Transmitter behind the monitor

Abstract

An optoelectronic device (20) includes a display (22) comprising a first substrate (45) transparent to optical radiation of a given wavelength; and a first array of display cells (30) comprising pixel circuit elements (32, 34, 38) disposed on the first substrate at a first pitch, with gaps (36) of a predefined size between the pixel circuit elements. An emitter array (40) includes a second substrate (51) parallel to and proximate to the first substrate; and a second emitter array (42) disposed on the second substrate at a second pitch different from the first pitch and configured to emit optical radiation of a given wavelength toward the first substrate. A control circuit (50) is configured to identify an emitter aligned with the gap between the pixel circuit elements and selectively drive the identified emitter to emit optical radiation through the gap.

Description

Technical Field

[0001] The present invention relates generally to optoelectronic devices, and more particularly to luminaires and displays. Background Art

[0002] Wearable and / or portable consumer devices, such as smartphones, augmented reality (AR) devices, virtual reality (VR) devices, and smart glasses, include optical displays as well as optical radiation sources. Summary of the Invention

[0003]

[0014] Embodiments of the invention described below provide improved designs and methods for integrating illuminators with displays.

[0004] Therefore, according to an embodiment of the present invention, there is provided an optoelectronic device comprising: a display comprising: a first substrate, the first substrate being transparent to optical radiation of a given wavelength; and a first display unit array, the first display unit array comprising pixel circuit elements disposed on the first substrate at a first spacing, with gaps of a predefined size between the pixel circuit elements. An emitter array comprising: a second substrate, the second substrate being parallel to and proximate to the first substrate; and a second emitter array, the second emitter array being disposed on the second substrate at a second spacing different from the first spacing and configured to emit optical radiation at the given wavelength toward the first substrate. A control circuit is configured to identify the emitter aligned with the gap between the pixel circuit elements and selectively drive the identified emitter to emit the optical radiation through the gap.

[0005] In the disclosed embodiment, the second spacing is smaller than the predefined size of the gap.

[0006] In some embodiments, the device includes a plurality of sensors of the optical radiation, the plurality of sensors being configured to detect the optical radiation emitted by the emitter and reflected from the pixel circuit element, wherein the control circuit is configured to identify the emitter in response to the reflected radiation detected by the sensor. Typically, the sensors are disposed on the second substrate. In one embodiment, the sensors are configured to detect a time of flight of the reflected radiation, and the control circuit is configured to distinguish the radiation reflected from the pixel circuit element in response to the detected time of flight. In this case, the sensors may include single photon avalanche diodes (SPADs).

[0007] Alternatively or additionally, the sensor is configured to detect an intensity of the reflected radiation, and the control circuit is configured to differentiate the radiation reflected from the pixel circuit element in response to the detected intensity.In a disclosed embodiment, the sensor comprises a photodiode.

[0008] Further additionally or alternatively, the control circuit is configured to identify the emitters that minimize the radiation reflected from the pixel circuit elements and selectively drive the identified emitters. In a disclosed embodiment, the control circuit is configured to actuate multiple groups of the emitters to continuously emit the optical radiation, measure the radiation reflected from the display by each of the multiple groups, and identify a group of emitters from the multiple groups of emitters to be selectively driven in response to the measured radiation.

[0009] In some embodiments, the emitters include microlenses configured to focus the optical radiation from each of the emitters to converge into a waist at the first substrate. In one embodiment, the second substrate includes a first side and a second side, wherein the emitters are formed on the first side of the second substrate and are configured to emit corresponding radiation beams through the second substrate, and wherein the microlenses are respectively formed on the second side of the second substrate in alignment with the emitters.

[0010] In the disclosed embodiment, the emitter comprises a vertical cavity surface emitting laser (VCSEL).

[0011] According to an embodiment of the present invention, a method for display is also provided, the method comprising: providing a display, the display comprising: a first substrate, the first substrate being transparent to optical radiation of a given wavelength; and a first display unit array, the first display unit array comprising pixel circuit elements disposed on the first substrate at a first pitch, with a gap of a predefined size between the pixel circuit elements. An emitter array is positioned so that the second substrate is parallel to and close to the first substrate, and the emitters emit the optical radiation toward the first substrate, the emitter array comprising: a second substrate; and a second emitter array, the second emitter array being disposed on the second substrate at a second pitch different from the first pitch and configured to emit optical radiation at the given wavelength. The emitter aligned with the gap between the pixel circuit elements is identified, and the emitter is selectively driven to emit the optical radiation through the gap.

[0012] The present invention will be more fully understood from the following detailed description of embodiments of the present invention when taken in conjunction with the accompanying drawings, in which: BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic front view of a portable device according to an embodiment of the present invention;

[0014] Figure 2 is a schematic front detail view of a display according to an embodiment of the present invention;

[0015] Figure 3 is superimposed on the VCSEL chip according to an embodiment of the present invention Figure 2 a schematic front detailed view of a display of;

[0016] Figure 4 According to an embodiment of the present invention Figure 3 Schematic front view of a VCSEL chip;

[0017] Figure 5 is a schematic cross-sectional view of a portion of an emitter array and a sensor and a display according to an embodiment of the present invention;

[0018] Figure 6 is a schematic diagram of a calibration method for selecting a VCSEL for actuation according to an embodiment of the present invention; and

[0019] Figure 7 is a schematic cross-sectional view of a VCSEL with integrated microlenses under a display according to another embodiment of the present invention. DETAILED DESCRIPTION

[0020] A wide variety of portable computing devices, such as smartphones, augmented reality (AR) devices, virtual reality (VR) devices, smartwatches, and smart glasses (collectively referred to in this specification as "portable devices"), include both optical displays and optical radiation sources. (As used in this specification and the claims, the terms "optical rays," "optical radiation," and "light" generally refer to any and all of visible radiation, infrared radiation, and ultraviolet radiation.) For example, the front of a smartphone may include a display screen, a camera for capturing an image of the user's face, and an illumination source for illuminating the face during image capture. The continued increase in the size, resolution, and brightness of the displays of these portable devices places severe constraints on the space available for the apertures of the various emitter and sensor modules within the front of these devices.

[0021] A display layout can be designed with a transparent window in the gap between pixel circuit elements within each pixel of the display. An emitter, such as a VCSEL (Vertical Cavity Surface Emitting Laser), placed behind and aligned with this window will emit a light beam through the window. Thus, an array of emitters behind the window array can provide illumination for applications in portable devices, such as 3D projection or facial recognition. However, efficient transmission of radiation through the windows requires aligning the emitters with the corresponding windows to an accuracy of a few microns. Mechanical alignment of this degree of precision between the emitter array and the display is very difficult, if not impossible, using currently available manufacturing methods.

[0022] Embodiments of the invention described herein address these problems by providing an optoelectronic device comprising a display having a given pixel pitch and an array of emitters mounted behind the display, the emitter pitch being different from the pixel pitch. Due to the difference in pitch, most of the emitters will not be aligned with the transparent window defined by the gaps between the pixel circuit elements, but some of the emitters will be aligned with the corresponding gaps. The control circuit identifies the emitters that are aligned with the gaps between the pixel circuit elements and selectively drives these emitters to emit their optical radiation through the gaps. The remaining emitters are typically not actuated (except perhaps during testing and calibration phases). Thus, the need for precise manufacturing alignment of the emitter array behind the display is eliminated.

[0023] In the disclosed embodiment, a display includes an array of display cells formed on a first substrate, such as a glass substrate, that is transparent to optical radiation at a wavelength emitted by an array of emitters. Each display cell includes one or more gaps between pixel circuit elements, thereby providing a window at the emitter wavelength. The array of emitters is formed on a second substrate, such as a semiconductor substrate, and is oriented so that the emitters emit optical radiation toward the first substrate, which is mounted parallel to and adjacent to the first substrate.

[0024] The pitch of the emitter array may advantageously be smaller than any of the lateral dimensions of the transparent windows in the display unit. In this case, some emitters are always aligned with the corresponding windows even with only a rough lateral mechanical alignment.

[0025] Various calibration procedures can be used to identify the emitters to be actuated and possibly change the selection in the field. (For example, such changes may be required due to movement of the alignment over time, particularly if the device experiences some mechanical shock.) To this end, in some embodiments, the emitter array also includes sensors, which can be scattered among the emitters or arranged in some other position on the second substrate, or can be placed on a separate substrate. The control circuit uses the sensors to measure the radiation from each emitter that is reflected back from the pixel circuit element toward the second substrate. Emitters aligned with the corresponding gaps have low back reflections and are identified as actuated on this basis. In one embodiment described in detail below, the control circuit measures the time between the emission of a pulse from the emitter and the detection of a photon at the sensor in order to identify short-range reflections that are characteristic of back reflections from the pixel circuit element.

[0026] Figure 1 is a schematic front view of a portable device 20 according to an embodiment of the present invention. The portable device 20 includes a display 22 that covers most of the front face of the portable device. The portable device 20 also includes an optical radiation source 24 that can be used for applications such as 3D projection or facial recognition. Embodiments of the present invention make it possible to place the source 24 behind the active portion of the display 22, as shown by the dashed box 26. This placement of the source 24 saves display area because otherwise the source would have to be placed in the notch area 28 (for other devices, such as cameras and other radiation sensors), thereby enlarging the notch and thus reducing the useful area of ​​the display 22.

[0027] Figure 2 2 is a schematic front view of a detail 29 of a display 22 according to an embodiment of the present invention. Display 22 includes a substrate 45, such as glass, which is transparent to optical radiation having wavelengths in the visible and near-infrared ranges. An array of display cells 30 is formed on substrate 45 by display manufacturing methods known in the art. Each display cell 30 includes a pixel circuit element, such as an OLED (organic light emitting diode) 32 and a TFT (thin film transistor) 34 for switching the OLED, disposed on substrate 45, and conductors 38 that connect the pixel circuit to electronics external to display 22.

[0028] The display cells 30 are spaced apart on the substrate 45 at a certain pixel pitch, with gaps 36 of predefined size defining transparent windows between the pixel circuit elements. In the illustrated example, the cells 30 have a W in the x direction. C,x = 80 μm pitch and has W in the y direction C,y = 60 μm. The size of the gap 36 is W W,x = 20 μm x width and W W,y=y width of 50 μm. The x-direction and the y-direction are indicated by the Cartesian coordinate axes 39 .

[0029] Detail 29 is presented merely as an example of a display cell 30 having a typical size gap 36. Other types of display cells having other layouts and sizes, as well as other types of pixel circuit elements, may be used, so long as they include sufficient gaps to function as transparent windows in each cell 30.

[0030] Figure 3 is a schematic diagram of detail 29 of display 22 superimposed over an array of emitters, such as a VCSEL chip 40, in accordance with an embodiment of the present invention. VCSELs 42a, 42b, 42c, and 42d on chip 40 are visible through respective gaps 36a, 36b, 36c, and 36d and are selectively driven to emit optical radiation through the respective gaps. A 2×2 matrix of VCSELs 42a, 42b, 42c, and 42d arranged in this manner can be used, for example, to provide illumination for a proximity sensor. In alternative embodiments, different arrangements and numbers of VCSELs 42 can be used.

[0031] Figure 4 According to an embodiment of the present invention Figure 3 Schematic front view of a VCSEL chip 40. The VCSEL chip 40 includes a matrix 43 of VCSELs 42 disposed on a substrate 51 such as a semiconductor substrate. The VCSELs 42a, 42b, 42c and 42d in the matrix 43 are Figure 3 36a, 36b, 36c and 36d in the matrix 43. These VCSELs are identified and selectively driven to emit optical radiation through the corresponding gaps 36, while the remaining VCSELs in the matrix 43 are not actuated.

[0032] In this example, the matrix 43 is laid out with equal pitch P in both the x and y dimensions, but other arrangements of emitters are possible. The pitch P is different from the size W of the gap 36. W,x or W W,y and advantageously smaller than the gap size to ensure that there will be at least one VCSEL 42 aligned with each gap. Figure 2 Given the dimensions given in FIG, pitch P can be selected to be about 10 μm or less. Selecting a pitch P that is much smaller than either of the two dimensions of gap 36 ensures that even rough lateral alignment tolerances between VCSEL chip 40 and display 22 will result in alignment of VCSEF 42 with each desired gap 36. (“Lateral alignment” refers to alignment in the plane of VCSEL chip 40.) In alternative embodiments, VCSELs 42 can be arranged with unequal pitches P in the x and y dimensions, respectively.x and P y In the matrix, P is required x <W W,x And P y <W W,y , where x and y again refer to Figure 2 The Cartesian coordinates of 39.

[0033] Figure 5 is a schematic cross-sectional view of a portion of an emitter and sensor array 44 and a display 22 in accordance with an embodiment of the present invention. The array 44 is positioned below the display 22, proximate to and parallel to the display. The array 44 includes multiple pairs of emitters (in this embodiment, VCSELs 42) and sensors (in this embodiment, SPADs (single photon avalanche diodes) 48) on a substrate 51. For simplicity, only two emitter / sensor pairs are shown - VCSELs 42e and 42f and SPADs 48e and 48f. The substrate 51 may include, for example, a silicon substrate with CMOS (complementary metal oxide semiconductor) circuitry for forming the SPAD 48 and for driving both the SPAD and VCSEL 42. Alternatively, other types of emitters and sensors may be used, and a given sensor may be shared among multiple emitters.

[0034] Control circuitry 50 is coupled to VCSELs 42 and SPADs 48. In the illustrated example, array 44 is positioned below display 22 such that a pair comprising VCSEL 42e and SPAD 48e is aligned with gap 36, while a pair comprising VCSEL 42f and SPAD 48f is not aligned with the gap. SPADs 48 detect optical radiation emitted by corresponding VCSELs 42 and reflected from pixel circuit elements (such as OLED 32, TFT 34, and conductor 38). Control circuitry 50 identifies emitters aligned with gap 36 based on the reflected radiation detected by the SPADs. Specifically, control circuitry 50 identifies VCSELs that minimize radiation reflected from pixel circuit elements and selectively drives these identified emitters. The remaining VCSELs 42 in array 44 are not driven and remain inactive. Circuitry that can be used for such selective VCSEL driving is described, for example, in U.S. Patent Application Publication 2019 / 0363520, the disclosure of which is incorporated herein by reference. This selective actuation scheme can be used to reduce the power consumed by the VCSEL chip, as well as reduce the amount of stray light reflected into device 20 .

[0035] like Figure 5As shown, VCSELs 42e and 42f emit respective beams 52e and 52f of optical radiation. Beam 52e is transmitted through gap 36 (above VCSEL 42e) into the space above display 22. Due to residual surface reflection from substrate 45 (typically a few percent), only a small portion of the beam is reflected toward SPAD 48e, as indicated by arrow 58. However, beam 52f is blocked by the pixel circuit elements, and thus the majority of beam 52f (except for a small portion that may be absorbed by the pixel circuit elements) is reflected toward SPAD 48f, as indicated by arrow 60. Therefore, based on the signals from sensors 48e and 48f, control circuit 50 can recognize and subsequently drive VCSEL 42e, but not VCSEL 42f.

[0036] While various types of sensors can be used to detect reflections from the display, SPADs 48 advantageously provide an output indicating the time of flight of photons emitted by VCSEL 42 and reflected back to the corresponding SPAD. Control circuitry 50 estimates the time of flight based on the time difference between each pulse applied to drive the VCSEL and the detection pulse output by the corresponding SPAD. Reflections from pixel circuit elements will be characterized by very short time of flight and can therefore be distinguished from reflections that may reach the SPAD from more distant objects in front of device 20.

[0037] In an alternative embodiment, the sensor of optical radiation includes an analog photodiode instead of SPAD 48. Control circuit 50 receives a signal from the photodiode via an analog-to-digital converter, for example, representing the integrated intensity of the reflected radiation. In this case, control circuit 50 will select the VCSEL whose reflected signal is weak, indicating that the VCSEL may be located behind gap 36.

[0038] To exploit this phenomenon to identify VCSELs 42 aligned with gap 36, control circuitry 50 continuously actuates multiple VCSELs or a collection of VCSELs 42 to emit optical radiation as a train of short pulses. Control circuitry 50 further receives and measures signals from SPADs 48 and calculates the flight times and number of received pulses. When the return pulses, indicated by arrows 58 and 60, return from display unit 30, the calculated flight times are equal, representing the round-trip distance from VCSEL 42 to the display and then to SPAD 48. However, because the reflectivity from substrate 45 at gap 36 is much lower than the reflectivity from pixel circuit elements (such as OLED 32 and TFT 34), the number of pulses with short flight times received by SPAD 48e will be much smaller than the number received by SPAD 48f. This difference in pulse counts provides control circuitry 50 with a means to identify those VCSELs 42 aligned with gap 36 based on minimized reflected radiation.

[0039] Figure 6 is a schematic diagram of a calibration method according to an embodiment of the present invention for identifying those VCSELs 42 that are aligned with the gap 36. The disclosed method comprises N consecutive steps, which are described in detail below. Figure 6 Steps 1, 2, 3 and N are shown, and the details of the method are shown in step 1.

[0040] A group of VCSELs 42 in the matrix 43 of the VCSEL chip 40 is defined by a unit cell 62 of four VCSELs 42g, 42h, 42i, and 42j, thereby forming a 2×2 matrix. (The four VCSELs forming the unit cell are marked by open circles.) The unit cell 62 also includes four SPADs 48, each of which is associated with one of the four VCSELs 42 in the unit cell (e.g., Figure 5 As shown, but for simplicity, Figure 6 The horizontal (x, y) dimension of the 2×2 matrix is ​​selected as the display unit 30 ( Figure 2 ) spacing W C,x and W C,y Since the spacing P of the matrix 43 is much smaller than the size W of the gap 36, W,x or W W,y , so at least one of the unit cells 62 will have its four VCSELs aligned with the corresponding gaps in the four corresponding display cells 30. (Even if the lateral dimension of the 2×2 matrix of unit cells 62 is not the pitch W C,x and W C,y However, since the spacing P is smaller, alignment is also an option.)

[0041] Figure 6 The purpose of the method is to identify one of unit cells 62 in VCSEL matrix 43 that is aligned with gap 36. The number of steps N is a function of the size of unit cell 62 and the number of VCSELs 42 in matrix 43. Although the present example uses a unit cell comprising a 2×2 matrix of VCSELs 42, unit cells comprising other numbers and arrangements of VCSELs may alternatively be used.

[0042] In each of the N steps of the method, the control circuit 50 defines a different position of the unit cell 62, i.e., the control circuit moves the unit cell across the matrix 43 in successive discrete steps of length P. At each step, the control circuit 50 drives the four VCSELs of the unit cell 62 to emit a short burst of optical radiation and receives pulses reflected from the display element 30 from the four SPADs 48 associated with the four VCSELs of the unit cell. The control circuit 50 calculates the total number of pulses from the four SPADs 48 of the unit cell 62 as a function of time, as shown in histogram 64. Pulses due to reflections from the display element 30 can be identified based on the short round-trip time between the VCSEL 42 and the SPAD, as marked by the dashed box 66.

[0043] Step 1 shows unit cell 62 in the upper left corner of matrix 43. In histogram 64, a large number of pulses are seen within box 66 (with a few stray pulses outside the box), indicating strong reflections back to the four SPADs 48 associated with the current position of unit cell 62. The strong reflections indicate that the four VCSELs in the current position of unit cell 62 are not aligned with gap 36, but rather that radiation emitted by the VCSELs impinges on pixel circuit elements in the corresponding display cell. This situation corresponds to Figure 5 The situation is shown by arrow 60 in FIG.

[0044] In step 2 , control circuitry 50 has shifted unit cell 62 to the right by one pitch interval P. Similar to step 1 , a large number of pulses are seen within box 66 , again indicating that VCSEL 42 of unit cell 62 is misaligned relative to gap 36 .

[0045] In step 3, control circuit 50 has moved unit cell 62 to the right by another pitch interval P. The number of pulses within box 66 is now significantly lower than the number of pulses in steps 1 and 2, indicating that the SPAD of unit cell 62 in the step 3 position has received optical radiation reflected from gap 36. In this position, the four VCSELs of the unit cell are aligned with gap 36. This situation corresponds to Figure 5 The situation is shown by arrow 58 in FIG.

[0046] In subsequent steps 4, 5, ... N, the number of return pulses may be further monitored to identify the optimal position of unit cell 62 with the minimum number of pulse counts within box 66. Control circuit 50 selects the VCSEL in this unit cell to be driven during operation of device 20.

[0047] although Figure 6 A somewhat simple strategy for identifying the best choice of VCSEL to drive is shown, but other more efficient search strategies may be used instead and are considered to be within the scope of the present invention.

[0048] Figure 7 is a schematic cross-sectional view of a VCSEL 70 having an integrated microlens 80 beneath display 22, according to another embodiment of the present invention. Microlens 80 focuses the optical radiation from VCSEL 70 to converge into waist 84 at substrate 45 of display 22 and thus pass cleanly through gap 36. Similar microlenses are formed in the beam path of each of the VCSELs in an emitter array, such as the VCSELs in matrix 33.

[0049] In the illustrated example, a VCSEL 70 is formed on a bottom surface 72 of a substrate 51 and emits optical radiation as a beam 76 into the substrate. The substrate 51 may comprise, for example, GaAs (gallium arsenide). A microlens 80 is formed on a top surface 78 of the substrate 51. This type of arrangement of a VCSEL with an integrated microlens is described, for example, in U.S. patent application Ser. No. 16 / 779,609, filed on February 2, 2020, the disclosure of which is incorporated herein by reference. Alternatively, other microlens arrangements known in the art may be used.

[0050] Microlens 80 transmits and refocuses light beam 76 into light beam 82 and projects it toward gap 36 in display 22. Microlens 80, along with VCSEL 70 and substrate 51, is designed and positioned so that waist 84 of light beam 82 is located at substrate 45. This design minimizes the cross-section of light beam 82 at gap 36, allowing the light beam to pass through the gap without being lost by impinging on pixel circuit elements at the gap edge. An anti-reflective coating 86 may be deposited on top surface 78 to reduce reflection losses from the top surface.

[0051] It should be understood that the embodiments described above are cited by way of example, and the present invention is not limited to what has been particularly shown and described above. On the contrary, the scope of the present invention includes the various features described above, as well as combinations and sub-combinations thereof, variations and modifications not disclosed in the prior art, which may occur to those skilled in the art after reading the above description.

Claims

1. A photoelectric device comprising: Display, including: a first substrate that is transparent to optical radiation of a given wavelength; and a first display unit array, the first display unit array comprising pixel circuit elements disposed on the first substrate at a first pitch, with gaps of a predefined size between the pixel circuit elements; Transmitter array, including: a second substrate parallel to and close to the first substrate; and a second emitter array disposed on the second substrate at a second pitch different from the first pitch and configured to emit optical radiation at the given wavelength toward the first substrate, wherein the emitter comprises a microlens configured to focus the optical radiation from each of the emitters to converge into a waist at the first substrate; and Control circuitry is configured to identify the emitter aligned with the gap between the pixel circuit elements and selectively drive the identified emitter to emit the optical radiation through the gap while the remaining emitters in the second emitter array are not actuated. 2 . The optoelectronic device of claim 1 , wherein the second spacing is smaller than the predefined size of the gap.

3. An optoelectronic device comprising: Display, including: a first substrate that is transparent to optical radiation of a given wavelength; and a first display unit array, the first display unit array comprising pixel circuit elements disposed on the first substrate at a first pitch, with gaps of a predefined size between the pixel circuit elements; Transmitter array, including: a second substrate parallel to and close to the first substrate; and a second emitter array disposed on the second substrate at a second pitch different from the first pitch and configured to emit optical radiation at the given wavelength toward the first substrate; a plurality of sensors for the optical radiation, the plurality of sensors being configured to detect the optical radiation emitted by the emitter and reflected from the pixel circuit elements; and control circuitry configured to identify the emitter aligned with the gap between the pixel circuit elements and selectively drive the identified emitter to emit the optical radiation through the gap, wherein the control circuit is configured to identify the emitter that minimizes the reflected radiation detected by the sensor, wherein the control circuit is configured to actuate multiple groups of the emitters to continuously emit the optical radiation, measure the radiation reflected from the display due to each of the multiple groups, and identify a group of emitters in the multiple groups of the emitters to be selectively driven in response to the measured radiation. The optoelectronic device of claim 3 , wherein the sensor is disposed on the second substrate.

5. The optoelectronic device of claim 3, wherein the sensor is configured to detect a time of flight of the reflected radiation, and the control circuit is configured to distinguish the radiation reflected from the pixel circuit element in response to the detected time of flight.

6. The optoelectronic device of claim 5, wherein the sensor comprises a single photon avalanche diode (SPAD).

7. The optoelectronic device of claim 3, wherein the sensor is configured to detect an intensity of the reflected radiation, and the control circuit is configured to differentiate the radiation reflected from the pixel circuit element in response to the detected intensity.

8. The optoelectronic device of claim 7, wherein the sensor comprises a photodiode.

9. The optoelectronic device of claim 3, wherein the emitter comprises a microlens configured to focus the optical radiation from each of the emitters to converge into a waist at the first substrate.

10. The optoelectronic device of claim 1 , wherein the second substrate comprises a first surface and a second surface, wherein the emitters are formed on the first surface of the second substrate and are configured to emit corresponding radiation beams through the second substrate, and wherein the microlenses are formed on the second surface of the second substrate in alignment with the emitters, respectively.

11. An optoelectronic device according to any one of claims 1 to 10, wherein the emitter comprises a vertical cavity surface emitting laser (VCSEL).

12. A method for displaying, comprising: A display is provided, the display comprising: a first substrate, the first substrate being transparent to optical radiation of a given wavelength; and a first display unit array, the first display unit array comprising pixel circuit elements disposed on the first substrate at a first pitch, with gaps of a predefined size between the pixel circuit elements; placing an emitter array comprising: a second substrate; and a second emitter array disposed on the second substrate at a second spacing different from the first spacing and configured to emit optical radiation at the given wavelength such that the second substrate is parallel to and proximate to the first substrate, and the emitters emit the optical radiation toward the first substrate, wherein the emitter comprises a microlens configured to focus the optical radiation from each of the emitters to converge into a waist at the first substrate; identifying the emitter aligned with the gap between the pixel circuit elements; and The identified emitters are selectively driven to emit the optical radiation through the gap, while the remaining emitters in the second array of emitters are not actuated. The method of claim 12 , wherein the second spacing is smaller than the predefined size of the gap.

14. The method of claim 12, wherein identifying the emitter comprises detecting the optical radiation emitted by the emitter and reflected from the pixel circuit element, and identifying the emitter in response to the reflected radiation.

15. The method of claim 14, wherein detecting the optical radiation comprises detecting a time of flight of the reflected radiation, and distinguishing the radiation reflected from the pixel circuit element in response to the detected time of flight.

16. The method of claim 14, wherein detecting the optical radiation comprises detecting an intensity of the reflected radiation, and distinguishing the radiation reflected from the pixel circuit element in response to the detected intensity.

17. The method of claim 14, wherein detecting the optical radiation comprises identifying the emitter that minimizes the radiation reflected from the pixel circuit element.

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