Optical system
A compact optical system design for eye-tracking devices integrates a camera unit and LFI sensor on a shared substrate with a shared optical window and light guidance, addressing space inefficiencies and reducing packaging costs while enhancing energy efficiency.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- ROBERT BOSCH GMBH
- Filing Date
- 2025-10-08
- Publication Date
- 2026-05-15
AI Technical Summary
Existing optical systems incorporating eye-tracking devices are not compact and space-efficient, leading to inefficiencies in design and increased packaging costs.
A combined housing for a camera unit and laser feedback interferometer (LFI) sensor, integrated on a shared substrate, with a compact optical design that includes a shared optical window and light guidance unit, allowing for efficient space utilization and energy-saving operation through controlled activation of the camera unit based on eye movement detection.
The solution achieves a more compact and cost-effective optical system design with improved space utilization and energy efficiency by minimizing hardware components and optimizing power consumption.
Smart Images
Figure EP2025078892_15052026_PF_FP_ABST
Abstract
Description
[0001] R.414943
[0002] - 1 -
[0003] Description
[0004] Optical system
[0005] The invention relates to an optical system. Furthermore, the invention relates to eyeglasses incorporating the optical system.
[0006] State of the art
[0007] Document DE 10 2022 211 128 A1 discloses a hybrid eye-tracking device comprising a camera sensor and a laser feedback interferometer sensor (LFI sensor).
[0008] Based on this, it is an object of the present invention to make such a sensor module more compact and space-saving.
[0009] Disclosure of the invention
[0010] To solve the problem, an optical system according to claim 1 is proposed. Furthermore, a pair of glasses according to claim 14 is proposed.
[0011] The optical system comprises a first camera unit, a first laser feedback interferometer (LFI) sensor, and a housing. The housing serves as a combined enclosure for the first camera unit and the first LFI sensor. In particular, the housing protects the first camera unit and the first LFI sensor from the external environment. This combined housing allows for a more compact design of the sensor module, resulting in packaging cost savings.
[0012] Preferably, the optical system additionally comprises a substrate on which the first camera unit, in particular a camera chip of the first camera unit, and the first LFI sensor are located, in particular directly adjacent to each other. The substrate is in particular designed as a silicon substrate. Alternatively, R.414943
[0013] - 2 - the substrate is designed as a circuit board. The shared substrate saves space and allows for the easy integration of common electronic components, particularly cables, into the housing. Preferably, the substrate forms one side, particularly a bottom, of the housing of the optical system. Preferably, the first camera unit, particularly the camera chip of the first camera unit, has a rectangular cross-section and is bonded to the substrate. The first LFI sensor is located at a first corner of the first camera unit. No bond wires are present at the corners of the camera chip, thus providing space for the LFI sensor to be positioned as close as possible to the camera chip. This maximizes space savings.
[0014] Preferably, the housing of the optical system includes an optical window, particularly a shared one, for directing ambient light towards the first camera unit and for directing a first light beam emitted by the first LFI sensor into an environment, particularly an external one, surrounding the optical system. Preferably, the optical window also serves to direct the first light beam reflected from an object, particularly a user's eye, towards the first LFI sensor. Preferably, the optical window is an optical lens. The optical lens preferably has a first and a second segment with different focal lengths. The first segment is assigned to the first LFI sensor and the second segment to the first camera unit. This allows for different focal lengths for the first LFI sensor and the first camera unit.
[0015] Preferably, the optical system additionally comprises a light guidance unit, particularly an elongated one, especially in the form of a transparent light tube. The light guidance unit is configured to couple the first light beam emitted by the first LFI sensor and to couple the first light beam into an environment, particularly an external one, surrounding the optical system. In particular, the light guidance unit is configured to couple the first light beam in the direction of the eye of a user of the optical system. The light guidance unit offers the possibility of shaping the first light beam in a targeted manner, particularly as a point. Preferably, the light guidance unit is R.414943
[0016] - 3 - The imaging unit is designed to couple the first light beam in a ring shape into the surroundings of the optical system. This allows a ring-shaped illumination to be projected onto the user's eye, which can then be captured by the first camera unit. The captured distortion of the ring can, for example, be used to infer the orientation of the eye or the direction of gaze using an eye-tracking algorithm.
[0017] Preferably, the first LFI sensor is configured to emit initial light beams toward the user's eye at defined time intervals. Furthermore, the optical system includes a control unit designed to detect changes in the user's eye state based on the initial light beams emitted by the first LFI sensor and the initial light beams reflected back from the user's eye. These changes in eye state primarily involve eye movement. The control unit is further configured to send an initial control signal, specifically a control signal to activate the first camera unit, based on the detected change in the user's eye state. This allows for energy savings.The camera unit, for example, is only switched on from power-saving standby mode by the control unit when a change in the eye's state can be detected. The LFI signals from the first LFI sensor can thus be used to control the first camera unit.
[0018] Preferably, the optical system additionally includes a bandpass filter designed to allow only light rays in an infrared wavelength range from the surroundings of the optical system to pass towards the first camera unit. Consequently, the first camera unit only sees light rays in the wavelength range of the first light rays from the first LFI sensor.
[0019] Preferably, the optical system additionally includes a second camera unit and a second LFI sensor. The housing serves as a common enclosure, particularly for protection from the external environment, for the first camera unit, the first LFI sensor, the second camera unit, and the second LFI sensor. The first camera unit and / or the first LFI sensor are R.414943.
[0020] - 4 - is configured to capture the user's eye from a first position, in particular from a first perspective, within the housing. The second camera unit and / or the second LFI sensor is configured to capture the user's eye from a second position, in particular from a second perspective, within the housing. Preferably, the control unit of the optical system is configured to generate a stereo image of the user's eye from the LFI signals and / or camera signals. The setup in such a stereo system allows triangulation of the absolute position of the eye in 3D using the LFI sensors. Furthermore, the pupil can be reconstructed in 3D from the two camera images. Preferably, the two sensor systems are connected via a flexible cable, thus minimizing the cabling effort and allowing the two sensor systems to be synchronized.
[0021] Another object of the present invention is a pair of glasses with the optical system described above. The glasses are particularly designed as data glasses or virtual reality glasses.
[0022] Description of the drawings
[0023] Figures 1a and 1b show a first embodiment of the optical system.
[0024] Figure 2 shows a second embodiment of the optical system.
[0025] Figure 3 shows a possible arrangement of the LFI sensors relative to the camera chip.
[0026] Figure 4 shows a third embodiment of the optical system.
[0027] Description of the exemplary implementations
[0028] Figure 1a schematically shows a first embodiment of an optical system 50a. The optical system 50a comprises a first camera unit 10, a first laser feedback interferometer sensor (LFI sensor) 9, and a housing 18. The housing 18 is here referred to as a common housing, in particular R.414943
[0029] - 5 - designed for protection against an external environment, for the first camera unit 10 and the first LFI sensor 9. In particular, the housing is designed as the camera housing of the first camera unit 10.
[0030] The first embodiment of the optical system 50 further comprises a substrate 11 on which the first camera unit 10, in particular a camera chip of the first camera unit, and the first LFI sensor 9 are arranged, in particular directly adjacent to each other.
[0031] Furthermore, the housing 18 of the optical system 50a has an optical window 7, in particular a common one, for directing ambient light 21a towards the first camera unit 10 and for directing a first light beam 20a emitted by the first LFI sensor into the vicinity of the optical system 50a. In addition, the optical window 7 also serves to direct the first light beam 20b reflected from an ambient object, in particular a user's eye, towards the first LFI sensor 9. In this case, the optical window 7 is an optical lens. This lens has a first segment 8a and a second segment 8b with different focal lengths. The first segment 8a is assigned to the first LFI sensor 9 and the second segment 8b to the first camera unit 10.
[0032] In this first embodiment of the optical system 50a, an optical element 14 for shaping the first light beam 20a is arranged in the emission direction upstream of the first LFI sensor 9. In this case, the optical element 14 is designed as a metalenser.
[0033] Furthermore, in this embodiment, the optical system 50a has an additional bandpass filter 19, which is designed to allow only light rays 21a in an infrared wavelength range from the vicinity of the optical system 50a to pass in the direction of the first camera unit 10.
[0034] Figure 1b shows the optical system 50a, in which the optical system 50a, in particular the first camera unit 10 and the first LFI sensor 9 of the optical system 50a, is used to detect the gaze direction of a user of the optical system. R.414943
[0035] - 6 - terns 50a is formed. In this context, the eye 1 of the user of the optical system 50a with pupil 3 lies within a detection area 2 of the first camera unit. Furthermore, the first light beam 20a of the first LFI sensor is also emitted onto a point 5 of the user's eye 1.
[0036] In this first embodiment, the first LFI sensor 9 is configured to emit the first light beams 20a towards the user's eye 1 at defined time intervals. As shown in Figure 1a, the optical system 50a has an additional control unit 12, which is arranged at the bottom of the substrate 11 and is configured to detect a change in the eye state of the user's eye 1, in particular a movement of the user's eye 1, depending on the first light beams 20a emitted by the first LFI sensor 9 and the first light beams 20b reflected back from the user's eye 1. In this context, the control unit 12 is further configured to send a first control signal, in particular a control signal to switch on the first camera unit 10, to the first camera unit 10 depending on the detected change in the eye state of the user's eye 1.Thus, the camera unit 10 can, for example, initially be in a power-saving standby mode and only be switched on when there is a change in the eye's condition.
[0037] In this first embodiment, the optical system 50a is integrated into a partially shown spectacle frame 31. The spectacles, not shown here for simplicity, are designed as either data glasses or, alternatively, as virtual reality glasses.
[0038] Figure 2 shows a second embodiment of an optical system 50b. In contrast to the first embodiment, the optical system 50b additionally comprises a light guidance unit 17, in particular an elongated one. The light guidance unit 17 is designed in the form of a transparent light tube. The light guidance unit 17 is configured to couple the first light beam 20c emitted by the first LFI sensor 9 and to couple the first light beam 20d into the vicinity of the optical system 50b, in particular in the direction of an eye (not shown) of a user of the optical system. Optionally, the light guidance unit 17 is configured to R.414943
[0039] - 7 - det, to couple the first light beam 20d in a ring shape into the vicinity of the optical system 50b.
[0040] Figure 3 shows a sectional view of a first camera chip 13 with a rectangular cross-section, arranged on a substrate 12b of the optical system. The first camera chip 13 is firmly bonded to the substrate 12b. An LFI sensor 22a, 22b, 22c, and 22d is arranged at each corner of the first camera chip 13. Space is available in the immediate vicinity of the first camera chip for the LFI sensors 22a, 22b, 22c, and 22d, as no bond wires are located there.
[0041] Figure 4 schematically shows a third embodiment of an optical system 50c. In contrast to the previous embodiments, the optical system 50c comprises, in addition to the first camera unit 33 and the first LFI sensor 37a, a second camera unit 32 and a second LFI sensor 37b. The housing 45 serves as a common enclosure, particularly for protection from the external environment, for the first camera unit 33, the first LFI sensor 37a, the second camera unit 32, and the second LFI sensor 37b. The first camera unit 33 and the first LFI sensor 37a are configured to detect the user's eye 1 from a first position within the housing 45. For this purpose, the first LFI sensor 37a emits a first light beam 40 onto a first point 36 of the user's eye. The first camera unit 33 has a detection range 34 within which the user's eye 1 is located.The second camera unit 32 and the second LFI sensor 37b are configured to detect the user's eye 1 from a second position within the housing 45. For this purpose, the second LFI sensor 37b emits a second light beam 42 onto a second point 36 of the user's eye 1. The second camera unit 32 also has the detection area 34 within which the user's eye 1 is located. Furthermore, the optical system 50c includes a control unit 44, in particular a central one, which is configured to generate a stereo image, in particular a three-dimensional one, of the user's eye 1 from the LFI signals and camera signals.
[0042] In this third embodiment of the optical system 50c, the first camera unit 33 and the first LFI sensor 37a have an associated first opti- R.414943
[0043] - 8 - window 30 and the second camera unit 32 and the second LFI sensor 37b share an associated second optical window 31. The first camera unit 33, the first LFI sensor 37a, the second camera unit 32 and the second LFI sensor 37b are arranged on a common substrate 43 of the common housing 45. The substrate 43 also forms the bottom of the common housing 45.
Claims
R.414943 - 9 - Claims 1. Optical system (50a, 50b, 50c), comprising at least - a first camera unit (10, 33), - a first LFI sensor (9, 22a, 22b, 22c, 22d, 37a), and - a housing (18, 45), characterized in that the housing (18, 45) serves as a common housing, in particular for protection against an external environment, for the first camera unit (10, 33) and the first LFI sensor (9, 22a, 22b, 22c, 22d, 37a).
2. Optical system (50a, 50b, 50c) according to claim 1 , characterized in that the optical system (50a, 50b, 50c) additionally comprises a substrate (11 , 12b, 43) wherein the first camera unit (10, 33), in particular a camera chip (13) of the first camera unit (10, 33), and the first LFI sensor (9, 22a, 22b, 22c, 22d, 37a), in particular directly adjacent to each other, are arranged on the substrate (11 , 12b, 43).
3. Optical system (50a, 50b, 50c) according to claim 2, characterized in that the first camera unit (10, 33), in particular the camera chip (13) of the first camera unit (10, 33), has a rectangular cross-section and is bonded to the substrate (11 , 12b, 43), wherein the first LFI sensor (9, 22a, 22b, 22c, 22d, 37a) is arranged at a first corner of the first camera unit (10, 33).
4. Optical system (50a, 50b, 50c) according to one of claims 1 to 3, characterized in that the housing (18, 45) of the optical system (50a, 50b, 50c) has an optical window (7), in particular a common one, for directing ambient light (21a) towards the first camera unit (10, 33) and for directing a first light beam (20a, 20c, 20d, 40) emitted by the first LFI sensor (9, 22a, 22b, 22c, 22d, 37a) into an environment of the optical system (50a, 50b, 50c). R.414943 - 10 - 5. Optical system (50a, 50b, 50c) according to claim 4, characterized in that the optical window (7) is an optical lens.
6. Optical system (50a, 50b, 50c) according to claim 5, characterized in that the optical lens has a first segment (8a) and a second segment (8b) with different focal lengths, wherein the first segment (8a) is assigned to the first LFI sensor (9, 22a, 22b, 22c, 22d, 37a) and the second segment (8b) is assigned to the first camera unit (10, 33).
7. Optical system (50a, 50b, 50c) according to one of claims 1 to 6, characterized in that the optical system (50a, 50b, 50c) additionally comprises a light guidance unit (17), in particular an elongated one, in particular in the form of a transparent light tube, wherein the light guidance unit (17) is configured to couple the first light beam (20a, 20c, 20d, 40) emitted by the first LFI sensor (9, 22a, 22b, 22c, 22d, 37a) into and to couple the first light beam (20a, 20c, 20d, 40) into an environment of the optical system (50a, 50b, 50c), in particular in a direction of an eye (1) of a user of the optical system (50a, 50b, 50c).
8. Optical system (50a, 50b, 50c) according to claim 7, characterized in that the light guidance unit (17) is configured to couple the first light beam (20a, 20c, 20d, 40) in a ring shape into the environment of the optical system (50a, 50b, 50c).
9. Optical system (50a, 50b, 50c) according to one of claims 1 to 8, characterized in that the optical system (50a, 50b, 50c), in particular the first camera unit (10, 33) and / or the first LFI sensor (9, 22a, 22b, 22c, 22d, 37a) of the optical system (50a, 50b, 50c), is designed to detect a gaze direction of a user of the optical system (50a, 50b, 50c).
10. Optical system (50a, 50b, 50c) according to claim 9, characterized in that the first LFI sensor (9, 22a, 22b, 22c, 22d, 37a) is designed to- R.414943 - 11 - is formed to emit first light rays (20a, 20c, 20d, 40) towards a user's eye (1) at defined time intervals, wherein the optical system (50a, 50b, 50c) additionally comprises a control unit (13, 44) which is configured to detect a change in the eye state of the user's eye (1), in particular a movement of the user's eye (1), depending on the first light rays (20a, 20b, 20c, 40) emitted by means of the first LFI sensor (9, 22a, 22b, 22c, 22d, 37a) and the first light rays (20a, 20b, 20c, 40) reflected back from the user's eye (1), wherein the control unit (13, 44) is additionally configured to determine the change in the eye state of the to send a first control signal, in particular a control signal to switch on the first camera unit (10,33) from the user eye (1) to the first camera unit (10,33).
11. Optical system (50a, 50b, 50c) according to one of claims 1 to 10, characterized in that the optical system (50a, 50b, 50c) additionally has a bandpass filter (19) which is configured to allow only light rays (21) in an infrared wavelength range from the environment of the optical system (50a, 50b, 50c) to pass in the direction of the first camera unit (10, 33).
12. Optical system (50a, 50b, 50c) according to any one of claims 1 to 11, characterized in that the optical system (50a, 50b, 50c) additionally comprises a second camera unit (32) and a second LFI sensor (37b), wherein the housing (18, 45) serves as a common housing, in particular for protection from the external environment, for the first camera unit (10, 33), the first LFI sensor (9, 22a, 22b, 22c, 22d, 37a), the second camera unit (32) and the second LFI sensor (37b), wherein the first camera unit (10, 33) and / or the first LFI sensor (9, 22a, 22b, 22c, 22d, 37a) is configured to detect the user's eye (1) from a first position within the housing (18, 45) from, and the second camera unit (32) and / or the second LFI sensor (37b) is designed to detect the user's eye (1) from a second position inside the housing (18, 45). R.414943 - 12 - 13. Optical system (50a, 50b, 50c) according to claim 12, characterized in that the control unit (13, 44) of the optical system (50a, 50b, 50c) is configured to generate a stereo image of the user's eye (1) from the LFI signals and / or camera signals.
14. Glasses, in particular data glasses or virtual reality glasses, with an optical system (50a, 50b, 50c) according to any one of claims 1 to 13.