit, and drives the projection unit to project the light beam after receiving the trigger signal and drives the image capturing unit to receive the light beam reflected by the object to be detected.

2. The optical device of claim 1, wherein: the processing unit drives the projection unit to project the light beam for a continuous projection period, and drives the image capturing unit to receive the reflected light beam for an image capturing period.

3. The optical device of claim 1, wherein: the processing unit drives the projection unit to project the light beam for a continuous projection period, and drives the image capturing unit to receive the reflected light beam at the time of starting image capturing.

4. The optical device of claim 1, wherein: the image capturing range and the projection range are quadrangles, wherein the central connecting lines of two opposite sides define the long axis, and the central connecting lines of the other two opposite sides define the short axis.

5. The optical device of claim 1, wherein: the projection unit and the image capturing unit define an effective image capturing range, and the effective image capturing range is larger than the image capturing range.

6. The optical device of claim 1, wherein: the effective image capturing range defined by the projection unit and the image capturing unit is related to the distance between the projection unit and the object to be detected, the distance between the image capturing unit and the object to be detected, and the included angle between the projection unit and the image capturing unit.

7. The optical device of claim 1, wherein: half of the side length of the effective image capturing range defined by the projection unit and the image capturing unitWherein R1 is the distance between the projection unit and the object to be detected, R2 is the distance between the projection unit and the object to be detected, and θ is the included angle between the projection unit and the image capturing unit.

8. The optical device of claim 1, wherein: the projection range is larger than and comprises the image capturing range, and the effective image capturing range defined by the projection unit and the image capturing unit is larger than and comprises the image capturing range.

9. An optical detection method, suitable for measuring an object to be measured disposed on a plane to be measured by using an optical device, the optical device includes a projection unit for projecting a light beam to the object to be measured and defining a projection range, and an image capturing unit for receiving the light beam reflected from the object to be measured and defining an image capturing range, the image capturing range and the projection range each define a long axis and a short axis with a length smaller than the long axis, and the optical detection method is characterized in that: the optical detection method comprises the following steps:

the measuring step comprises the following steps: the projection unit projects light beams towards the object to be detected along an incident path, the light beams are reflected by the object to be detected and enter the image capturing unit along a reflection path, and the projection of the incident path on the plane to be detected is parallel to the extending direction of the short axis of the projection range, or the projection of the reflection path on the plane to be detected is parallel to the extending direction of the short axis of the image capturing range.

10. The optical detection method according to claim 9, wherein: the image capturing range and the projection range are quadrangles, wherein the central connecting lines of two opposite sides define the long axis, and the central connecting lines of the other two opposite sides define the short axis.

11. The optical detection method according to claim 9, wherein: the projection unit and the image capturing unit define an effective image capturing range, and the effective image capturing range is larger than the image capturing range.

12. The optical detection method according to claim 9, wherein: the effective image capturing range defined by the projection unit and the image capturing unit is related to the distance between the projection unit and the object to be detected, the distance between the image capturing unit and the object to be detected, and the included angle between the projection unit and the image capturing unit.

13. The optical detection method according to claim 9, wherein: half of the side length of the effective image capturing range defined by the projection unit and the image capturing unitWherein R1 is the distance between the projection unit and the object to be detected, R2 is the distance between the image capturing unit and the object to be detected, and θ is the included angle between the projection unit and the image capturing unit.

14. The optical detection method according to claim 9, wherein: the projection range is larger than and comprises the image capturing range, and the effective image capturing range defined by the projection unit and the image capturing unit is larger than and comprises the image capturing range.

15. An optical device design method, the optical device includes a projection unit for projecting a light beam to an object to be measured and defining a projection range, and an image capturing unit for receiving the light beam reflected from the object to be measured and defining an image capturing range, the image capturing range defining a long axis and a short axis having a length smaller than the long axis, the optical device design method is characterized in that: the optical device design method comprises the following steps:

The calculation steps are as follows: calculating an effective image capturing range according to the distance between the projection unit and the object to be detected, the distance between the image capturing unit and the object to be detected and the included angle between the projection unit and the image capturing unit;

judging: judging whether the image capturing range is not larger than the effective image capturing range according to the effective image capturing range calculated in the calculating step, if so, carrying out the next step;

The measuring step comprises the following steps: the projection unit projects light beams towards the object to be detected along an incident path, the light beams are reflected by the object to be detected and enter the image capturing unit along a reflecting path, and the projection of the incident path or the reflecting path on the plane to be detected is parallel to the extending direction of the short axis.

16. The method of designing an optical device according to claim 15, wherein: the method further comprises the setting step of: and adjusting at least one of the distance between the projection unit and the object to be detected, the distance between the image capturing unit and the object to be detected and the included angle between the projection unit and the image capturing unit, and if the result of the judging step is negative, performing the setting step and the calculating step.