阅读说明：本技术 可调式光投射器 (Adjustable light projector ) 是由 陈宏山 陈明璿 于 2019-06-12 设计创作，主要内容包括：本发明提供一种可调式光投射器,包括光源、固定式光学相位调制器、可调式液晶面板及驱动器。光源用以发出光束。固定式光学相位调制器配置于光束的路径上,且用以调制光束的相位。可调式液晶面板配置于光束的路径上,且用以使光束在结构光与泛光之间切换。驱动器电性连接至可调式液晶面板的第一电极层与第二电极层,且用以改变第一电极层与第二电极层之间的电压差,进而使光束在结构光与泛光之间切换。(The invention provides an adjustable light projector, which comprises a light source, a fixed optical phase modulator, an adjustable liquid crystal panel and a driver. The light source is used for emitting light beams. The fixed optical phase modulator is configured on the path of the light beam and is used for modulating the phase of the light beam. The adjustable liquid crystal panel is configured on the path of the light beam and is used for switching the light beam between the structured light and the floodlight. The driver is electrically connected to the first electrode layer and the second electrode layer of the adjustable liquid crystal panel and is used for changing the voltage difference between the first electrode layer and the second electrode layer so as to switch the light beam between the structured light and the floodlight.)

1. An adjustable light projector, comprising:

a light source for emitting a light beam;

a fixed optical phase modulator disposed on a path of the light beam and configured to modulate a phase of the light beam;

an adjustable liquid crystal panel disposed on a path of the light beam and used for switching the light beam between a structured light and a flood light, the adjustable liquid crystal panel comprising:

a first substrate;

a second substrate;

a liquid crystal layer disposed between the first substrate and the second substrate;

a first electrode layer; and

a second electrode layer, wherein at least one of the first electrode layer and the second electrode layer is a patterned layer, and the first electrode layer and the second electrode layer are both disposed on one of the first substrate and the second substrate, or disposed on the first substrate and the second substrate, respectively; and

and the driver is electrically connected to the first electrode layer and the second electrode layer and is used for changing the voltage difference between the first electrode layer and the second electrode layer so as to switch the light beam between the structured light and the floodlight.

2. The adjustable light projector of claim 1 wherein the fixed optical phase modulator is configured to modulate the light beam into structured light or flood light.

3. The adjustable light projector of claim 1 wherein the fixed optical phase modulator is configured to modulate the light beam into collimated light.

4. The adjustable light projector of claim 1 wherein the patterned layer has a plurality of micro-apertures having a maximum diameter of less than 1 mm.

5. The adjustable light projector of claim 4, wherein the plurality of micro-apertures have a shape comprising a circle, a rectangle, a square, a hexagon, or a combination thereof.

6. The adjustable light projector of claim 4 wherein the plurality of micro-apertures are regular in size and location.

7. The adjustable light projector of claim 4 wherein the plurality of micro-apertures are irregular in size and location.

8. The adjustable light projector of claim 1 wherein the optical spatial phase distribution of the liquid crystal layer changes as the voltage difference changes to switch the light beam between the structured light and the flood light.

9. The adjustable light projector of claim 1 wherein the liquid crystal layer comprises nematic liquid crystals, polymer dispersed liquid crystals, or polymer network liquid crystals.

10. The adjustable light projector of claim 1 wherein the adjustable liquid crystal panel further comprises:

a first alignment layer disposed between the first substrate and the liquid crystal layer; and

the second alignment layer is configured between the second substrate and the liquid crystal layer.

11. The adjustable light projector of claim 10, wherein the first alignment layer and the second alignment layer are vertical alignment layers, horizontal alignment layers, or a combination thereof.

12. The adjustable light projector of claim 10, wherein the first alignment layer and the second alignment layer are aligned with a uniform spatial distribution.

13. The adjustable light projector of claim 10, wherein the first alignment layer and the second alignment layer are aligned with an irregular spatial distribution.

14. The adjustable light projector of claim 13 wherein the irregular spatially distributed local uniform alignment area is smaller than an area of a spot on the adjustable liquid crystal panel illuminated by the light beam from the fixed optical phase modulator.

15. The adjustable light projector of claim 1, further comprising a high-resistance layer adjacent to the patterned layer.

16. The adjustable light projector of claim 1, wherein the patterned layer comprises a plurality of conductive micropatterns.

17. The adjustable light projector of claim 16, wherein the plurality of conductive micropatterns have a rectilinear shape or a zig-zag shape.

18. The adjustable light projector of claim 1, wherein the first electrode layer and the second electrode layer have a lateral-field-switching or fringe-field-switching electrode design.

19. The adjustable light projector of claim 1, wherein the first electrode layer and the second electrode layer are two patterned layers respectively disposed on the first substrate and the second substrate, and the patterns of the two patterned layers are different from each other.

20. The adjustable light projector of claim 1, wherein the first electrode layer and the second electrode layer are two patterned layers respectively disposed on the first substrate and the second substrate, and the patterns of the two patterned layers are identical to each other.

Technical Field

The present invention relates to a sensing device and a light projector, and more particularly, to an optical sensing device, a structured light projector and an adjustable light projector.

Background

The mainstream technologies of three-dimensional sensing (3D sensing) are time of flight (TOF) and structured light (structured light) technologies. TOF technology uses pulsed lasers (pulsed lasers) and Complementary Metal Oxide Semiconductor (CMOS) sensors to measure light reflection time as a function of distance. Due to cost and structure, it is generally suitable for object analysis over long distances. In structured light technology, an Infrared (IR) source is projected onto a Diffractive Optical Element (DOE) to generate a two-dimensional diffraction pattern, and a sensor is used to collect the reflected light. The three-dimensional distance of the object can be converted by trigonometry. Structured light technology is limited to projection lenses with fixed focal lengths, and therefore the distance over which diffraction patterns can be imaged clearly is also limited, ultimately resulting in the distance over which objects can be resolved being limited to a small range.

To solve the above-mentioned problems of structured light technology, a system has been proposed in which an apodized lens (apodized lenses) is added to the lens group to generate multiple focal lengths. However, this approach sacrifices light efficiency and the number of dots and resolution of the two-dimensional diffraction pattern.

In addition, in the three-dimensional face recognition of the mobile device, both the floodlight system and the structured light system are adopted to achieve the three-dimensional face recognition. The floodlight system is first used to determine whether the approaching object is a human face, and if the approaching object is a human face, the structured light system is then activated and used to determine whether the detected human face is the face of the user of the mobile device. However, the use of two systems (i.e., a floodlight system and a structured light system) in a mobile device takes up much space and is expensive.

Disclosure of Invention

The invention provides an optical sensing device for controlling the focusing of structured light by using liquid crystal.

The invention provides a structured light projector that controls the focusing of structured light using liquid crystals.

The invention provides an adjustable light projector, which utilizes an adjustable liquid crystal panel to switch light beams between structured light and floodlight.

An embodiment of the present invention provides an optical sensing device, which is suitable for detecting an object or a characteristic of the object. The optical sensing device includes a structured light projector and a sensor. The structured light projector is used for projecting structured light to the object. The structured light projector includes a light source, a diffractive optical element, and a liquid crystal lens module. The light source is used for emitting light beams. The diffraction optical element is arranged on the path of the light beam and is used for generating a diffraction pattern to form structured light. The liquid crystal lens module is configured on at least one of the path of the light beam and the path of the structured light and can control the focusing between at least two focusing states. The sensor is adjacent to the structured light projector for sensing the reflected light. The reflected light is the reflection of structured light from an object.

Embodiments of the present invention provide a structured light projector. The structured light projector includes a light source, a diffractive optical element, and a liquid crystal lens module. The light source is used for emitting light beams. The diffraction optical element is arranged on the path of the light beam and is used for generating a diffraction pattern to form structured light. The liquid crystal lens module is configured on at least one of the path of the light beam and the path of the structured light and can control the focusing between at least two focusing states.

An embodiment of the invention provides an adjustable light projector, which includes a light source, a fixed optical phase modulator, an adjustable liquid crystal panel, and a driver. The light source is used for emitting light beams. The fixed optical phase modulator is configured on the path of the light beam and is used for modulating the phase of the light beam. The adjustable liquid crystal panel is configured on the path of the light beam and is used for switching the light beam between the structured light and the floodlight. The adjustable liquid crystal panel comprises a first substrate, a second substrate, a liquid crystal layer, a first electrode layer and a second electrode layer. The liquid crystal layer is arranged between the first substrate and the second substrate. At least one of the first electrode layer and the second electrode layer is a patterned layer. The first electrode layer and the second electrode layer are both arranged on one of the first substrate and the second substrate or are respectively arranged on the first substrate and the second substrate. The driver is electrically connected to the first electrode layer and the second electrode layer and used for changing the voltage difference between the first electrode layer and the second electrode layer, so that the light beam is switched between the structured light and the floodlight.

In view of the above, the structured light projector according to the embodiment of the invention includes at least one liquid crystal lens module with adjustable zoom. Providing a liquid crystal lens module with an adjustable zoom within a structured light projector increases the range over which the structured light can be focused. In addition, a small optical sensor using the structured light projector described above can be obtained. In the adjustable light projector according to the embodiment of the invention, the adjustable liquid crystal panel is used for switching the light beam between the structured light and the floodlight, so that the floodlight system and the structured light system are integrated into a single system according to the embodiment of the invention, which reduces the cost and volume of the electronic device with the structured light and the floodlight functions.

In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.

Drawings

FIG. 1 is a schematic diagram of an optical sensing device according to an embodiment of the invention.

Fig. 2 is a schematic cross-sectional view of the structured light projector of fig. 1.

Fig. 3A-3C are cross-sectional schematic views of another structured light projector according to at least one embodiment of the present disclosure.

Fig. 4A and 4B are schematic cross-sectional views of different liquid crystal lens modules of fig. 2 in two different states according to at least one embodiment of the invention.

Fig. 5 to 8 are schematic cross-sectional views of different liquid crystal lens modules of fig. 2 according to at least one embodiment of the invention.

FIG. 9 is a schematic top view of a liquid crystal layer according to at least one embodiment of the invention.

Fig. 10A to 10B are schematic cross-sectional views of another liquid crystal lens module according to at least one embodiment of the invention in two different states.

FIGS. 11A and 11B are schematic cross-sectional views of an adjustable light projector in a structured light mode and a flood mode, respectively, according to an embodiment of the invention.

Fig. 12A, 12B and 12C are schematic top views of the first electrode layer in fig. 11A and 11B, respectively, according to three embodiments of the present invention.

Fig. 13A, 13B and 13C are schematic top views of three other variations of the first electrode layer of fig. 12A.

FIG. 14A is a cross-sectional view of the tunable liquid crystal panel of FIG. 11A.

FIGS. 14B and 14C illustrate two other variations of the adjustable LCD panel of FIG. 14A.

FIG. 15A is a schematic cross-sectional view of an adjustable LCD panel according to another embodiment of the present invention.

FIG. 15B is a schematic cross-sectional view of an adjustable LCD panel according to another embodiment of the invention.

FIG. 15C is a schematic cross-sectional view of an adjustable LCD panel according to another embodiment of the present invention.

Fig. 16A illustrates alignment of the first alignment layer or the second alignment layer in fig. 15A or 15C according to an embodiment of the invention.

Fig. 16B illustrates another variation of alignment of the first alignment layer or the second alignment layer in fig. 15A or 15C according to another embodiment of the present invention.

FIG. 17A is a schematic cross-sectional view of an adjustable light projector using the alignment layer of FIG. 16B.

Fig. 17B is a schematic top view of the spot region and the alignment layer in fig. 17A.

FIGS. 18A, 18B and 18C are schematic cross-sectional views of the tunable liquid crystal panel and voltage differences applied to the liquid crystal layer in three different modes.

FIG. 19A is a schematic cross-sectional view of an adjustable LCD panel according to another embodiment of the present invention.

Fig. 19B is a schematic top view of the first substrate in fig. 19A.

FIG. 20A is a schematic cross-sectional view of an adjustable LCD panel according to another embodiment of the present invention.

Fig. 20B is a schematic top view of the first substrate in fig. 20A.

FIG. 21A is a schematic cross-sectional view of an adjustable LCD panel according to another embodiment of the invention.

FIG. 21B is a schematic cross-sectional view of an adjustable LCD panel according to another embodiment of the invention.

FIG. 22 is a cross-sectional view of an adjustable light projector according to another embodiment of the invention.

Description of the reference numerals

10: electronic device

102: object

100. 200a, 200b, 200 c: structured light projector

104: sensor device

106: opening of the container

110: light source

120. 220, 320, 420a, 420b, 520, 620, 720: liquid crystal lens module

122: liquid crystal lens unit

124: solid state lens

130: diffractive optical element

222: liquid crystal layer

224 a: first substrate

224 b: second substrate

226: liquid crystal molecules

228. 428a, 428 b: power supply

230 a: first electrode/electrode

230 b: second electrode/electrode

230 c: third electrode/electrode

232 a: alignment film/first alignment film

232 b: alignment film/second alignment film

530 a: electrode for electrochemical cell

530 b: floating electrode

640: high resistance material layer

722: liquid crystal cell

724: anisotropic lens

800. 800c, 800 k: adjustable light projector

810: light source

811: light beam

820: fixed optical phase modulator

830: driver

900. 900a, 900b, 900c, 900d, 900e, 900f, 900g, 900h, 900i, 900 j: adjustable liquid crystal panel

910: first substrate

920: second substrate

930. 930a, 930 b: liquid crystal layer

932. 932 b: liquid crystal molecules

934: polymer networks

934 b: polymer and method of making same

940. 940 g: a first electrode layer

942: micro-open pore

942g, 952 g: conductive micropattern

950. 950g, 950h, 950 j: a second electrode layer

960. 960a, 960 d: a first alignment layer

970. 970a, 970 d: second alignment layer

980: high resistance layer

990: insulating layer

A1: optical axis

D: maximum diameter

F1, F2: focal length

L1: alignment

LB: light beam

And (3) LP: polarized light

R1: local same alignment region

R2: light spot area

SL: structured light

Δ V: voltage difference

Detailed Description

The exemplary embodiments will be described in detail below with reference to the drawings, wherein like reference numerals and descriptions are used to refer to the same or equivalent elements.

In addition, spatially relative terms such as "under", "lower", "over", "up", "top", "bottom", "left", "right", and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures, for ease of description. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly as well.

Fig. 1 is a schematic diagram of an optical sensing device 10 according to an embodiment of the invention. The optical sensing device 10 shown in fig. 1 is a sensing device for detecting an object by using structured light. Specifically, the optical sensing device 10 includes a structured light projector 100 and a sensor 104 adjacent to the structured light projector 100. The structured light projector 100 is configured to generate structured light SL toward the object 102, and the sensor 104 is configured to sense the structured light SL reflected from the object 102. Structured light SL may include, but is not limited to, multiple beams that project light patterns onto object 102, such as: a series of lines, loops, dots, or the like. Wherein the lines, loops, dots, or the like may be ordered or unordered. The object 102 may be, for example, a palm of a hand, a human face, or any object having three-dimensional features. When the structured light SL is projected onto the object 102, the light pattern of the structured light SL may be deformed due to the concave-convex surface of the object 102. The deformed structured light SL is then reflected from the object 102, and the reflected light passes through the opening 106 to the sensor 104. For example, the opening 106 may include a lens, a hole, a transparent cover, and the like. The sensor 104 senses the deformation of the light pattern on the object 102 to calculate the depth of the surface of the object 102, i.e., the distance between a point on the surface of the object 102 and the sensor 104. The sensor 104 may be connected to a processor (not shown) for calculating three-dimensional features of the object 102.

FIG. 2 is a cross-sectional schematic view of a structured light projector 100 according to an embodiment of the present invention. The structured light projector 100 includes a light source 110, a liquid crystal lens module 120, and a Diffractive Optical Element (DOE) 130. The light source 110 disposed at one end of the structured light projector 100 is used for emitting a light beam LB. The light source 110 may be a Light Emitting Diode (LED), a laser diode, an edge emitting laser (edge emitting laser), a vertical-cavity surface-emitting laser (VCSEL), or any other light source capable of emitting a visible or invisible (e.g., Infrared (IR) or Ultraviolet (UV)) light beam LB. In some embodiments, the light source 110 may be a single IR laser diode, and in other embodiments, the light source 110 may be an IR laser diode array, and the number of light sources forming the light source 110 is not limited thereto.

The structured light projector 100 further includes a liquid crystal lens module 120 disposed in the path of the light beam LB. The lc lens module 120 can control the in-focus state of the light beam LB to provide at least two in-focus states for the structured light projector 100. A polarizer (not shown) may optionally be placed on the beam LB in front of the lc lens module 120 to provide the polarized beam LB to the lc lens module 120.

As shown in fig. 2, diffractive optical element 130 is disposed on the path of light beam LB and behind liquid crystal lens module 120. However, the arrangement order of the diffractive optical element 130 and the liquid crystal lens module 120 is not limited thereto. In some embodiments, diffractive optical element 130 can be disposed in the path of light beam LB and before liquid crystal lens module 120. In some embodiments, it may even be placed in the path of the light beam LB and between the various components of the LC lens module 120. Diffractive optical element 130 is an optical element for generating a diffraction pattern for generating structured light SL as described above with reference to FIG. 1. For example, diffractive optical element 130 can include a pattern that splits beam LB to multiple spots, or shapes beam LB to grid lines, but is not limited to such. For simplicity, the light beam LB passing through the diffractive optical element 130 is hereinafter referred to as structured light SL. Furthermore, for ease of description, the x-direction and the z-direction are provided perpendicular to each other. For example, in the present embodiment, the z-direction is defined as a direction perpendicular to the surface from which the light source 110 emits light.

Fig. 3A-3C show schematic cross-sectional views of various structured light projectors 200 a-200C according to some embodiments of the present invention. The structured light projectors 200 a-200 c are similar to the structured light projector 100 shown in fig. 2. The difference between the structured light projectors 200 a-200 c and the structured light projector 100 is that the structured light projectors 200 a-200 c include the liquid crystal lens unit 122 and the solid lens 124 without the liquid crystal lens module 120. In some embodiments, the combination of the lc lens cell 122 and the solid lens 124 may be used as the lc lens module 120 of fig. 2.

Referring to fig. 3A, the solid lens 124 is disposed on the path of the light beam LB and between the diffractive optical element 130 and the light source 110, and the liquid crystal lens unit 122 is disposed on the path of the light beam LB and between the solid lens 124 and the diffractive optical element 130. In fig. 3B, solid lens 124 is disposed on the path of light beam LB and between diffractive optical element 130 and light source 110, and liquid crystal lens unit 122 is disposed on the side of diffractive optical element 130 away from light source 110. In other words, the lc lens unit 122 is disposed on the path of the structured light SL. In fig. 3C, the solid lens 124 is disposed on the path of the light beam LB and between the diffractive optical element 130 and the light source 110, and the liquid crystal lens unit 122 is disposed on the path of the light beam LB and between the solid lens 124 and the light source 110.

In some embodiments, the solid lens 124 may be a single lens or a combination with multiple lenses that define the primary focal length of the structured light projector 200 a. In some embodiments, solid lens 124 collimates light beam LB before it enters liquid crystal lens unit 122 or diffractive optical element 130. In some embodiments, the lc lens cell 122 has an adjustable focal length and includes at least one liquid crystal cladding (liquid crystal cell layer). The focal length of the lc lens cell 122 may be controlled by applying a voltage to control the orientation of liquid crystal molecules (not shown) within the lc lens cell 122.

Fig. 4A-8 disclose some embodiments of a liquid crystal lens module that can be used as the liquid crystal lens module 120 of fig. 2. In some embodiments, the liquid crystal lens module disclosed in fig. 4A to 8 can be used as the liquid crystal lens unit 122 of fig. 3A to 3C, and the invention is not limited thereto.

Fig. 4A and 4B are schematic cross-sectional views of a liquid crystal lens module 220 according to an embodiment of the invention. The liquid crystal lens module 220 includes a first substrate 224a, a second substrate 224b and a liquid crystal layer 222. The liquid crystal layer 222 is sandwiched between a first substrate 224a and a second substrate 224b in the vertical direction (z-direction). The effective refractive index of each portion of the liquid crystal layer 222 is related to the voltage applied to the first electrode 230a and the second electrode 230b, wherein the first electrode 230a is disposed on the first substrate 224a between the liquid crystal layer 222 and the first substrate 224a, the second electrode 230b is disposed on the second substrate 224b between the liquid crystal layer 222 and the second substrate 224b, and the voltage is provided by the power source 228. The liquid crystal lens module 220 further includes alignment films 232 disposed on the first electrode 230a and the second electrode 230b respectively and contacting opposite sides of the liquid crystal layer 222. The alignment films 232a and 232b have surface textures for providing initial alignment of the liquid crystal molecules 226 by controlling the pretilt angle and the polar angle of the liquid crystal molecules 226. The pretilt angle refers to an angle between a long axis of the liquid crystal molecules 226 and a plane perpendicular to the z-direction; the polar angle refers to the angle between the long axis of the liquid crystal molecules 226 and a fixed axis (e.g., along the x-direction) on a plane perpendicular to the z-direction. The material for the alignment layer 232 of the present embodiment can be a polymer (e.g., polyimide), but is not limited thereto.

Referring to fig. 4A, the liquid crystal layer 222 of the liquid crystal lens module 220 has a non-uniform thickness. As shown in fig. 4A, the liquid crystal layer 222 has a curved surface and a flat surface, and is thickest in the middle. The curved surface of the liquid crystal layer 222 corresponds to the curved surface of the first substrate 224a, the curved first electrode 230a, and the curved upper alignment film 232 a. In addition, in the present embodiment, when the electrodes 230a and 230b are disconnected from the power source 228, all the liquid crystal molecules 226 in the liquid crystal layer 222 are aligned with substantially the same orientation. That is, the long axes of all the liquid crystal molecules 226 are along the horizontal x-direction, where the x-direction is orthogonal to the z-direction. When the electrodes 230a and 230B are turned on with the power 228, as shown in FIG. 4B, the orientation of the liquid crystal molecules 226 is rotated to align the long axis and the z-direction.

In the present embodiment, the liquid crystal lens module 220 shown in fig. 4A to 4B can be used as a refractive lens (reactive lens). Specifically, when the LC lens module 220 is not connected to the power supply 228, the liquid crystal layer 222 has a first effective refractive index such that when combined with the convex shape of the LC lens module 220, light entering along the z-direction is focused to a first focal length F1. In FIG. 4B, when the liquid crystal lens module 220 is connected to the power supply 228, the alignment of the liquid crystal molecules 226 along the z-axis changes the effective refractive index of the liquid crystal layer 222 to a second effective refractive index, such that when combined with the convex shape of the liquid crystal layer 222, light entering along the z-direction is focused to a second focal length F2. Therefore, the focal length of the lc lens module 220 can be controlled by turning on or off the power 228.

FIG. 5 is a cross-sectional view of an exemplary liquid crystal lens module 320 according to an embodiment of the invention. The liquid crystal lens module 320 includes a first substrate 224a, a second substrate 224b, a liquid crystal layer 222, a first electrode 230a, a second electrode 230b, and alignment films 232a and 232b, which are arranged similarly to the liquid crystal lens module 220. Referring to fig. 5, the difference between the lc lens module 320 and the lc lens module 220 is the shapes of the first substrate 224a, the first electrode 230a, the second electrode 230b, and the first alignment film 232 a. Specifically, in fig. 5, the first substrate 224a is a substrate having a uniform thickness in the z-direction, the first electrode 230a and the first alignment film 232a are flat, and the second electrode 230b and the second alignment film 232b are stepped. Based on the step shape of the second electrode 230b and the second alignment film 232b, the liquid crystal layer 222 has a liquid crystal layer with a non-uniform thickness and optical characteristics of a diffractive lens. For example, the step shape of the second electrode 230b and the second alignment film 232b may be designed such that the liquid crystal layer 222 following the step shape may be a Fresnel lens (Fresnel lens), but the present invention is not limited thereto. Similar to the liquid crystal lens module 220, the focal length of the liquid crystal lens module 320 may be controlled by applying a voltage between the first electrode 230a and the second electrode 230 b.

FIG. 6A is a schematic cross-sectional view of a liquid crystal lens module 420a according to an embodiment of the invention.

In fig. 6A, the lc lens module 420a includes a first substrate 224a, a second substrate 224b, a liquid crystal layer 222, a second electrode 230b, and alignment films 232a and 232b, which are arranged similarly to the lc lens module 220. Referring to fig. 6A, the differences between the lc lens module 420a and the lc lens module 220 are the first substrate 224a, the first electrode 230a, and the first alignment film 232 a. Specifically, in fig. 6A, the first substrate 224a is a substrate having a uniform thickness in the z-direction, the first electrode 230a is a patterned electrode having a gap or opening therebetween and disposed on a side of the first substrate 224a opposite to the liquid crystal layer 222, and the first alignment film 232a is flat. Therefore, the liquid crystal layer 222 of the present embodiment has a uniform thickness. In some embodiments, the first electrode 230a may also be disposed between the first substrate 224a and the first alignment film 232a, but is not limited thereto.

Based on the pattern of the first electrodes 230a, the voltage in the liquid crystal layer 222 is unevenly distributed, resulting in the liquid crystal molecules 226 having a different orientation when the first electrodes 230a are connected to a power source. In some embodiments, the pattern of the first electrode 230a may be any other pattern than the pattern shown in fig. 6A. The non-uniform distribution of liquid crystal orientation produces a distributed index of refraction. The liquid crystal lens module 420a may be a refractive lens or a diffractive lens depending on the refractive index distribution.

FIG. 6B is a schematic cross-sectional view of a liquid crystal lens module 420B according to an embodiment of the invention. The lc lens module 420b is similar to the lc lens module 420a except that the lc lens module 420b further includes a third electrode 230 c. The third electrode 230c is adjacent to the first electrode 230a and away from the liquid crystal layer 222. In this embodiment, the first and second electrodes 230a and 230b may be connected to a first power supply 428a to provide a voltage V1, and the third and second electrodes 230c and 230b may be connected to a second power supply 428b to provide a voltage V2. The addition of the third electrode 230c allows further control of the voltage distribution in the liquid crystal layer 222 to provide further fine tuning of the optical properties. The liquid crystal lens module 420b may be a refractive lens or a diffractive lens depending on the refractive index distribution.

FIG. 7 is a cross-sectional view of an exemplary liquid crystal lens module 520 according to the present invention. The liquid crystal lens module 520 is a liquid crystal lens module having a liquid crystal layer 222 with a uniform thickness. Specifically, the liquid crystal lens module 520 includes first and second substrates 224a and 224b, a liquid crystal layer 222, a second electrode 230b, and alignment films 232a and 232b, which are arranged similarly to the liquid crystal lens module 420 a. The difference between the liquid crystal lens module 520 and the liquid crystal lens module 420a is the position of the first electrode 230a and the structure of the second electrode 230 b. Specifically, in fig. 7, the first electrode 230a is disposed between the first substrate 224a and the first alignment film 232a, and the second electrode 230b is a pixelated electrode. The second electrode 230b includes at least one electrode 530a connected to the power source 228 and at least one floating electrode 530b disposed adjacent to the electrode 530a to form a pixelated structure. The floating electrode 530b is separated by an insulator disposed therebetween, for example, by a portion of the first alignment film 232b, as shown in fig. 7. In some embodiments, the floating electrode 530b may also be disposed on the first substrate 230a, the second substrate 230b, or both the first substrate 230a and the second substrate 230 b. The voltage on the floating electrode 530b of the second electrode 230b is related to the adjacent electrode 530 a. The floating electrode 530b provides more voltage variation pitch to better control the orientation of the liquid crystal molecules in the liquid crystal layer 222. Alternatively, some or all of the floating electrodes 530b may be individually connected to other power sources to further control the liquid crystal molecules. Depending on the refractive index profile, the liquid crystal lens module 520 may be a refractive lens or a diffractive lens.

FIG. 8 is a cross-sectional view of an exemplary liquid crystal lens module 620 according to the present invention. The liquid crystal lens module 620 is similar to the liquid crystal lens module 520 except that the liquid crystal lens module 620 has a pixelated first electrode 230a and further includes a high-resistance material layer 640 disposed between the pixelated first electrode 230a and the first alignment film 232 a. The high-resistance material layer 640 provides a continuously varying voltage between the electrodes, thereby improving the quality of the formed image. The sheet resistance of the high-resistance material layer 640 is in the range of 10⁹To 10¹⁴Ohm per square (Ω/sq). For example, the high-resistance material layer 640 is made of a semiconductor material including a group III-V semiconductor compound or a group II-VI semiconductor compound or a polymer material including poly (3,4-ethylenedioxythiophene) ((PEDOT))). Of course, the high-resistance material layer 640 may be implemented in any of the liquid crystal lens modules described above, and may have any other pattern. The present invention is not limited thereto.

FIG. 9 is a schematic top view (i.e., along the z-direction) of a liquid crystal layer 222 according to an embodiment of the invention. Specifically, fig. 9 is an exemplary arrangement pattern of liquid crystal molecules in the liquid crystal layer 222 on the x-y plane due to the control of the alignment film. The y-direction provided in fig. 9 is perpendicular to the x and z directions. As shown in fig. 9, the polar angle of the liquid crystal molecules is controlled by the alignment film to form a Pancharatnam-Berry phase liquid crystal lens. Other liquid crystal lenses may be formed by alignment films having different surface patterns, to which the present invention is not limited.

Fig. 10A and 10B are schematic cross-sectional views of a liquid crystal lens module 720 according to an embodiment of the invention. In fig. 10A and 10B, the liquid crystal lens module 720 includes a liquid crystal cell 722 and an anisotropic lens (anisotropic lens)724, wherein the liquid crystal cell 722 is connected to the power supply 228. In the liquid crystal lens module 720, the liquid crystal cell 722 is disposed on a path of light polarized in the directions perpendicular to the x and z directions (polarized light LP as shown in fig. 10A). The liquid crystal cell 722 is configured to control the polarization of incident light.

Referring to fig. 10A and 10B, when the liquid crystal cell 722 is in an off state (no voltage applied), the polarization of incident light is not affected, and when the liquid crystal cell 722 is in an on state (voltage applied), the polarization of incident light is rotated by 90 degrees to the x-direction. In other words, when liquid crystal cell 722 is turned on, the liquid crystal cell acts as a half-wave plate to change the polarization of incident light. The anisotropic lens 724 is disposed on an optical path passing through the liquid crystal cell 722. The refractive index (i.e., focal length) of the anisotropic lens 724 depends on the polarization of the light, e.g., the refractive index is greatest when the light is polarized in the direction of the optical axis a1 of the anisotropic lens and the refractive index is smallest when the polarization of the light is orthogonal to the optical axis a 1. Since the turning on and off of the liquid crystal cell 722 changes the polarization of light, the focal length of the anisotropic lens also changes. The liquid crystal lens module 720 is also referred to as a passive liquid crystal lens because the liquid crystal cell does not actively focus or disperse light.

The voltage distributions applied to the electrodes of the liquid crystal lens module, the liquid crystal lens cell, and the liquid crystal cell as described above may be controlled by a controller coupled to the electrodes. In some embodiments, the controller is, for example, a Central Processing Unit (CPU), a microprocessor, a Digital Signal Processor (DSP), a programmable controller, a Programmable Logic Device (PLD), or the like, or a combination thereof, and is not particularly limited by the present invention. Further, in some embodiments, each function of the controller may be implemented in multiple program codes. The program code will be stored in memory or a non-transitory storage medium so that the program code can be executed by the controller. Alternatively, in one embodiment, each function of the controller may be implemented in one or more circuits. The present invention is not intended to limit whether each function of the controller is implemented by software or hardware.

By providing a liquid crystal lens with an adjustable focal length in the structured light projector, the focus range of the structured light projector becomes adjustable and can cover a wider range, enabling measurement of features at different distances on the 3D object. In addition, the optical projector using the liquid crystal lens has advantages of smaller size and low power consumption compared to a conventional Voice Coil Motor (VCM) in the focus lens. Thus, the optical projector of the present invention can be easily installed in a mobile electronic device, providing the mobile electronic device with 3D sensing features.

FIGS. 11A and 11B are schematic cross-sectional views of an adjustable light projector in a structured light mode and a flood mode, respectively, according to an embodiment of the invention. Referring to fig. 11A and 11B, the adjustable light projector 800 of the present embodiment includes at least one light source 810 (in fig. 11A and 11B, a plurality of light sources 810 are taken as an example), an adjustable liquid crystal panel 900 with a fixed optical phase modulator 820, and a driver 830. The light sources 810 are configured to emit a plurality of light beams 811 (fig. 11A and 11B schematically illustrate an example where one light source 810 emits one light beam 811). In the present embodiment, the light sources 810 are a plurality of light emitting areas (or light emitting points) of a vertical cavity surface emitting laser, or a plurality of edge-emitting lasers (EEL), or a plurality of other suitable laser emitters or laser diodes, respectively.

The fixed optical phase modulator 820 is disposed on the path of the light beam 811, and modulates the phase of the light beam 811. In the present embodiment, the fixed optical phase modulator 820 is, for example, a diffractive optical element or a lens array, and modulates the light beam 811 into a structured light.

The adjustable liquid crystal panel 900 is disposed in the path of the light beam 811, and is used for switching the light beam 811 between the structured light (as shown in fig. 11A) and the flood light (as shown in fig. 11B). In the present embodiment, the tunable liquid crystal panel 900 is disposed on the path of the light beam 811 from the fixed optical phase modulator 820. The tunable liquid crystal panel 900 includes a first substrate 910, a second substrate 920, a liquid crystal layer 930, a first electrode layer 940, and a second electrode layer 950. The liquid crystal layer 930 is disposed between the first substrate 210 and the second substrate 920. At least one of the first electrode layer 940 and the second electrode layer 950 is a patterned layer. Fig. 11A and 11B illustrate the first electrode layer 940 as a patterned layer. However, in other embodiments, the second electrode layer 950 may be a patterned layer, or both the first electrode layer 940 and the second electrode layer 950 may be patterned layers. In the present embodiment, the first substrate 910 and the second substrate 920 are transparent substrates, such as glass substrates or plastic substrates. The first electrode layer 940 and the second electrode layer 950 may be made of Indium Tin Oxide (ITO), other conductive metal oxides, or other transparent conductive materials.

The first electrode layer 940 and the second electrode layer 950 are disposed on one of the first substrate 910 and the second substrate 920, or disposed on the first substrate 910 and the second substrate 920, respectively. The driver 830 is electrically connected to the first electrode layer 940 and the second electrode layer 950, and is used for changing a voltage difference between the first electrode layer 940 and the second electrode layer 950, so as to switch the light beam 811 between the structured light and the flood light. Specifically, the optical spatial phase distribution of the liquid crystal layer 930 changes with the change of the voltage difference, so that the light beam 811 is switched between the structured light and the flood light.

For example, in FIG. 11A, the voltage difference between the first electrode layer 940 and the second electrode layer 950 is about zero, and the refractive index profile of the liquid crystal layer 930 is uniform, so the liquid crystal layer 930 resembles a transparent layer. Therefore, the structured light from the fixed optical phase modulator 820 passes through the transparent layer and remains structured light, and the adjustable light projector 800 is in the structured light mode. In FIG. 11B, the voltage difference between the first electrode layer 940 and the second electrode layer 950 is not equal to zero, and the refractive index distribution of the liquid crystal layer 930 is non-uniform, so the liquid crystal layer 930 resembles a lens array. Therefore, the structured light from the fixed optical phase modulator 820 is converted into flood light by this lens array, and the adjustable light projector 800 is in flood mode. The structured light may be illuminated on the object to form a light pattern on the object having a plurality of dots, having stripes, or having other suitable patterns. The floodlight can uniformly irradiate an object.

In the adjustable light projector of the present embodiment, the adjustable liquid crystal panel 900 is used to switch the light beam 811 between the structured light and the flood light, so the present embodiment integrates the flood light system and the structured light system into a single system, which reduces the cost and volume of the electronic device with the structured light and the flood light functions.

In another embodiment, a fixed optical phase modulator 820 is used to modulate the light beam 811 into flood light. Furthermore, when the voltage difference between the first electrode layer 940 and the second electrode layer 950 is about zero, the flood light from the fixed optical phase modulator 820 penetrates the liquid crystal layer 930 (which is now a transparent layer) and remains flood light. When the voltage difference between the first electrode layer 940 and the second electrode layer 950 is not zero, the flood light from the fixed optical phase modulator 820 is converted into structured light by the liquid crystal layer 930 (which is now a lens array-like optical layer).

In another embodiment, the fixed optical phase modulator 820 is used to modulate the light beam into collimated light, and two voltage differences between the first electrode layer 940 and the second electrode layer 950 respectively switch the liquid crystal layer 930 to two refractive index distributions, thereby respectively switching the collimated light from the fixed optical phase modulator 820 into structured light and flood light.

Fig. 12A, 12B and 12C are schematic top views of the first electrode layer in fig. 11A and 11B, respectively, according to three embodiments of the present invention. Referring to fig. 12A, 12B and 12C, a patterned layer (such as the first electrode layer 940 or the second electrode layer 950, and the first electrode layer 940 is shown as an example) has a plurality of micro-openings 942 having a maximum diameter D less than 1 mm. The shape of the micro-openings 942 includes circular (as shown in fig. 12A), rectangular (as shown in fig. 12B), square, hexagonal (as shown in fig. 12C), other geometric shapes, other irregular shapes, or combinations thereof.

Fig. 13A, 13B and 13C are schematic top views of three other variations of the first electrode layer of fig. 12A. Referring to fig. 12A, 13B and 13C, the size and position of the micro-holes 942 may be regular or irregular. For example, in fig. 12A, the sizes of the micro-openings 942 are equal to each other, and the positions of the micro-openings 942 are regular. In fig. 13A, the sizes of the micro-apertures 942 are equal to each other, and the positions of the micro-apertures 942 are irregular. In fig. 13B, the micro-apertures 942 have different sizes, and the locations of the micro-apertures 942 are regular. In fig. 13C, the micro-apertures 942 have different sizes, and the locations of the micro-apertures 942 are irregular.

FIG. 14A is a schematic cross-sectional view of the tunable liquid crystal panel shown in FIG. 11A, and FIGS. 14B and 14C show two other variations of the tunable liquid crystal panel shown in FIG. 14A. Referring to fig. 14A, the tunable liquid crystal panel 900 has a liquid crystal layer 930 including a Polymer Network Liquid Crystal (PNLC) including liquid crystal molecules 932 and a polymer network 934. Referring to FIG. 14B, the tunable liquid crystal panel 900a may have a liquid crystal layer 930a including a nematic liquid crystal (nematic liquid crystal). Referring to FIG. 14C, the tunable liquid crystal panel 900b may have a liquid crystal layer 930b including a Polymer Dispersed Liquid Crystal (PDLC) including liquid crystal molecules 932b and a polymer 934 b.

FIG. 15A is a schematic cross-sectional view of an adjustable LCD panel according to another embodiment of the present invention. Referring to fig. 15A, the tunable liquid crystal panel 900c of the present embodiment is similar to the tunable liquid crystal panel 900a of fig. 14B, and the main differences are as follows. In the present embodiment, the tunable liquid crystal panel 900c further includes a first alignment layer 960 and a second alignment layer 970. The first alignment layer 960 is disposed between the first substrate 910 and the liquid crystal layer 930a, and the second alignment layer 970 is disposed between the second substrate 920 and the liquid crystal layer 930 a. In the present embodiment, the first alignment layer 960 is disposed between the first electrode layer 940 and the liquid crystal layer 930a, and the second alignment layer 970 is disposed between the second electrode layer 950 and the liquid crystal layer 930 a. In the present embodiment, the first alignment layer 960 and the second alignment layer 970 are horizontal alignment layers (parallel alignment layers).

FIG. 15B is a schematic cross-sectional view of an adjustable LCD panel according to another embodiment of the invention. Referring to fig. 15B, the tunable liquid crystal panel 900d of the present embodiment is similar to the tunable liquid crystal panel 900c, and the main differences are as follows. In the tunable liquid crystal panel 900d of the present embodiment, the first alignment layer 960d and the second alignment layer 970d are vertical alignment layers (vertical alignment layers).

FIG. 15C is a schematic cross-sectional view of an adjustable LCD panel according to another embodiment of the present invention. Referring to fig. 15C, the tunable liquid crystal panel 900e of the present embodiment is similar to the tunable liquid crystal panel 900C, and the main differences are as follows. In the tunable liquid crystal panel 900e of the present embodiment, the first alignment layer 960 and the second alignment layer 970d are a combination of a vertical alignment layer and a horizontal alignment layer. For example, the first alignment layer 960 is a horizontal alignment layer, and the second alignment layer 970d is a vertical alignment layer.

Fig. 16A illustrates alignment (alignment direction) of the first alignment layer or the second alignment layer in fig. 15A or 15C according to an embodiment of the invention. Referring to fig. 16A, in an embodiment, the alignment L1 of the first alignment layer 960 and the second alignment layer 970 have a uniform spatial distribution. In other words, the azimuthal angles (azimuthal angles) of the alignments in different regions of the first alignment layer 960 or the second alignment layer 970 are the same as each other.

Fig. 16B illustrates another variation of alignment of the first alignment layer or the second alignment layer in fig. 15A or 15C according to another embodiment of the present invention. Referring to fig. 16B, in another embodiment, the alignment L1 of the first alignment layer 960a and the second alignment layer 970a has an irregular spatial distribution. In other words, the azimuthal angles of the alignments in different regions of first alignment layer 960a or second alignment layer 970a are different from each other. Different orientations and different azimuths can reflect or diffract light 811 from the light source 810 with different polarization directions.

FIG. 17A is a schematic cross-sectional view of an adjustable light projector using the alignment layer of FIG. 16B. Fig. 17B is a schematic top view of the spot region and the alignment layer in fig. 17A. Referring to fig. 17A and 17B, the adjustable light projector 800c of the present embodiment is similar to the adjustable light projector 800 of fig. 11A, and the main differences are as follows. In the tunable light projector 800c of the present embodiment, the local identical alignment region R1 of the irregular spatial distribution of the alignment of the first alignment layer 960a and the second alignment layer 970a is smaller than the spot region R2 on the tunable liquid crystal panel 900c illuminated by the light beam 811 from the fixed optical phase modulator 820. Therefore, the light beams 811 with various polarization directions can be refracted or diffracted by the liquid crystal layer 900 c.

FIGS. 18A, 18B and 18C are schematic cross-sectional views of a tunable liquid crystal panel and voltage differences applied to the liquid crystal layer in three different modes. Referring to fig. 18A, 18B and 18C, the adjustable lcd panel 900f of the present embodiment is similar to the adjustable lcd panel 900B of fig. 14C, and the main differences are as follows. The tunable liquid crystal panel 900f of the present embodiment further includes a high-resistance layer 980 (same as the high-resistance material layer 640 of fig. 8) adjacent to the patterned layer (e.g., the first electrode layer 940). In FIG. 18A, when the voltage difference between the first electrode layer 940 and the second electrode layer 950 is zero, the voltage difference Δ V applied to the liquid crystal layer 930b is zero, and the liquid crystal layer 930b is in a scattering mode and is used to scatter the light beams 811 from the fixed optical phase modulator 820.

In 18B, when the voltage difference between the first electrode layer 940 and the second electrode layer 950 is an ac voltage of a high frequency (such "high frequency" is a frequency greater than 1kHz and equal to or less than 60kHz, for example), the voltage difference Δ V applied to the liquid crystal layer 930 gradually changes with position due to the high-resistance layer 930, and the liquid crystal layer 930B is in a scattering and condensing mode and is used to slightly scatter and condense the light beams 811 from the fixed optical phase modulator 820.

In 18C, when the voltage difference between the first electrode layer 940 and the second electrode layer 950 is an ac voltage of a low frequency (this "low frequency" is, for example, a frequency of 60Hz or more and 1kHz or less), the voltage difference Δ V applied to the liquid crystal layer 930 is approximately constant at different positions, the liquid crystal layer 930b is in a transparent mode and resembles a transparent layer, and the light beam 811 penetrates the liquid crystal layer 930 b. Further, the "high frequency" is larger than the "low frequency".

FIG. 19A is a schematic cross-sectional view of an adjustable LCD panel according to another embodiment of the invention, and FIG. 19B is a schematic top view of the first substrate shown in FIG. 19A. Referring to fig. 19A and 19B, the tunable liquid crystal panel 900g of the present embodiment is similar to the tunable liquid crystal panel 900c of fig. 15A, and the main differences are as follows. In the tunable liquid crystal panel 900g of the present embodiment, both the first electrode layer 940g and the second electrode layer 950g are disposed on the same substrate (e.g., the first substrate 910) and are patterned layers. The first electrode layer 940g and the second electrode layer 950g have an in-plane switch (IPS) electrode design. Specifically, the first electrode layer 940g includes a plurality of conductive micropatterns 942g, and the second electrode layer 950g includes a plurality of conductive micropatterns 952 g. The conductive micro patterns 942g and 952g are alternately arranged along a direction (e.g., the right direction in fig. 19A and 19B). The conductive micropattern 942g and the conductive micropattern 952g may have a linear shape. For example, each of the conductive micropattern 942g and the conductive micropattern 952g may extend in a direction perpendicular to the plane of the drawing of fig. 19A. However, in the present embodiment, the conductive micro-patterns 942g and 952g may have zigzag shapes as shown in fig. 19B.

FIG. 20A is a cross-sectional view of an adjustable LCD panel according to another embodiment of the invention, and FIG. 20B is a top view of the first substrate shown in FIG. 20A. The adjustable LCD panel 900h of the present embodiment is similar to the adjustable LCD panel 900g of FIG. 19A, and the main differences are as follows. In the tunable liquid crystal panel 900h of the present embodiment, the first electrode layer 940g and the second electrode layer 950h have fringe-field switch (FFS) electrode designs. The second electrode layer 950h is a flat continuous layer between the first electrode layer 940g and the first substrate 910, and the first electrode layer 940g and the second electrode layer 950 are insulated from each other by the insulating layer 990 disposed therebetween. The first electrode layer 940g in fig. 20A and 20B is identical to the description of the first electrode layer 940g in fig. 19A and 19B.

FIG. 21A is a schematic cross-sectional view of an adjustable LCD panel according to another embodiment of the invention. Referring to fig. 21A, the tunable liquid crystal panel 900j of the present embodiment is similar to the tunable liquid crystal panel 900a of fig. 14B, and the main differences are as follows. In the tunable liquid crystal panel 900j, the first electrode layer 940 and the second electrode layer 950j are two patterned layers respectively disposed on the first substrate 910 and the second substrate 920, and the patterns of the two patterned layers are the same. However, in other embodiments, the patterns of the two patterned layers may be different from each other.

FIG. 21B is a schematic cross-sectional view of an adjustable LCD panel according to another embodiment of the invention. Referring to fig. 21B, the tunable liquid crystal panel 900i of the present embodiment is similar to the tunable liquid crystal panel 900g or 900h of fig. 19A or 20A, and the main differences are as follows. The tunable liquid crystal panel 900i of the present embodiment includes a first electrode layer 940g and a second electrode layer 950g disposed on the first substrate 910 as shown in fig. 19A, and includes a first electrode layer 940g and a second electrode layer 950 as shown in fig. 20A disposed on the second substrate 920. That is, the first substrate 910 side has a lateral electric field switched electrode design, and the second substrate 920 side has a fringe field switched electrode design. However, in other embodiments, the first substrate 910 side and the second substrate 920 side may both have a lateral electric field switched electrode design, or the first substrate 210 side and the second substrate 920 side may both have a fringe field switched electrode design.

FIG. 22 is a cross-sectional view of an adjustable light projector according to another embodiment of the invention. The adjustable light projector 800k of the present embodiment is similar to the adjustable light projector 800 of fig. 11A and 11B, and the difference between the two is the arrangement order of the fixed optical phase modulator 820 and the adjustable liquid crystal panel 900. In fig. 11A and 11B, the fixed optical phase modulator 820 is disposed between the light source 810 and the adjustable liquid crystal panel 900. However, in the present embodiment, the tunable liquid crystal panel 200 is disposed between the light source 810 and the fixed optical phase modulator 820, that is, the fixed optical phase modulator 820 is disposed on the path of the light beam from the tunable liquid crystal panel 200, so that when the tunable liquid crystal panel 900 is switched between the different modes as in the previous embodiments, the light beam passing through the fixed optical phase modulator 820 can still be switched between the structured light and the flood light.

In summary, in the adjustable light projector according to the embodiment of the invention, the adjustable liquid crystal panel is used to switch the light beam between the structured light and the flood light, so the embodiment of the invention integrates the flood light system and the structured light system into a single system, which reduces the cost and volume of the electronic device with the structured light and the flood light functions. Each of the adjustable light projectors can replace any one of the structural light projectors in the optical sensing device to form an optical sensing device with both flood light recognition function and structural light recognition function. In the floodlight identification function, the sensor can sense an object and judge whether the object is a human face. In the structured light recognition function, the sensor can sense the light pattern on the object and determine whether the detected face is the face of the user of the electronic device.

Although the present invention has been described with reference to the above embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention.