Camera Module

Abstract

Provided is a camera module comprising a liquid crystal panel having a high transmittance.　A camera module according to one embodiment of the present invention comprises: a liquid crystal panel for displaying a coded aperture pattern; an imaging element; and an optical system disposed between the liquid crystal panel and the imaging element. The liquid crystal panel has a liquid crystal layer containing a polymer and liquid crystal molecules.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present invention relates to a camera module. [Background technology]

[0002] In recent years, camera modules have been developed that include a liquid crystal panel, an imaging element disposed on the rear surface of the liquid crystal panel, and an optical system disposed between the liquid crystal panel and the imaging element.

[0003] In such camera modules, coded aperture technology is known that utilizes the blur that occurs in an image generated based on light incident on an imaging element to calculate the distance from the camera module to a subject in the image.

[0004] However, since such a camera module functions as a normal camera except when calculating the distance to the subject as described above, it is desirable for the liquid crystal panel to have a high transmittance from the standpoint of the amount of light that can be incident on the imaging element. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 03-042621 [Patent Document 2] Patent No. 6428977 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a camera module equipped with a liquid crystal panel with high transmittance. [Means for solving the problem]

[0007] A camera module according to one embodiment includes a liquid crystal panel that displays a coded aperture pattern, an imaging element, and an optical system disposed between the liquid crystal panel and the imaging element, the liquid crystal panel having a liquid crystal layer including liquid crystal molecules and a polymer. a first substrate having a first electrode, a second substrate facing the first substrate and having a second electrode, and the liquid crystal layer disposed between the first substrate and the second substrate, the liquid crystal layer being in a transparent state when no electric field is applied to the liquid crystal layer, and in a scattering state when an electric field is applied to the liquid crystal layer, the first substrate having a first alignment film covering the first electrode and in contact with the liquid crystal layer, the second substrate having a second alignment film covering the second electrode and in contact with the liquid crystal layer, the first alignment film and the second alignment film being vertical alignment films. . [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is an exploded perspective view showing an example of a configuration of a camera module according to an embodiment. [Diagram 2] FIG. 2 is a plan view showing an example of a pattern of an incident light control region formed on a liquid crystal panel. [Diagram 3] FIG. 3 is a plan view showing another example of a pattern of the incident light control region formed on the liquid crystal panel. [Figure 4] FIG. 4 is a diagram for explaining the principle of calculating the distance to a subject using a camera module. [Diagram 5] FIG. 5 is a schematic cross-sectional view of a liquid crystal panel. [Figure 6] FIG. 6 is a cross-sectional view illustrating an example of a configuration of a liquid crystal layer. [Figure 7] FIG. 7 is a diagram showing a liquid crystal layer in an OFF state and an ON state. [Figure 8] FIG. 8 is a diagram showing a liquid crystal layer in an OFF state and an ON state according to the first modified example. [Figure 9] FIG. 9 is a diagram showing a liquid crystal layer in an OFF state and an ON state according to the second modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment will be described with reference to the drawings. The disclosure is merely an example, and those who are skilled in the art can easily conceive of appropriate modifications while keeping the gist of the invention are naturally included in the scope of the present invention. In addition, the drawings may be shown in a schematic manner compared to the embodiment in order to make the explanation clearer, but they are merely an example and do not limit the interpretation of the present invention. In addition, in this specification and each figure, components that perform the same or similar functions as those described above with respect to the previous figures are given the same reference numerals, and duplicate detailed explanations may be omitted.

[0010] In addition, in the drawings, an X-axis, a Y-axis, and a Z-axis that are perpendicular to each other are shown as necessary for ease of understanding. The direction along the X-axis is referred to as the X-direction or first direction X, the direction along the Y-axis is referred to as the Y-direction or second direction Y, and the direction along the Z-axis is referred to as the Z-direction or third direction Z.

[0011] In this specification, we describe a camera module that can use an image of a subject captured by a camera to calculate the distance from the camera to the subject in the image (hereinafter simply referred to as the distance to the subject).

[0012] As a technique for calculating the distance to a subject from an image, for example, coded aperture technology can be used. Although a detailed explanation is omitted, coded aperture technology is a technique for calculating the distance to a subject by analyzing the blur that occurs in an image according to the position of the subject.

[0013] That is, by using the coded aperture technique described above, it is possible to calculate the distance to an object based on an image and create a depth map that indicates the distance to the object. Note that the process of calculating the distance to the object and the process of creating the depth map are executed by a controller (CPU) that controls the operation of the camera module, or a controller of an electronic device connected to the camera module (an electronic device in which the camera module is mounted).

[0014] Fig. 1 is an exploded perspective view showing an example of the configuration of a camera module CM according to an embodiment. As shown in Fig. 1, the camera module CM includes a liquid crystal panel PNL, an imaging element (image sensor) IS arranged on the rear side of the liquid crystal panel PNL, and an optical system OS arranged between the liquid crystal panel PNL and the imaging element IS. That is, in the camera module CM, the liquid crystal panel PNL, the optical system OS, and the imaging element IS are arranged in this order along the third direction Z. The optical system OS includes at least one lens, and the optical system OS and the imaging element IS configure a camera that captures an image.

[0015] Although the details will be described later, the liquid crystal panel PNL includes a first substrate (array substrate), a second substrate (opposing substrate), and a liquid crystal layer disposed between the first substrate and the second substrate. The liquid crystal layer is a polymer-dispersed liquid crystal. The liquid crystal panel PNL according to this embodiment corresponds to a reverse mode in which, for example, when no electric field is applied to the liquid crystal layer, the liquid crystal layer is in a transparent state, and when an electric field is applied to the liquid crystal layer, the liquid crystal layer is in a scattering state. The transparent state is a state in which light incident on the liquid crystal layer is transmitted without being scattered in the liquid crystal layer. The scattering state is a state in which light incident on the liquid crystal layer is scattered in the liquid crystal layer. The reverse mode has an advantage of being more responsive than the normal mode in which the liquid crystal layer is in a scattering state when no electric field is applied to the liquid crystal layer, and in a transparent state when an electric field is applied to the liquid crystal layer. The liquid crystal panel PNL may be driven by a simple matrix method or an active matrix method. In this embodiment, a case in which the liquid crystal panel PNL is driven by an active matrix method will be described.

[0016] In the camera module CM according to this embodiment, when the liquid crystal panel PNL is in a transparent state, light transmitted through the liquid crystal panel PNL and the optical system OS is incident on the image sensor IS. This allows the camera module CM to capture an image based on the light incident on the image sensor IS.

[0017] On the other hand, when the liquid crystal panel PNL is in a scattering state, a coded aperture pattern is displayed on the liquid crystal panel PNL, and a large number of incident light control regions are formed. In other words, light that has passed through the liquid crystal panel PNL on which the coded aperture pattern is displayed and the optical system OS is incident on the image sensor IS. This allows the camera module CM to calculate the distance to the subject from an image based on the light incident on the image sensor IS using the coded aperture technology described above.

[0018] Note that Figure 1 is a diagram for explaining the positional relationship in the third direction Z of the liquid crystal panel PNL, the optical system OS, and the image sensor IS, and in Figure 1, the sizes and shapes, etc. of the liquid crystal panel PNL, the optical system OS, and the image sensor IS are shown in a simplified manner.

[0019] 2 and 3 are plan views showing examples of patterns of the incident light control area PCA formed on the liquid crystal panel PNL. The incident light control area PCA has a light-shielding area LSA that blocks the incident light incident on the image sensor IS, and a light-transmitting area TA that transmits the incident light incident on the image sensor IS. The incident light control area PCA has, for example, a circular shape, and the light-shielding area LSA includes at least a circular ring portion located on the outermost periphery of the incident light control area PCA. In FIG. 2 and FIG. 3, the area with dots corresponds to the light-shielding area LSA, and the other area corresponds to the light-transmitting area TA. Note that the area with dots in FIG. 2 may be referred to as a first light-shielding area LSA1, and the area other than the first light-shielding area LSA1 may be referred to as a first light-transmitting area TA1. Also, the area with dots in FIG. 3 may be referred to as a second light-shielding area LSA2, and the area other than the second light-shielding area LSA2 may be referred to as a second light-transmitting area TA2. As described above, the incident light control area PCA is formed when the liquid crystal panel PNL is in a scattering state. That is, the light-shielding area LSA included in the incident light control area PCA is formed by applying a voltage to the electrode arranged at a position overlapping the light-shielding area LSA and driving the liquid crystal layer. The pattern of the incident light control area PCA formed on the liquid crystal panel PNL is not limited to those shown in FIGS. 2 and 3, and any pattern can be applied.

[0020] Here, the principle of calculating the distance to the subject using the image captured by the above-mentioned camera module CM will be briefly described with reference to Fig. 4. Fig. 4 shows the positional relationship between the camera module CM and the subject S. As already described, the camera module CM includes a liquid crystal panel PNL, an image sensor IS, and an optical system OS disposed between the liquid crystal panel PNL and the image sensor IS.

[0021] Here, we will assume a case where the distance of the subject S shown in Fig. 4 is calculated. Generally, in a camera, the subject S can be photographed in a state where the subject S is in focus by changing the distance between the optical system OS and the image sensor IS, but as shown in Fig. 4, if the subject S is photographed in a state where the subject S is not in focus, a shift occurs between the focal position and the position of the imaging surface of the image sensor IS, and therefore the image based on the light incident on the image sensor IS is blurred.

[0022] According to the coded aperture technique described above, the distance to the subject S is calculated based on the blur that occurs in the image.

[0023] Note that while Figure 4 shows the case where light passes through the first light-transmitting region TA1, for example, by preparing two light-transmitting regions (first light-transmitting region TA1, second light-transmitting region TA2) as described above and calculating the distance to the subject using multiple images based on light that has passed through each of the two light-transmitting regions (i.e., multiple blur patterns based on light that has passed through different light-transmitting regions), the accuracy of calculating the distance (ranging accuracy) can be improved.

[0024] Next, a configuration example of the liquid crystal panel PNL will be described below. Fig. 5 is a schematic cross-sectional view of the liquid crystal panel PNL shown in Fig. 1. The liquid crystal panel PNL includes a first substrate SUB1, a second substrate SUB2, a liquid crystal layer LC, and a seal SE. The first substrate SUB1 and the second substrate SUB2 face each other. The liquid crystal layer LC is disposed between the first substrate SUB1 and the second substrate SUB2. The seal SE bonds the first substrate SUB1 and the second substrate SUB2 together and seals the liquid crystal layer LC. Note that the liquid crystal panel PNL is not provided with a color filter or a light source because it is only required to display a coded aperture pattern and is not required to display a visible image.

[0025] The first substrate SUB1 includes a transparent substrate 10, a pixel electrode 11 (first electrode), and an alignment film 12 (first alignment film). The second substrate SUB2 includes a transparent substrate 20, a common electrode 21 (second electrode), and an alignment film 22 (second alignment film). The pixel electrode 11 and the common electrode 21 face each other. The alignment film 12 covers the pixel electrode 11 and is in contact with the liquid crystal layer LC. The alignment film 22 covers the common electrode 21 and is in contact with the liquid crystal layer LC. The pixel electrode 11 and the common electrode 21 are formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The alignment films 12 and 22 are formed of, for example, a polyimide film.

[0026] Fig. 6 is a cross-sectional view for explaining one configuration example of the liquid crystal layer LC. As shown in Fig. 6, the liquid crystal layer LC has liquid crystal molecules 31 and a polymer 32. The alignment films 12 and 22 are vertical alignment films exhibiting a pretilt angle of 90 degrees (i.e., vertical alignment films having an alignment regulating force along the third direction Z), and the liquid crystal molecules 31 and the polymer 32 are aligned according to the pretilt angle.

[0027] Each of the liquid crystal molecules 31 and the polymer 32 has refractive index anisotropy or optical anisotropy. As described above, since it is assumed here that the liquid crystal panel PNL corresponds to the reverse mode, the liquid crystal molecules 31 are negative type liquid crystal molecules having negative dielectric anisotropy. The liquid crystal molecules 31 and the polymer 32 have different responsiveness to an electric field. More specifically, the responsiveness of the polymer 32 to an electric field is lower than the responsiveness of the liquid crystal molecules 31 to an electric field. For this reason, the alignment direction of the polymer 32 hardly changes regardless of the electric field between the pixel electrode 11 and the common electrode 21, as will be described in detail later. On the other hand, the alignment direction of the liquid crystal molecules 31 changes in response to the electric field.

[0028] Fig. 7 is a diagram showing the liquid crystal layer LC shown in Fig. 6 in an off state and an on state. Fig. 7(a) is a diagram showing the liquid crystal layer LC in an off state. The off state corresponds to a state where no voltage is applied to the liquid crystal layer LC (for example, a state where the potential difference between the pixel electrode 11 and the common electrode 21 is almost zero).

[0029] The long axes of the liquid crystal molecules 31 and the polymer 32 are parallel to each other. As described above, it is assumed here that the liquid crystal molecules 31 and the polymer 32 are aligned by the alignment films 12 and 22 having an alignment regulating force substantially parallel to the third direction Z, and therefore the long axes of the liquid crystal molecules 31 and the polymer 32 are both parallel to the third direction Z.

[0030] The liquid crystal molecules 31 and the polymer 32 have approximately the same refractive index anisotropy. In other words, the ordinary refractive indexes of the liquid crystal molecules 31 and the polymer 32 are approximately the same, and the extraordinary refractive indexes of the liquid crystal molecules 31 and the polymer 32 are approximately the same. Therefore, there is almost no difference in refractive index between the liquid crystal molecules 31 and the polymer 32 in all directions including the first direction X, the second direction Y, and the third direction Z. As a result, light incident on the liquid crystal layer LC is transmitted through the liquid crystal layer LC.

[0031] FIG. 7(b) is a diagram showing the liquid crystal layer LC in an on-state. The on-state corresponds to a state in which a voltage is applied to the liquid crystal layer LC (for example, a state in which the potential difference between the pixel electrode 11 and the common electrode 21 is equal to or greater than a threshold value). As described above, the responsiveness of the polymer 32 to an electric field is lower than that of the liquid crystal molecules 31 to an electric field, and the orientation direction of the polymer 32 hardly changes regardless of the presence or absence of an electric field. On the other hand, the orientation direction of the liquid crystal molecules 31 changes in response to an electric field when a high voltage equal to or greater than a threshold value is applied to the liquid crystal layer LC. That is, as shown in FIG. 7(b), the long axis of the polymer 32 is almost parallel to the third direction Z, whereas the long axis of the liquid crystal molecules 31 is inclined with respect to the third direction Z. As described above, since the liquid crystal molecules 31 are negative type liquid crystal molecules, the liquid crystal molecules 31 are oriented along a direction in which their long axes intersect with the electric field. That is, the long axis of the liquid crystal molecules 31 and the long axis of the polymer 32 intersect with each other. Therefore, a large refractive index difference occurs between the liquid crystal molecules 31 and the polymer 32 in all directions including the first direction X, the second direction Y, and the third direction Z. As a result, the light incident on the liquid crystal layer LC is isotropically scattered within the liquid crystal layer LC, and an incident light control area PCA is formed on the liquid crystal panel PNL (a coded aperture pattern is displayed).

[0032] As described above, the camera module CM according to this embodiment includes a liquid crystal panel PNL having a liquid crystal layer LC of polymer-dispersed liquid crystal, an optical system OS, and an image sensor IS, and when the liquid crystal layer LC is in the on state, a large number of incident light control areas PCA are formed in the liquid crystal panel PNL. Therefore, when the liquid crystal layer LC is in the on state, the camera module CM functions as a distance measuring sensor that calculates the distance to a subject from an image based on light incident on the image sensor IS, and when the liquid crystal layer LC is in the off state, it can function as a camera that captures an image based on light incident on the image sensor IS.

[0033] The polymer-dispersed liquid crystal layer LC does not require a polarizing plate, and therefore has a higher transmittance than other liquid crystal layers that do require a polarizing plate. Therefore, when the camera module CM is made to function as a camera, more light can be made to enter the image sensor IS than when other camera modules using liquid crystal panels with other liquid crystal layers are made to function as cameras, making it possible to capture high-quality images.

[0034] Moreover, the camera module CM according to this embodiment uses a liquid crystal panel PNL including alignment films 12 and 22 (vertical alignment films) having an alignment regulating force along the third direction Z, and a liquid crystal layer LC including negative type liquid crystal molecules 31 and polymer 32 aligned along the third direction Z by the vertical alignment films. In general, when a liquid crystal panel includes an alignment film (horizontal alignment film) having an alignment regulating force along the horizontal direction, and a liquid crystal layer including positive type liquid crystal molecules and polymer aligned along the horizontal direction by the horizontal alignment film, light incident on the liquid crystal layer in the on-state is not scattered isotropically within the liquid crystal layer, but is scattered depending on a predetermined direction. When such a liquid crystal panel is used in a camera module, there is a risk that the distance to a subject cannot be calculated (distance measured) with high accuracy when the camera module is made to function as a distance measuring sensor. However, as described above, the camera module CM of this embodiment uses a liquid crystal panel PNL including a vertical alignment film, so that light incident on the liquid crystal layer LC can be isotropically scattered within the liquid crystal layer LC, making it possible to accurately calculate (measure) the distance to the subject.

[0035] (First Modification) In the embodiment described above, the liquid crystal layer LC includes liquid crystal molecules 31 and polymer 32 oriented along the third direction Z, but the liquid crystal layer LC may include liquid crystal molecules 31 and polymer 32 that are twistedly oriented.

[0036] 8 is a diagram showing a liquid crystal layer LC including twist-oriented liquid crystal molecules 31 and a polymer 32, and is a schematic diagram showing a liquid crystal layer LC in an off state and an on state. The alignment treatment direction AD1 of the alignment film 12 and the alignment treatment direction AD2 of the alignment film 22 are different from each other. In FIG. 8, it is assumed that the alignment treatment direction AD1 of the alignment film 12 and the alignment treatment direction AD2 of the alignment film 22 are perpendicular to each other. The alignment treatment may be a rubbing treatment or a photo-alignment treatment.

[0037] In the liquid crystal layer LC, a chiral agent is added to the liquid crystal molecules 31 and the polymer 32, and the liquid crystal molecules 31 and the polymer 32 are twisted. In Fig. 8, it is assumed that the liquid crystal molecules 31 and the polymer 32 are twisted at 90° between the alignment films 12 and 22. The liquid crystal molecules 31 are positive type liquid crystal molecules having positive dielectric anisotropy.

[0038] FIG. 8(a) is a diagram showing a liquid crystal layer LC in an off state. As shown in FIG. 8(a), the liquid crystal molecules 31 and the polymer 32 are aligned in the long axis direction in the liquid crystal layer LC. The liquid crystal molecules 31 and the polymer 32 have substantially the same refractive index anisotropy. That is, the ordinary refractive indexes of the liquid crystal molecules 31 and the polymer 32 are substantially the same, and the extraordinary refractive indexes of the liquid crystal molecules 31 and the polymer 32 are substantially the same. Therefore, there is almost no difference in refractive index between the liquid crystal molecules 31 and the polymer 32 in all directions including the first direction X, the second direction Y, and the third direction Z. As a result, light incident on the liquid crystal layer LC is transmitted through the liquid crystal layer LC.

[0039] FIG. 8(b) is a schematic diagram showing the liquid crystal layer LC in the on state. As described above, the responsiveness of the polymer 32 to the electric field is lower than that of the liquid crystal molecules 31 to the electric field, and the orientation direction of the polymer 32 hardly changes regardless of the presence or absence of the electric field. On the other hand, the orientation direction of the liquid crystal molecules 31 changes according to the electric field when a high voltage equal to or higher than the threshold value is applied to the liquid crystal layer LC. That is, as shown in FIG. 8(b), the long axis of the polymer 32 hardly changes from the case of the off state shown in FIG. 8(a), while the long axis of the liquid crystal molecules 31 is parallel to the third direction Z. As described above, it is assumed here that the liquid crystal molecules 31 are positive type liquid crystal molecules, so that the long axis is oriented along the electric field, and the long axis of the liquid crystal molecules 31 is parallel to the third direction Z. Therefore, the long axis of the liquid crystal molecules 31 and the long axis of the polymer 32 cross each other. Therefore, a large refractive index difference occurs between the liquid crystal molecules 31 and the polymer 32 in all directions including the first direction X, the second direction Y, and the third direction Z. According to this, the light incident on the liquid crystal layer LC is isotropically scattered within the liquid crystal layer LC, and an incident light control area PCA is formed on the liquid crystal panel PNL (a coded aperture pattern is displayed).

[0040] As described above, even when the liquid crystal layer LC includes twist-oriented liquid crystal molecules 31 and polymer 32, no polarizing plate is required as in the case shown in Fig. 7, so that high-quality images can be captured when the camera module CM is made to function as a camera. Furthermore, when the liquid crystal layer LC includes twist-oriented liquid crystal molecules 31 and polymer 32, it is possible to impart isotropy to scattered light even if the alignment films 12 and 22 are horizontal alignment films, so that the distance to a subject can be calculated with high accuracy when the camera module CM is made to function as a distance measuring sensor.

[0041] (Second Modification) In the embodiment described above, the liquid crystal layer LC includes liquid crystal molecules 31 and polymer 32 oriented along the third direction Z, but the liquid crystal layer LC may further include dichroic dye molecules 33.

[0042] 9 is a diagram showing a liquid crystal layer LC in which a dichroic dye (guest) is added to the liquid crystal layer LC shown in FIG. 7, and is a diagram showing a liquid crystal layer LC in an off state and an on state. As shown in FIG. 9(a), the dichroic dye molecules 33 are aligned in the same direction as the liquid crystal molecules 31. That is, the long axes of the liquid crystal molecules 31 and the dichroic dye molecules 33 are parallel to each other. In FIG. 9, as in the case shown in FIG. 7, it is assumed that the liquid crystal molecules 31 and the polymer 32 are aligned by the alignment films 12 and 22 having an alignment regulating force substantially parallel to the third direction Z, so that the long axes of the liquid crystal molecules 31, the long axes of the polymer 32, and the long axes of the dichroic dye molecules 33 are all parallel to the third direction Z.

[0043] The liquid crystal molecules 31 and the polymer 32 have approximately the same refractive index anisotropy. That is, the ordinary refractive indexes of the liquid crystal molecules 31 and the polymer 32 are approximately the same, and the extraordinary refractive indexes of the liquid crystal molecules 31 and the polymer 32 are approximately the same. Therefore, there is almost no difference in refractive index between the liquid crystal molecules 31 and the polymer 32 in all directions including the first direction X, the second direction Y, and the third direction Z.

[0044] Moreover, the dichroic dye molecules 33 have different absorbances in the long axis direction and the short axis direction. More specifically, the dichroic dye molecules 33 absorb light vibrating in the long axis direction and transmit light vibrating in the short axis direction. As described above, the dichroic dye molecules 33 are oriented following the liquid crystal molecules 31, and in the off state, their long axes are parallel to the third direction Z, and light vibrating in the short axis direction is transmitted.

[0045] As described above, in the off state, there is almost no difference in refractive index between the liquid crystal molecules 31 and the polymer 32 in any direction, and the dichroic dye molecules 33 are in a state where they transmit light vibrating in the short axis direction, so that light incident on the liquid crystal layer LC is transmitted through the liquid crystal layer LC.

[0046] FIG. 9(b) is a diagram showing the liquid crystal layer LC in the on state. As described above, the responsiveness of the polymer 32 to the electric field is lower than that of the liquid crystal molecules 31 to the electric field, and the orientation direction of the polymer 32 hardly changes regardless of the presence or absence of the electric field. On the other hand, the orientation direction of the liquid crystal molecules 31 changes according to the electric field when a high voltage equal to or higher than the threshold value is applied to the liquid crystal layer LC. That is, as shown in FIG. 9(b), the long axis of the polymer 32 is almost parallel to the third direction Z, while the long axis of the liquid crystal molecules 31 is inclined with respect to the third direction Z. As in the case of FIG. 7, the liquid crystal molecules 31 are negative type liquid crystal molecules, so that the liquid crystal molecules 31 are oriented along the direction in which their long axes intersect with the electric field. That is, the long axis of the liquid crystal molecules 31 and the long axis of the polymer 32 intersect with each other. Therefore, a large refractive index difference occurs between the liquid crystal molecules 31 and the polymer 32 in all directions including the first direction X, the second direction Y, and the third direction Z.

[0047] As described above, the dichroic dye molecules 33 are oriented in accordance with the liquid crystal molecules 31, and in the on state, their major axes are oriented in a direction intersecting the electric field, and they absorb light vibrating in the major axis direction.

[0048] As described above, in the on state, a large refractive index difference occurs between the liquid crystal molecules 31 and the polymer 32 in all directions, and the dichroic dye molecules 33 are in a state in which they absorb light vibrating in the long axis direction, so that the light incident on the liquid crystal layer LC is scattered isotropically within the liquid crystal layer LC, and an incident light control area PCA is formed in the liquid crystal panel PNL (a coded aperture pattern is formed).

[0049] As described above, even when the liquid crystal layer LC further contains the dichroic dye molecules 33, a high-quality image can be captured when the camera module CM is made to function as a camera, since no polarizing plate is required as in the case shown in Fig. 7. In this case, since the liquid crystal panel PNL including the vertical alignment film is used as in the case shown in Fig. 7, the light incident on the liquid crystal layer LC can be isotropically scattered within the liquid crystal layer LC, and the distance to the subject can be calculated with high accuracy.

[0050] Furthermore, when the liquid crystal layer LC contains dichroic dye molecules 33, in the on state, the dichroic dye molecules 33 absorb light vibrating in the long axis direction, making it possible to color the display surface of the liquid crystal panel PNL, thereby improving the contrast of the liquid crystal panel PNL.

[0051] According to the embodiment described above, it is possible to provide a camera module CM equipped with a liquid crystal panel PNL having high transmittance.

[0052] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0053] CM...camera module, PNL...liquid crystal panel, IS...imaging element, OS...optical system, LC...liquid crystal layer, 12, 22...alignment film, 31...liquid crystal molecule, 32...polymer, 33...dichroic dye molecule.

Claims

1. a liquid crystal panel for displaying a coded aperture pattern; An imaging element; an optical system disposed between the liquid crystal panel and the image sensor; The liquid crystal panel is A liquid crystal layer including liquid crystal molecules and a polymer; a first substrate having a first electrode, a second substrate facing the first substrate and having a second electrode, and the liquid crystal layer disposed between the first substrate and the second substrate; When no electric field is applied to the liquid crystal layer, the liquid crystal layer is in a transparent state, and when an electric field is applied to the liquid crystal layer, the liquid crystal layer is in a scattering state. the first substrate has a first alignment film that covers the first electrode and is in contact with the liquid crystal layer; the second substrate has a second alignment film covering the second electrode and in contact with the liquid crystal layer; The first alignment film and the second alignment film are vertical alignment films. Camera module.

2. The liquid crystal layer further includes dichroic dye molecules that are aligned following the liquid crystal molecules. The camera module of claim 1 .

3. the first substrate has a first alignment film that covers the first electrode and is in contact with the liquid crystal layer; the second substrate has a second alignment film covering the second electrode and in contact with the liquid crystal layer; The first alignment film and the second alignment film are horizontal alignment films having different alignment treatment directions, The liquid crystal layer includes the liquid crystal molecules in a twisted orientation and the polymer. The camera module of claim 1 .

Images