Surface topography detection system
By using a light pattern generator and lens group to form a tilted and intersecting projection focal plane pattern in the surface topography inspection system, the problems of short optical depth of field and long inspection time are solved, and efficient surface topography inspection is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BENANO INC
- Filing Date
- 2024-12-09
- Publication Date
- 2026-06-09
Smart Images
Figure CN122170805A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a surface morphology detection system, and more particularly to a surface morphology detection system that projects periodic patterns onto a test object to detect variations in the surface structure of the test object. Background Technology
[0002] In advanced semiconductor packaging, wafer bump quality (bump position and height) is a crucial aspect of process control, thus requiring bump quality inspection (i.e., inspection of the bump surface morphology). Existing surface morphology inspection systems typically employ optical measurement methods. However, as bump sizes shrink, extremely high optical resolution is required, resulting in a very short optical depth of field. Consequently, given unavoidable wafer warping, accurately focusing on the bumps for inspection becomes extremely difficult.
[0003] In semiconductor packaging production lines, surface topography inspection systems such as reflective triangulation or structured illumination microscopy (SIM) are typically used for full wafer inspection. Because reflective triangulation requires an angle between the light source's incident direction and the sensor's receiving direction, the light source can only be incident from the side, resulting in a shadow effect. On the other hand, see... Figure 1A The existing structured lighting microscopy technique projects a focal plane pattern P' (e.g., a sine wave pattern) parallel to the horizontal direction and perpendicular to the height direction onto the surface 200 of an object using a projector, and then captures an image of the focal plane pattern P' projected onto the object surface 200 using a camera. The horizontal range of the focal plane pattern P' is illustrated by examples from horizontal position X1 to horizontal position X15, and the field of view (FOV) 201 of the camera is illustrated by examples such as the range from horizontal position X1 to horizontal position X8, and the range from horizontal position X9 to horizontal position X15. The structured lighting microscopy technique operates by first remaining stationary in the horizontal direction and then scanning along the height direction, forming multiple focal plane patterns P'1 to P'8 corresponding to height positions Y1 to Y8 respectively. After the focal plane patterns P'1 to P'8 are captured by the camera, a suitable calculation method is selected based on the pattern characteristics of the focal plane pattern P' to calculate focusing parameters, such as sine wave amplitude, light intensity, and gradient, but not limited to these, to obtain... Figure 1BThe focus index curve at horizontal position X2 is used, and the height value of the object surface 200 at horizontal position X2 is determined by the highest point of the focus index curve, which is then used to determine the value at height position Y4. Similarly, by calculating the focus index of each image, focus index curves corresponding to different horizontal positions X1 to X8 can be obtained to acquire the height information of the object surface 200 at horizontal positions X1 to X8. Furthermore, since the length of the object surface 200 in the horizontal direction exceeds the camera's visible area 201, after acquiring the height information of one of the visible areas 201, the structured lighting micro-technology needs to move horizontally to the next consecutive visible area 201 to continue scanning in the height direction to completely scan the object surface 200. Therefore, it can be seen that the existing structured lighting micro-technology requires repeated stopping and starting in both the horizontal and height directions, resulting in excessively long detection time. While it can be used for sampling tests, it cannot meet the production capacity requirements for online inspection. Summary of the Invention
[0004] The purpose of this invention is to provide a surface morphology detection system that can solve at least one of the aforementioned problems.
[0005] This invention discloses a surface topography detection system suitable for bearing surfaces parallel to a first scanning direction. The system includes a light pattern generator, a sensor, and a lens assembly. The light pattern generator includes a light pattern generating surface that is not parallel to the first scanning direction. The light pattern generating surface is capable of emitting a periodic patterned light beam with varying brightness. The sensor includes a sensing surface capable of sensing light. The lens assembly is aligned with the light pattern generating surface and the sensor. The periodic patterned light beam emitted by the light pattern generating surface is projected perpendicularly onto the bearing surface through the lens assembly, forming a projection focal plane pattern that intersects the first scanning direction at an angle. The sensor then images the projection focal plane pattern onto the sensing surface through the lens assembly.
[0006] In the surface topography detection system of the present invention, the light pattern generating surface and the sensing surface form an optical conjugate surface through the lens group.
[0007] The surface topography detection system of the present invention is suitable for measuring the test surface of an object. The object is placed on a support surface. The surface topography detection system further includes a control and computing unit. The light pattern generator and the object are movable relative to each other in a first scanning direction. The control and computing unit is electrically connected to the light pattern generator and the sensor. The control and computing unit can control the light pattern generator to continuously project a projection focal plane pattern when the light pattern generator and the object are movable relative to each other in the first scanning direction, and control the sensor to form an image of the continuously projected projection focal plane pattern on the sensing surface through the lens.
[0008] The surface topography detection system of the present invention uses a microdisplay as the light pattern generator. The microdisplay is capable of controlling the display of periodic patterned light beams with different patterns.
[0009] The surface morphology detection system of the present invention wherein the projected focal plane pattern is one of the following: a sine wave pattern, a striped pattern, an array of circular holes, a honeycomb-shaped arrangement of holes, and a checkerboard pattern.
[0010] The surface topography detection system of the present invention includes a lens group comprising a first lens unit. The first lens unit defines a first optical axis aligned with the light pattern generating surface. The first optical axis is inclined relative to the light pattern generating surface. The periodic patterned light beam emitted from the light pattern generating surface passes through the lens group and is projected by the first lens unit.
[0011] In the surface morphology detection system of the present invention, the first lens unit is a long focal length object-side telecentric lens or a bidirectional telecentric lens.
[0012] The surface topography detection system of the present invention has a first optical axis perpendicular to the first scanning direction. The lens group further includes a beam splitter aligned with the light pattern generating surface and the sensing surface and located on the extension line of the first optical axis. The beam splitter allows light emitted from the light pattern generating surface to pass through and reflects the projected focal plane pattern onto the sensing surface.
[0013] In the surface topography detection system of the present invention, the first optical axis is parallel to the first scanning direction. The lens group further includes a beam splitter aligned with the light pattern generating surface and the sensing surface and located on the extension line of the first optical axis. The beam splitter reflects the light emitted by the light pattern generating surface toward the bearing surface and allows the projected focal plane pattern to pass through to the sensing surface.
[0014] The surface topography detection system of the present invention further includes a second lens unit in the lens group. The second lens unit defines a second optical axis aligned with the sensing surface via the beam splitter. Both the first lens unit and the second lens unit are long focal length object-side telecentric lenses or bidirectional telecentric lenses.
[0015] In the surface morphology detection system of the present invention, the periodic pattern beam emitted by the light pattern generating surface has a projection focal plane pattern that changes periodically along the first scanning direction.
[0016] The surface topography detection system of the present invention includes a light pattern generator comprising a grating having a light pattern generating surface. The grating allows light to pass through and emits the periodic patterned light beam.
[0017] The surface topography detection system of the present invention further includes a light-emitting device, wherein the light-emitting device is used to emit a colored light beam onto the bearing surface, and the sensor is capable of receiving the colored light beam reflected by the surface to be tested.
[0018] In the surface morphology detection system of the present invention, the light-emitting device is an angle lamp, and the colored light beam emitted by the light-emitting device is tilted towards the bearing surface.
[0019] The beneficial effects of this invention are as follows: By projecting the periodic patterned light beam along the height direction perpendicular to the first scanning direction, the occlusion problem can be avoided; in addition, by setting the light pattern generating surface to be non-parallel to the first scanning direction to form the projection focal plane pattern that intersects with the first scanning direction at an angle, it can intersect with the test surface of the object under test at different horizontal positions and different heights. This allows the surface topography detection system to obtain height data at different horizontal positions without vertical scanning, simply by continuously acquiring images along the first scanning direction and performing image reconstruction calculations. This reduces the number of stops and starts of the surface topography detection system, thereby improving detection efficiency. Attached Figure Description
[0020] Figure 1A A schematic diagram illustrating how existing structured lighting techniques scan in the height direction and project multiple projection focal plane patterns relative to the object surface.
[0021] Figure 1B for Figure 1A The focus index curve corresponding to the horizontal position X2;
[0022] Figure 2 This is a schematic diagram illustrating an embodiment of the surface morphology detection system of the present invention applied to the detection of the test surface of a test object;
[0023] Figure 3 This is a block diagram illustrating the connection relationship between the described embodiment and the driving device;
[0024] Figure 4 This is a schematic diagram illustrating another embodiment of the lens assembly described in the present invention;
[0025] Figure 5 This is a schematic diagram illustrating another embodiment of the lens assembly;
[0026] Figure 6A This is a schematic diagram illustrating the embodiment of scanning along a first scanning direction and projecting multiple projection focal plane patterns relative to the surface under test;
[0027] Figure 6B for Figure 6AThe focus index curve corresponding to the horizontal position X2;
[0028] Figure 7A This is a schematic diagram showing that the periodic patterned beam emitted by the light pattern generator of the embodiment appears as a sine wave pattern on the projection focal plane;
[0029] Figure 7B This is a schematic diagram showing the periodic patterned beam of light appearing as an array of circular holes on the projection focal plane;
[0030] Figure 7C This is a schematic diagram showing the periodic patterned light beam appearing as a honeycomb-shaped pattern of holes on the projection focal plane;
[0031] Figure 7D This is a schematic diagram showing the periodic patterned light beam as a striped pattern on the projection focal plane;
[0032] Figure 7E This is a schematic diagram showing the periodic patterned light beam appearing as a checkerboard pattern on the projection focal plane. Detailed Implementation
[0033] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.
[0034] See Figure 2 , Figure 3 This is one embodiment of the surface topography detection system of the present invention. The surface topography detection system is suitable for measuring a test surface 91 with one side facing upwards on a test object 9, thereby detecting the three-dimensional topography of the test surface 91. The test object 9 is, for example, a wafer with bumps, but not limited thereto, and is placed on a support surface 300 parallel to a first scanning direction X and a second scanning direction Z perpendicular to the first scanning direction X. The support surface 300 can be the top surface of a stage (not shown) and can be driven by a driving device 400 to move in the first scanning direction X and / or the second scanning direction Z, so that the test object 9 and the surface topography detection system move relative to each other in the first scanning direction X and / or the second scanning direction Z. However, in other embodiments, the support surface 300 may be fixed and immovable, and the driving device 400 is mounted on the surface topography detection system and can drive the surface topography detection system to move, so that the test object 9 and the surface topography detection system move relative to each other.
[0035] See Figure 2 and Figure 7AThe surface topography detection system is suitable for measuring the height change of the test surface 91 of the test object 9 in a height direction Y perpendicular to the first scanning direction X and the second scanning direction Z, and includes a light pattern generator 1, a sensor 2, a lens group 3, and a control computing unit 4 electrically connected to the light pattern generator 1, the sensor 2, and the driving device 400. The light pattern generator 1 includes a light pattern generating surface 11 that is not parallel to the first scanning direction X. The light pattern generating surface 11 can emit a periodic pattern beam P with brightness variations, and project a projection focal plane pattern P' with brightness variations onto a projection focal plane of the lens group 3. Furthermore, the projection focal plane pattern P' varies periodically along the first scanning direction X. For example, the light pattern generator 1 is a microdisplay (e.g., a display panel) electrically connected to the control computing unit 4, so that the microdisplay can be controlled by the control computing unit 4 and display the periodic pattern beam P with different patterns according to the settings received by the control computing unit 4. However, the light pattern generator 1 can also be a light pattern generator 1 equipped with a light source (not shown) and a grating (not shown). The grating has the light pattern generating surface 11 and can be a photomask or film made by means of developing, writing, or photocopying. The light emitted by the light source of the light pattern generator 1 passes through the grating to generate a beam of light corresponding to the grating pattern. In this way, the user can replace the grating with different shapes according to actual needs, so that the pattern projected by the periodic pattern beam P can be changed according to the requirements.
[0036] See Figures 7A to 7E The periodic patterned beam P can be projected onto a plane to present a pattern as shown in the image. Figure 7A The sine wave pattern shown, such as Figure 7B The array of circular holes shown, such as Figure 7C The honeycomb-like arrangement of holes shown, such as Figure 7D The striped pattern shown is similar to... Figure 7E One type of checkerboard pattern is shown. In this embodiment, the periodic patterned beam P is an example of a string wave pattern resembling light and dark stripes when projected onto a plane.
[0037] See Figure 2The sensor 2 is, for example, a camera, but not limited thereto. The sensor 2 is capable of being tilted and includes a sensing surface 21 capable of sensing light. The sensing surface 21 is, for example, a photosensitive film of a camera, but not limited thereto. The sensing surface 21 forms an imaging focal plane via the lens group 3, and is coplanar with the projection focal plane formed by the light pattern generating surface 11 via the lens group 3, such that the sensing surface 21 and the light pattern generating surface 11 form an optical conjugate plane through the lens group 3. Furthermore, the sensor 2 and the light pattern generator 1 can be interchanged in the first scanning direction X and the height direction Y, and the sensor 2 or the light pattern generator 1 is aligned with the object under test 9.
[0038] See Figure 2 The lens group 3 is aligned with the light pattern generating surface 11 and the sensing surface 21. Specifically, the lens group 3 includes a first lens unit 31, a beam splitter 32, and a second lens unit 33. The first lens unit 31 is provided with a plurality of first lenses 312 whose optical centers are aligned with each other. Figure 2 (Two examples are given below) to define a first optical axis 311 aligned with the light pattern generating surface 11. Furthermore, the first optical axis 311 may be parallel to the first scanning direction X or the height direction Y. In this embodiment, the first optical axis 311 is perpendicular to the first scanning direction X and parallel to the height direction Y, and is relatively inclined to the light pattern generating surface 11. In this way, the periodic patterned light beam P emitted from the light pattern generating surface 11 passes through the first lens unit 31 along the direction of the first optical axis 311, and is projected perpendicularly onto the bearing surface 300, forming the projection focal plane pattern P' on the projection focal plane of the first lens unit 31, such that the projection focal plane pattern P' intersects the first scanning direction X at an inclined angle.
[0039] Furthermore, the first lens unit 31 is a telecentric lens with a long focal length or a bidirectional telecentric lens, preferably with a large aperture.
[0040] The beam splitter 32 allows light to travel in two different directions and is located between the light pattern generator 1 and the sensor 2. That is, the beam splitter 32 is aligned with the light pattern generating surface 11 and the sensing surface 21 and is located on the extension line of the first optical axis 311. In this embodiment, the test object 9, the beam splitter 32, and the light pattern generator 1 are arranged sequentially along the height direction Y, and the sensor 2 is offset from the light pattern generator 1 in the height direction Y. The light emitted by the light pattern generating surface 11 can pass through the beam splitter 32 and illuminate the test surface 91 of the test object 9. The projected focal plane pattern P' illuminating the test surface 91 of the test object 9 is first reflected by the test surface 91 of the test object 9 to the beam splitter 32, and then reflected by the beam splitter 32 to be imaged onto the sensing surface 21. However, in other embodiments (not shown), the object under test 9, the beam splitter 32, and the sensor 2 can be arranged sequentially along the height direction Y, with the light pattern generator 1 offset from the sensor 2 in the height direction Y, and the first optical axis 311 parallel to the first scanning direction X. In this way, the light emitted by the light pattern generating surface 11 is first transmitted to the beam splitter 32 in the first scanning direction X. Then, the light emitted by the light pattern generating surface 11 is reflected by the beam splitter 32 to the bearing surface 300 and projected onto the test surface 91 of the object under test 9. It is then reflected by the test surface 91 of the object under test 9 back to the beam splitter 32 and re-imaged onto the sensing surface 21 by the beam splitter 32. That is to say, the positions of the light pattern generator 1 and the sensor 2 can be interchanged, depending on the actual needs.
[0041] See Figure 2 , Figure 4 and Figure 5 The beam splitter 32 can be as follows: Figure 2 As shown, it is located between the first lens unit 31 and the object under test 9, or as... Figure 4 As shown, the beam splitter 32 is located between the first lens unit 31 and the light pattern generator 1. It can also be located between the two first lenses of the first lens unit 31. The beam splitter 32 can be aligned with both the light pattern generating surface 11 and the sensing surface 21 at the same time, and is not limited to a specific position.
[0042] See Figure 2 , Figure 4 and Figure 5The second lens unit 33 is used to image the projected focal plane pattern P' onto the sensing surface 21. The second lens unit 33 is, for example, a long-focal-length object-side telecentric lens or a bi-directional telecentric lens, preferably with a large aperture to improve efficiency and accuracy, but is not limited thereto. The second lens unit 33 defines a second optical axis 331 aligned with the center of the sensing surface 21 via the beam splitter 32 and perpendicular to the first optical axis 311, and has a plurality of second lenses 332. Furthermore, the optical magnification of the second lens unit 33 may differ from that of the first lens unit 31. In this embodiment, the second lens unit 33 is similar to the first lens unit 31, both being examples of lens groups with two lenses, but... Figure 4 In this embodiment, the second lens unit can be replaced by the first lens unit 31. That is, the light reflected by the beam splitter 32 will be directly imaged on the sensing surface 21. Furthermore, in... Figure 5 In this embodiment, the second lens unit 33 can also share a lens with the first lens unit 31. In other words, in Figure 5 In the embodiment, the lens group 3 includes a first lens 312, a beam splitter 32, a second lens 332, and a shared lens 34. The periodic patterned light beam P emitted from the light pattern generating surface 11 projects the projection focal plane pattern P' through the first lens unit 31, which is composed of the first lens 312 and the shared lens 34; the sensor 2 then images the projection focal plane pattern P' onto the sensing surface 21 through the second lens unit 33, which is composed of the second lens 332 and the shared lens 34, and the beam splitter 32.
[0043] See Figure 2 , Figure 3 and Figure 6A The control and calculation unit 4 is, for example, a computer but not limited thereto, and can control the drive device 400 to move the light pattern generator 1 and the object under test 9 relative to each other in the first scanning direction X. The control and calculation unit 4 can control the light pattern generator 1 to continuously project the projection focal plane pattern P' when the light pattern generator 1 and the object under test 9 move relative to each other in the first scanning direction X, and control the sensor 2 to image the continuously projected projection focal plane pattern P' on the sensing surface 21 through the lens group 3.
[0044] The following describes in detail the detection method of the surface morphology detection system of the present invention. (Refer to...) Figure 6AAs shown above, the surface topography detection system scans along the first scanning direction X and projects multiple projection focal plane patterns P'1 to P'15 that are not parallel to the first scanning direction X (i.e., obliquely intersecting). Each projection focal plane pattern P'1 to P'15 may include a range from position Y1 to position Y8 in the height direction Y. The surface topography detection system moves along the first scanning direction X to continuously acquire images, wherein, with Figure 7A Taking a sine wave pattern as an example, the phase of each of the projected focal plane patterns P'1 to P'8 can be changed using the phase shift method; if we take Figures 7B to 7E Taking the pattern of each periodic patterned beam P as an example, the projection focal plane patterns P'1 to P'8 can adopt the same pattern as appropriate. After the surface topography detection system continuously acquires images and the images are reconstructed by the control calculation unit, for example, by using the image at position X2 of the projection focal plane patterns P'2 to P'9 to calculate the focus index, the following can also be obtained: Figure 6B The height can be determined by the focusing index curve. Alternatively, the height can be determined by detecting position X3 in the projected focal plane pattern P'3 to P'10. In this way, the surface topography detection system does not need to perform the height direction Y scan (i.e., vertical scan), and can continuously capture images along the first scanning direction X to continuously extend the range of the visible area A (which can be regarded as a continuous visible area), thereby reducing the number of repeated stops and starts and greatly improving scanning efficiency.
[0045] See Figure 3 Preferably, the surface topography detection system further includes a light-emitting device 5 located above the bearing surface 300 and electrically connected to the control computing unit 4. The light-emitting device 5 is, for example, an angle lamp, used to emit a colored light beam (not shown) onto the bearing surface 300. The colored light beam is, for example, a red beam, a green beam, a blue beam, or a combination thereof. The colored light beam emitted by the light-emitting device 5 is angled towards the bearing surface 300.
[0046] In summary, by projecting the periodic patterned light beam P along the height direction Y, which is perpendicular to the first scanning direction X, the projected focal plane pattern P' can be perpendicularly irradiated onto the test surface 91 of the test object 9 in an inclined state relative to the test object 9, thereby avoiding occlusion problems and increasing the imaging depth of field. Furthermore, by setting the light pattern generating surface 11 to be non-parallel to the first scanning direction X, a projected focal plane pattern P' that intersects with the first scanning direction at an inclined angle can be formed, intersecting with the test surface 91 of the test object 9 at different horizontal positions and heights. This allows the surface topography detection system to obtain height data at different horizontal positions without vertical scanning, simply by continuously acquiring images along the first scanning direction X and performing image reconstruction calculations. This reduces the number of stops and starts in the surface topography detection system, thereby improving detection efficiency and achieving the objectives of this invention.
Claims
1. A surface morphology inspection system, applicable to a bearing surface parallel to a first scanning direction; characterized in that: The surface topography detection system includes: A light pattern generator includes a light pattern generating surface that is not parallel to the first scanning direction, the light pattern generating surface being capable of emitting a periodic patterned light beam with varying brightness. The sensor includes a sensing surface capable of sensing light; and The lens assembly is aligned with the light pattern generating surface and the sensor. The periodic patterned light beam emitted from the light pattern generating surface is projected vertically onto the bearing surface through the lens group to form a projection focal plane pattern that intersects with the first scanning direction at an angle, and the sensor images the projection focal plane pattern onto the sensing surface through the lens group.
2. The surface morphology detection system according to claim 1, characterized in that: The light pattern generating surface and the sensing surface form an optical conjugate surface through the lens group.
3. The surface morphology detection system according to claim 1, characterized in that: The surface topography detection system is suitable for measuring the test surface of an object to be tested. The object to be tested is placed on the support surface. The surface topography detection system also includes a control and calculation unit. The light pattern generator and the object to be tested can move relative to each other in the first scanning direction. The control and calculation unit is electrically connected to the light pattern generator and the sensor. The control and calculation unit can control the light pattern generator to continuously project the projection focal plane pattern when the light pattern generator and the object to be tested move relative to each other in the first scanning direction, and control the sensor to form an image of the continuously projected projection focal plane pattern on the sensing surface through the lens.
4. The surface morphology detection system according to claim 1, characterized in that: The light pattern generator is a microdisplay, which can controllably display periodic pattern beams with different patterns.
5. The surface morphology detection system according to claim 4, characterized in that: The projected focal plane pattern is presented as one of the following: a sine wave pattern, a striped pattern, an array of circular holes, a honeycomb-shaped arrangement of holes, and a checkerboard pattern.
6. The surface morphology detection system according to claim 1, characterized in that: The lens group includes a first lens unit that defines a first optical axis aligned with the light pattern generating surface. The first optical axis is inclined relative to the light pattern generating surface. The periodic pattern beam emitted from the light pattern generating surface passes through the lens group and is projected by the first lens unit.
7. The surface morphology detection system according to claim 6, characterized in that: The first lens unit is a long focal length object-side telecentric lens or a bidirectional telecentric lens.
8. The surface morphology detection system according to claim 6, characterized in that: The first optical axis is perpendicular to the first scanning direction. The lens group further includes a beam splitter aligned with the light pattern generating surface and the sensing surface and located on the extension line of the first optical axis. The beam splitter allows light emitted from the light pattern generating surface to pass through and reflects the projected focal plane pattern to the sensing surface.
9. The surface morphology detection system according to claim 6, characterized in that: The first optical axis is parallel to the first scanning direction. The lens group further includes a beam splitter aligned with the light pattern generating surface and the sensing surface and located on the extension line of the first optical axis. The beam splitter reflects the light emitted by the light pattern generating surface toward the bearing surface and allows the projected focal plane pattern to pass through to the sensing surface.
10. The surface morphology detection system according to claim 8, characterized in that: The lens group further includes a second lens unit, which defines a second optical axis aligned with the sensing surface via the beam splitter. Both the first lens unit and the second lens unit are long-focal-length object-side telecentric lenses or bi-directional telecentric lenses.
11. The surface morphology detection system according to claim 1, characterized in that: The periodic patterned beam emitted from the light pattern generating surface has a projected focal plane pattern that changes periodically along the first scanning direction.
12. The surface morphology detection system according to claim 1, characterized in that: The light pattern generator includes a grating having the light pattern generating surface, the grating being able to allow light to pass through and emit the periodic pattern beam.
13. The surface morphology detection system according to claim 3, characterized in that: The surface topography detection system also includes a light-emitting device for emitting a colored light beam onto the bearing surface, and the sensor is capable of receiving the colored light beam reflected by the surface under test.
14. The surface morphology detection system according to claim 13, characterized in that: The light-emitting device is an angle lamp, and the colored light beam emitted by the light-emitting device is tilted towards the bearing surface.